File 0007-use-more-properties-according-to-XLFD.patch of Package fonttosfnt.20912
From 5aabd5e0caba5ff6d71a1e05f2917ed20f5c0899 Mon Sep 17 00:00:00 2001
From: Christopher Zimmermann <madroach@gmerlin.de>
Date: Tue, 7 Jul 2020 21:02:56 +0200
Subject: [PATCH 07/14] use more properties according to XLFD
---
fonttosfnt.h | 23 +-
read.c | 37 +-
struct.c | 125 ++-
util.c | 13 +
write.c | 49 +-
xlfd.txt | 2970 ++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 3146 insertions(+), 71 deletions(-)
create mode 100644 xlfd.txt
diff --git a/fonttosfnt.h b/fonttosfnt.h
index 202ab5a..a05e036 100644
--- a/fonttosfnt.h
+++ b/fonttosfnt.h
@@ -86,6 +86,22 @@ typedef struct _FontNameEntry {
char *value;
} FontNameEntryRec, *FontNameEntryPtr;
+typedef struct _Metrics {
+ int height;
+ int maxX;
+ int minX;
+ int maxY;
+ int minY;
+ int xHeight;
+ int capHeight;
+ int maxAwidth;
+ int awidth;
+ int ascent;
+ int descent;
+ int underlinePosition;
+ int underlineThickness;
+} MetricsRec, *MetricsPtr;
+
typedef struct _Font {
int numNames;
struct _FontNameEntry *names;
@@ -93,8 +109,8 @@ typedef struct _Font {
int weight; /* as in the OS/2 table */
int width; /* as in the OS/2 table */
int italicAngle; /* degrees c-clockwise from the vertical */
- int underlinePosition;
- int underlineThickness;
+ MetricsRec pxMetrics;
+ MetricsRec metrics;
unsigned foundry;
struct _Strike *strikes;
} FontRec, *FontPtr;
@@ -153,7 +169,7 @@ int findCode(CmapPtr, int);
BitmapPtr strikeBitmapIndex(StrikePtr, CmapPtr, int);
void strikeMetrics(StrikePtr, int*, int*, int*, int*, int*);
int glyphMetrics(FontPtr, int, int*, int*, int*, int*, int*);
-void fontMetrics(FontPtr, int*, int*, int*, int*, int*);
+void fontMetrics(FontPtr, MetricsPtr);
int maxIndex(CmapPtr);
int readFile(char *filename, FontPtr);
@@ -173,6 +189,7 @@ int macTime(int *, unsigned *);
unsigned faceFoundry(FT_Face);
char *faceEncoding(FT_Face);
int faceFlags(FT_Face);
+int faceIntProp(FT_Face, const char *);
int faceWeight(FT_Face);
int faceWidth(FT_Face);
int faceItalicAngle(FT_Face);
diff --git a/read.c b/read.c
index a22ce41..db79a59 100644
--- a/read.c
+++ b/read.c
@@ -258,30 +258,6 @@ readFile(char *filename, FontPtr font)
i++;
#endif
font->numNames = i;
-
- font->flags = faceFlags(face) | (symbol ? FACE_SYMBOL : 0);
- font->weight = faceWeight(face);
- font->width = faceWidth(face);
- font->foundry = faceFoundry(face);
- font->italicAngle = faceItalicAngle(face);
-
- rc = FT_Get_BDF_Property(face, "UNDERLINE_POSITION", &prop);
- if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER)
- font->underlinePosition =
- (double)prop.u.integer / face->available_sizes[0].height *
- TWO_SIXTEENTH;
- else
- font->underlinePosition =
- - 1.5 / face->available_sizes[0].height * TWO_SIXTEENTH;
-
- rc = FT_Get_BDF_Property(face, "UNDERLINE_THICKNESS", &prop);
- if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER)
- font->underlineThickness =
- (double)prop.u.integer / face->available_sizes[0].height *
- TWO_SIXTEENTH;
- else
- font->underlineThickness =
- 1.0 / face->available_sizes[0].height * TWO_SIXTEENTH;
}
if(face->num_fixed_sizes == 0) {
@@ -304,6 +280,19 @@ readFile(char *filename, FontPtr font)
return -1;
}
+ font->flags = faceFlags(face) | (symbol ? FACE_SYMBOL : 0);
+ font->weight = faceWeight(face);
+ font->width = faceWidth(face);
+ font->foundry = faceFoundry(face);
+ font->italicAngle = faceItalicAngle(face);
+ font->pxMetrics.height = face->available_sizes[0].height;
+ font->pxMetrics.xHeight = faceIntProp(face, "X_HEIGHT");
+ font->pxMetrics.capHeight = faceIntProp(face, "CAP_HEIGHT");
+ font->pxMetrics.ascent = faceIntProp(face, "FONT_ASCENT");
+ font->pxMetrics.descent = faceIntProp(face, "FONT_DESCENT");
+ font->pxMetrics.underlinePosition = faceIntProp(face, "UNDERLINE_POSITION");
+ font->pxMetrics.underlineThickness = faceIntProp(face, "UNDERLINE_THICKNESS");
+
for(int i = 0; i < face->num_fixed_sizes; i++) {
if(verbose_flag)
fprintf(stderr, "size %d: %dx%d\n",
diff --git a/struct.c b/struct.c
index bcb07ba..1c14931 100644
--- a/struct.c
+++ b/struct.c
@@ -42,8 +42,32 @@ makeFont(void)
font->weight = 500;
font->width = 5;
font->italicAngle = 0;
- font->underlinePosition = - TWO_SIXTEENTH;
- font->underlineThickness = TWO_SIXTEENTH;
+ font->pxMetrics.height = UNDEF;
+ font->pxMetrics.maxX = UNDEF;
+ font->pxMetrics.minX = UNDEF;
+ font->pxMetrics.maxY = UNDEF;
+ font->pxMetrics.minY = UNDEF;
+ font->pxMetrics.xHeight = UNDEF;
+ font->pxMetrics.capHeight = UNDEF;
+ font->pxMetrics.maxAwidth = UNDEF;
+ font->pxMetrics.awidth = UNDEF;
+ font->pxMetrics.ascent = UNDEF;
+ font->pxMetrics.descent = UNDEF;
+ font->pxMetrics.underlinePosition = UNDEF;
+ font->pxMetrics.underlineThickness = UNDEF;
+ font->metrics.height = UNDEF;
+ font->metrics.maxX = UNDEF;
+ font->metrics.minX = UNDEF;
+ font->metrics.maxY = UNDEF;
+ font->metrics.minY = UNDEF;
+ font->metrics.xHeight = UNDEF;
+ font->metrics.capHeight = UNDEF;
+ font->metrics.maxAwidth = UNDEF;
+ font->metrics.awidth = UNDEF;
+ font->metrics.ascent = UNDEF;
+ font->metrics.descent = UNDEF;
+ font->metrics.underlinePosition = UNDEF;
+ font->metrics.underlineThickness = UNDEF;
font->foundry = makeName("UNKN");
font->strikes = NULL;
return font;
@@ -480,31 +504,90 @@ glyphMetrics(FontPtr font, int code,
}
void
-fontMetrics(FontPtr font,
- int *max_awidth_return,
- int *min_x_return, int *min_y_return,
- int *max_x_return, int *max_y_return)
+fontMetrics(FontPtr font, MetricsPtr metrics)
{
int i, rc;
- int max_awidth = 0;
- int min_x = 10000 * 65536, min_y = 10000 * 65536;
- int max_x = -10000 * 65536, max_y = -10000 * 65536;
+ double sumAwidth = 0;
+ unsigned count = 0;
+
+ metrics->height = UNDEF /* TODO */;
+ metrics->maxAwidth = 0;
+ metrics->maxX = -10000 * TWO_SIXTEENTH;
+ metrics->maxY = -10000 * TWO_SIXTEENTH;
+ metrics->minX = 10000 * TWO_SIXTEENTH;
+ metrics->minY = 10000 * TWO_SIXTEENTH;
+ metrics->ascent = UNDEF;
+ metrics->descent = UNDEF;
+ metrics->underlinePosition = UNDEF;
+ metrics->underlineThickness = UNDEF;
+
for(i = 0; i < FONT_CODES; i++) {
int awidth, x0, y0, x1, y1;
rc = glyphMetrics(font, i, &awidth, &x0, &y0, &x1, &y1);
if(rc < 0)
continue;
- if(awidth > max_awidth)
- max_awidth = awidth;
- if(x0 < min_x) min_x = x0;
- if(y0 < min_y) min_y = y0;
- if(x1 > max_x) max_x = x1;
- if(y1 > max_y) max_y = y1;
+
+ if(awidth > metrics->maxAwidth) metrics->maxAwidth = awidth;
+ if(x0 < metrics->minX) metrics->minX = x0;
+ if(y0 < metrics->minY) metrics->minY = y0;
+ if(x1 > metrics->maxX) metrics->maxX = x1;
+ if(y1 > metrics->maxY) metrics->maxY = y1;
+
+ if(awidth > 0) {
+ sumAwidth += awidth;
+ count++;
+ }
}
- if(max_awidth_return) *max_awidth_return = max_awidth;
- if(min_x_return) *min_x_return = min_x;
- if(min_y_return) *min_y_return = min_y;
- if(max_x_return) *max_x_return = max_x;
- if(max_y_return) *max_y_return = max_y;
-}
+ if (count) metrics->awidth = sumAwidth / count;
+
+ if(font->pxMetrics.ascent == UNDEF)
+ metrics->ascent = metrics->maxY;
+ else
+ metrics->ascent =
+ font->pxMetrics.ascent
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+
+ if(font->pxMetrics.descent == UNDEF)
+ metrics->descent = metrics->minY;
+ else
+ metrics->descent =
+ font->pxMetrics.descent
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+
+ if(font->pxMetrics.capHeight == UNDEF)
+ /* TODO get ascent of letter 'X' - how to do lookups of ascii codes ? */
+ metrics->capHeight = metrics->ascent;
+ else
+ metrics->capHeight =
+ font->pxMetrics.capHeight
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+
+ if(font->pxMetrics.xHeight == UNDEF)
+ /* TODO get ascent of letter 'x' - how to do lookups of ascii codes ? */
+ metrics->xHeight = metrics->ascent * 2 / 3;
+ else
+ metrics->xHeight =
+ font->pxMetrics.xHeight
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+
+ if(font->pxMetrics.underlinePosition == UNDEF)
+ metrics->underlinePosition = - metrics->descent * 2;
+ else
+ metrics->underlinePosition =
+ font->pxMetrics.underlinePosition
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+
+ if(font->pxMetrics.underlineThickness == UNDEF)
+ /* TODO: this could be refined according to
+ * X Logical Font Description Conventions (xlfd.txt)
+ * by also considering the font weight. */
+ /* make sure thickness is at least one pixel. */
+ metrics->underlineThickness =
+ TWO_SIXTEENTH
+ / (font->pxMetrics.height < 9 ? font->pxMetrics.height : 9);
+ else
+ metrics->underlineThickness =
+ font->pxMetrics.underlineThickness
+ * TWO_SIXTEENTH / font->pxMetrics.height;
+}
diff --git a/util.c b/util.c
index 594302a..1d61cca 100644
--- a/util.c
+++ b/util.c
@@ -395,6 +395,19 @@ faceFlags(FT_Face face)
return flags;
}
+int
+faceIntProp(FT_Face face, const char *name)
+{
+ int rc;
+ BDF_PropertyRec prop;
+
+ rc = FT_Get_BDF_Property(face, name, &prop);
+ if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER)
+ return prop.u.integer;
+ else
+ return UNDEF;
+}
+
char *
faceEncoding(FT_Face face)
{
diff --git a/write.c b/write.c
index 64b38b6..8f54625 100644
--- a/write.c
+++ b/write.c
@@ -61,7 +61,6 @@ static int writemaxp(FILE*, FontPtr);
static int writename(FILE*, FontPtr);
static int writepost(FILE*, FontPtr);
-int max_awidth, min_x, min_y, max_x, max_y;
static CmapPtr current_cmap = NULL;
static int numglyphs, nummetrics;
static int write_error_occurred, read_error_occurred;
@@ -219,7 +218,7 @@ writeFile(char *filename, FontPtr font)
int offset[15], length[15];
StrikePtr strike;
- fontMetrics(font, &max_awidth, &min_x, &min_y, &max_x, &max_y);
+ fontMetrics(font, &font->metrics);
out = fopen(filename, "wb+");
if(out == NULL)
@@ -451,10 +450,12 @@ writehead(FILE* out, FontPtr font)
writeLONG(out, time_hi); /* modified */
writeULONG(out, time_lo);
- writeUSHORT(out, FONT_UNITS_FLOOR(min_x));
- writeUSHORT(out, FONT_UNITS_FLOOR(min_y));
- writeUSHORT(out, FONT_UNITS_CEIL(max_x));
- writeUSHORT(out, FONT_UNITS_CEIL(max_y));
+ /* bounding box for all glyphs */
+ writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX));
+ writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.minY));
+ writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxX));
+ writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxY));
+
writeUSHORT(out, font->flags); /* macStyle */
writeUSHORT(out, 1); /* lowestRecPPEM */
writeSHORT(out, 0); /* fontDirectionHint */
@@ -849,13 +850,15 @@ writehhea(FILE* out, FontPtr font)
degreesToFraction(font->italicAngle, &num, &den);
writeULONG(out, 0x00010000); /* version */
- writeSHORT(out, FONT_UNITS_CEIL(max_y)); /* ascender */
- writeSHORT(out, FONT_UNITS_FLOOR(min_y)); /* descender */
+ writeSHORT(out, FONT_UNITS_CEIL(font->metrics.ascent)); /* ascender */
+ writeSHORT(out, 0-FONT_UNITS_CEIL(font->metrics.descent)); /* descender */
writeSHORT(out, 0); /* lineGap */
- writeUSHORT(out, FONT_UNITS(max_awidth)); /* advanceWidthMax */
- writeSHORT(out, FONT_UNITS_FLOOR(min_x)); /* minLeftSideBearing */
- writeSHORT(out, FONT_UNITS_FLOOR(min_x)); /* minRightSideBearing */
- writeSHORT(out, FONT_UNITS_CEIL(max_x)); /* xMaxExtent */
+ writeUSHORT(out, FONT_UNITS(font->metrics.maxAwidth)); /* advanceWidthMax */
+ /* TODO: the next three are not calculated according to spec, are they ?
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/hhea */
+ writeSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX)); /* minLeftSideBearing */
+ writeSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX)); /* minRightSideBearing */
+ writeSHORT(out, FONT_UNITS_CEIL(font->metrics.maxX)); /* xMaxExtent */
writeSHORT(out, den); /* caretSlopeRise */
writeSHORT(out, num); /* caretSlopeRun */
writeSHORT(out, 0); /* reserved */
@@ -974,8 +977,8 @@ writepost(FILE* out, FontPtr font)
writeULONG(out, 0x00030000); /* FormatType */
writeULONG(out, font->italicAngle); /* italicAngle */
- writeSHORT(out, FONT_UNITS(font->underlinePosition));
- writeSHORT(out, FONT_UNITS(font->underlineThickness));
+ writeSHORT(out, FONT_UNITS(font->metrics.underlinePosition));
+ writeSHORT(out, FONT_UNITS(font->metrics.underlineThickness));
writeULONG(out, fixed_pitch); /* isFixedPitch */
writeULONG(out, 0); /* minMemType42 */
writeULONG(out, 0); /* maxMemType42 */
@@ -990,7 +993,7 @@ writeOS2(FILE* out, FontPtr font)
int i;
writeUSHORT(out, 0x0001);
- writeSHORT(out, FONT_UNITS(max_awidth / 2)); /* xAvgCharWidth; */
+ writeSHORT(out, FONT_UNITS(font->metrics.awidth)); /* xAvgCharWidth; */
writeUSHORT(out, font->weight); /* usWeightClass; */
writeUSHORT(out, font->width); /* usWidthClass; */
writeSHORT(out, 0); /* fsType; */
@@ -1002,7 +1005,7 @@ writeOS2(FILE* out, FontPtr font)
writeSHORT(out, UNITS_PER_EM / 5); /* ySuperscriptYSize; */
writeSHORT(out, 0); /* ySuperscriptXOffset; */
writeSHORT(out, UNITS_PER_EM / 5); /* ySuperscriptYOffset; */
- writeSHORT(out, FONT_UNITS(font->underlineThickness));
+ writeSHORT(out, FONT_UNITS(font->metrics.underlineThickness));
/* yStrikeoutSize; */
writeSHORT(out, UNITS_PER_EM / 4); /* yStrikeoutPosition; */
writeSHORT(out, 0); /* sFamilyClass; */
@@ -1020,11 +1023,11 @@ writeOS2(FILE* out, FontPtr font)
writeUSHORT(out, i); /* fsSelection; */
writeUSHORT(out, 0x20); /* usFirstCharIndex; */
writeUSHORT(out, 0xFFFD); /* usLastCharIndex; */
- writeUSHORT(out, FONT_UNITS_CEIL(max_y)); /* sTypoAscender; */
- writeUSHORT(out, FONT_UNITS_FLOOR(min_y)); /* sTypoDescender; */
+ writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.ascent)); /* sTypoAscender; */
+ writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.descent)); /* sTypoDescender; */
writeUSHORT(out, 0); /* sTypoLineGap; */
- writeUSHORT(out, FONT_UNITS_CEIL(max_y)); /* usWinAscent; */
- writeUSHORT(out, -FONT_UNITS_FLOOR(min_y)); /* usWinDescent; */
+ writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxY)); /* usWinAscent; */
+ writeUSHORT(out, -FONT_UNITS_FLOOR(font->metrics.minY)); /* usWinDescent; */
writeULONG(out, 3); /* ulCodePageRange1; */
writeULONG(out, 0); /* ulCodePageRange2; */
return 0;
@@ -1064,11 +1067,11 @@ writePCLT(FILE* out, FontPtr font)
writeULONG(out, 0x00010000); /* version */
writeULONG(out, 0); /* FontNumber */
- writeUSHORT(out, FONT_UNITS(max_awidth)); /* pitch */
- writeUSHORT(out, FONT_UNITS(max_y)); /* xHeight */
+ writeUSHORT(out, FONT_UNITS(font->metrics.maxAwidth)); /* pitch */
+ writeUSHORT(out, FONT_UNITS(font->metrics.xHeight)); /* xHeight */
writeUSHORT(out, style); /* style */
writeUSHORT(out, 6 << 12); /* TypeFamily */
- writeUSHORT(out, FONT_UNITS(max_y)); /* CapHeight */
+ writeUSHORT(out, FONT_UNITS(font->metrics.xHeight)); /* CapHeight */
writeUSHORT(out, 0); /* SymbolSet */
writeCHARs(out, name, 16); /* TypeFace */
writeBYTEs(out, charComplement, 8); /* CharacterComplement */
diff --git a/xlfd.txt b/xlfd.txt
new file mode 100644
index 0000000..03840e0
--- /dev/null
+++ b/xlfd.txt
@@ -0,0 +1,2970 @@
+
+
+
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+ X Logical Font Description Conventions
+
+ Version 1.5
+
+ X Consortium Standard
+
+ X Version 11, Release 6.4
+
+
+
+
+
+
+ Jim Flowers
+ Digital Equipment Corporation
+
+
+
+
+
+
+ Version 1.5 edited by Stephen Gildea
+ X Consortium, Inc.
+
+
+
+
+
+
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+
+X Window System is a trademark of X Consortium, Inc.
+
+Helvetica and Times are registered trademarks of Linotype Company.
+
+ITC Avant Garde Gothic is a registered trademark of International Type-
+face Corporation.
+
+Times Roman is a registered trademark of Monotype Corporation.
+
+Bitstream Amerigo is a registered trademark of Bitstream Inc.
+
+Stone is a registered trademark of Adobe Systems Inc.
+
+Copyright (C) 1988, 1994 X Consortium
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Soft-
+ware"), to deal in the Software without restriction, including without
+limitation the rights to use, copy, modify, merge, publish, distribute,
+sublicense, and/or sell copies of the Software, and to permit persons to
+whom the Software is furnished to do so, subject to the following condi-
+tions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
+ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABIL-
+ITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+
+Except as contained in this notice, the name of the X Consortium shall
+not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization from
+the X Consortium.
+
+Copyright (C) 1988, 1989 Digital Equipment Corporation, Maynard MA. All
+rights reserved.
+
+Permission to use, copy, modify, and distribute this documentation for
+any purpose and without fee is hereby granted, provided that the above
+
+
+
+
+
+
+
+
+
+
+
+
+copyright notice and this permission notice appear in all copies. Digi-
+tal Equipment Corporation makes no representations about the suitability
+for any purpose of the information in this document. This documentation
+is provided as is without express or implied warranty.
+
+
+
+
+
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+
+1. Introduction
+
+It is a requirement that X client applications must be portable across
+server implementations, with very different file systems, naming conven-
+tions, and font libraries. However, font access requests, as defined by
+the X Window System Protocol, neither specify server-independent conven-
+tions for font names nor provide adequate font properties for logically
+describing typographic fonts.
+
+X clients must be able to dynamically determine the fonts available on
+any given server so that understandable information can be presented to
+the user or so that intelligent font fallbacks can be chosen. It is
+desirable for the most common queries to be accomplished without the
+overhead of opening each font and inspecting font properties, by means
+of simple ListFonts requests. For example, if a user selected a Hel-
+vetica typeface family, a client application should be able to query the
+server for all Helvetica fonts and present only those setwidths,
+weights, slants, point sizes, and character sets available for that fam-
+ily.
+
+This document gives a standard logical font description (hereafter
+referred to as XLFD) and the conventions to be used in the core protocol
+so that clients can query and access screen type libraries in a consis-
+tent manner across all X servers. In addition to completely specifying
+a given font by means of its FontName, the XLFD also provides for a
+standard set of key FontProperties that describe the font in more
+detail.
+
+The XLFD provides an adequate set of typographic font properties, such
+as CAP_HEIGHT, X_HEIGHT, and RELATIVE_SETWIDTH, for publishing and other
+applications to do intelligent font matching or substitution when han-
+dling documents created on some foreign server that use potentially
+unknown fonts. In addition, this information is required by certain
+clients to position subscripts automatically and determine small capital
+heights, recommended leading, word-space values, and so on.
+
+2. Requirements and Goals
+
+The XLFD meets the short-term and long-term goals to have a standard
+logical font description that:
+
+o Provides unique, descriptive font names that support simple pattern
+ matching
+
+o Supports multiple font vendors, arbitrary character sets, and
+ encodings
+
+o Supports naming and instancing of scalable and polymorphic fonts
+
+o Supports transformations and subsetting of fonts
+
+o Is independent of X server and operating or file system implementa-
+ tions
+
+
+
+
+ 1
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+o Supports arbitrarily complex font matching or substitution
+
+o Is extensible
+
+2.1. Provide Unique and Descriptive Font Names
+
+It should be possible to have font names that are long enough and
+descriptive enough to have a reasonable probability of being unique
+without inventing a new registration organization. Resolution and size-
+dependent font masters, multivendor font libraries, and so on must be
+anticipated and handled by the font name alone.
+
+The name itself should be structured to be amenable to simple pattern
+matching and parsing, thus allowing X clients to restrict font queries
+to some subset of all possible fonts in the server.
+
+2.2. Support Multiple Font Vendors and Character Sets
+
+The font name and properties should distinguish between fonts that were
+supplied by different font vendors but that possibly share the same
+name. We anticipate a highly competitive font market where users will
+be able to buy fonts from many sources according to their particular
+requirements.
+
+A number of font vendors deliver each font with all glyphs designed for
+that font, where charset mappings are defined by encoding vectors. Some
+server implementations may force these mappings to proprietary or stan-
+dard charsets statically in the font data. Others may desire to perform
+the mapping dynamically in the server. Provisions must be made in the
+font name that allows a font request to specify or identify specific
+charset mappings in server environments where multiple charsets are sup-
+ported.
+
+2.3. Support Scalable and Polymorphic Fonts
+
+If a font source can be scaled to an arbitrary size or varied in other
+ways, it should be possible for an application to determine that fact
+from the font name, and the application should be able to construct a
+font name for any specific instance.
+
+2.4. Support Transformations and Subsetting of Fonts
+
+Arbitrary two-dimensional linear transformations of fonts should be able
+to be requested by applications. Since such transformed fonts may be
+used for special effects requiring a few characters from each of many
+differently transformed fonts, it should be possible to request only a
+few characters from a font for efficiency.
+
+2.5. Be Independent of X Server and Operating or File System Implemen-
+tations
+
+X client applications that require a particular font should be able to
+use the descriptive name without knowledge of the file system or other
+repository in use by the server. However, it should be possible for
+
+
+
+ 2
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+servers to translate a given font name into a file name syntax that it
+knows how to deal with, without compromising the uniqueness of the font
+name. This algorithm should be reversible (exactly how this translation
+is done is implementation dependent).
+
+2.6. Support Arbitrarily Complex Font Matching and Substitution
+
+In addition to the font name, the XLFD should define a standard list of
+descriptive font properties, with agreed-upon fallbacks for all fonts.
+This allows client applications to derive font-specific formatting or
+display data and to perform font matching or substitution when asked to
+handle potentially unknown fonts, as required.
+
+2.7. Be Extensible
+
+The XLFD must be extensible so that new and/or private descriptive font
+properties can be added to conforming fonts without making existing X
+client or server implementations obsolete.
+
+3. X Logical Font Description
+
+XLFD is divided into two basic components: the FontName, which gives all
+font information needed to uniquely identify a font in X protocol
+requests (for example, OpenFont, ListFonts, and so on) and a variable
+list of optional FontProperties, which describe a font in more detail.
+
+The FontName is used in font queries and is returned as data in certain
+X protocol requests. It is also specified as the data value for the
+FONT item in the X Consortium Character Bitmap Distribution Format Stan-
+dard (BDF V2.1).
+
+The FontProperties are supplied on a font-by-font basis and are returned
+as data in certain X protocol requests as part of the XFontStruct data
+structure. The names and associated data values for each of the Font-
+Properties may also appear as items of the STARTPROPERTIES...ENDPROPER-
+TIES list in the BDF V2.1 specification.
+
+3.1. FontName
+
+Each FontName is logically composed of two strings: a FontNameRegistry
+prefix that is followed by a FontNameSuffix. The FontName uses the ISO
+8859-1 encoding. The FontNameRegistry is an x-registered-name (a name
+that has been registered with the X Consortium) that identifies the reg-
+istration authority that owns the specified FontNameSuffix syntax and
+semantics.
+
+All font names that conform to this specification are to use a Font-
+NameRegistry prefix, which is defined to be the string "-" (HYPHEN).
+All FontNameRegistry prefixes of the form: +version-, where the speci-
+fied version indicates some future XLFD specification, are reserved by
+the X Consortium for future extensions to XLFD font names. If required,
+extensions to the current XLFD font name shall be constructed by append-
+ing new fields to the current structure, each delimited by the existing
+field delimiter. The availability of other FontNameRegistry prefixes or
+
+
+
+ 3
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+fonts that support other registries is server implementation dependent.
+
+In the X protocol specification, the FontName is required to be a
+string; hence, numeric field values are represented in the name as
+string equivalents. All FontNameSuffix fields are also defined as Font-
+Properties; numeric property values are represented as signed or
+unsigned integers, as appropriate.
+
+3.1.1. FontName Syntax
+
+The FontName is a structured, parsable string (of type STRING8) whose
+Backus-Naur Form syntax description is as follows:
+
+ FontName ::= XFontNameRegistry XFontNameSuffix |
+ PrivFontNameRegistry PrivFontNameSuf-
+ fix
+ XFontNameRegistry ::= XFNDelim | XFNExtPrefix Version XFN-
+ Delim
+ XFontNameSuffix ::= FOUNDRY XFNDelim FAMILY_NAME XFNDelim
+ WEIGHT_NAME XFNDelim SLANT XFNDelim
+ SETWIDTH_NAME XFNDelim ADD_
+ STYLE_NAME XFNDelim PIXEL_SIZE XFNDe-
+ lim POINT_SIZE XFNDelim RESOLUTION_X
+ XFNDelim RESOLUTION_Y XFNDelim SPAC-
+ ING XFNDelim AVERAGE_WIDTH XFNDelim
+ CHARSET_REGISTRY XFNDelim
+ CHARSET_ENCODING
+ Version ::= STRING8 - the XLFD version that
+ defines an extension to the font name
+ syntax (for example, "1.4")
+ XFNExtPrefix ::= OCTET - "+" (PLUS)
+ XFNDelim ::= OCTET - "-" (HYPHEN)
+ PrivFontNameRegistry STRING8 - other than those strings
+ ::= reserved by XLFD
+PrivFontNameSuffix ::= STRING8
+
+
+Field values are constructed as strings of ISO 8859-1 graphic charac-
+ters, excluding the following:
+
+o "-" (HYPHEN), the XLFD font name delimiter character
+
+o "?" (QUESTION MARK) and "*" (ASTERISK), the X protocol font name
+ wildcard characters
+
+o "," (COMMA), used by Xlib to separate XLFD font names in a font
+ set.
+
+o """ (QUOTATION MARK), used by some commercial products to quote a
+ font name.
+
+Alphabetic case distinctions are allowed but are for human readability
+concerns only. Conforming X servers will perform matching on font name
+query or open requests independent of case. The entire font name string
+
+
+
+ 4
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+must have no more than 255 characters. It is recommended that clients
+construct font name query patterns by explicitly including all field
+delimiters to avoid unexpected results. Note that SPACE is a valid
+character of a FontName field; for example, the string "ITC Avant Garde
+Gothic" might be a FAMILY_NAME.
+
+3.1.2. FontName Field Definitions
+
+This section discusses the FontName:
+
+o FOUNDRY field
+
+o FAMILY_NAME field
+
+o WEIGHT_NAME field
+
+o SLANT field
+
+o SETWIDTH_NAME field
+
+o ADD_STYLE_NAME field
+
+o PIXEL_SIZE field
+
+o POINT_SIZE field
+
+o RESOLUTION_X and RESOLUTION_Y fields
+
+o SPACING field
+
+o AVERAGE_WIDTH field
+
+o CHARSET_REGISTRY and CHARSET_ENCODING fields
+
+3.1.2.1. FOUNDRY Field
+
+FOUNDRY is an x-registered-name, the name or identifier of the digital
+type foundry that digitized and supplied the font data, or if different,
+the identifier of the organization that last modified the font shape or
+metric information.
+
+The reason this distinction is necessary is that a given font design may
+be licensed from one source (for example, ITC) but digitized and sold by
+any number of different type suppliers. Each digital version of the
+original design, in general, will be somewhat different in metrics and
+shape from the idealized original font data, because each font foundry,
+for better or for worse, has its own standards and practices for tweak-
+ing a typeface for a particular generation of output technologies or has
+its own perception of market needs.
+
+It is up to the type supplier to register with the X Consortium a suit-
+able name for this FontName field according to the registration proce-
+dures defined by the Consortium.
+
+
+
+
+ 5
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+The X Consortium shall define procedures for registering foundry and
+other names and shall maintain and publish, as part of its public dis-
+tribution, a registry of such registered names for use in XLFD font
+names and properties.
+
+
+3.1.2.2. FAMILY_NAME Field
+
+FAMILY_NAME is a string that identifies the range or family of typeface
+designs that are all variations of one basic typographic style. This
+must be spelled out in full, with words separated by spaces, as
+required. This name must be human-understandable and suitable for pre-
+sentation to a font user to identify the typeface family.
+
+It is up to the type supplier to supply and maintain a suitable string
+for this field and font property, to secure the proper legal title to a
+given name, and to guard against the infringement of other's copyrights
+or trademarks. By convention, FAMILY_NAME is not translated. FAM-
+ILY_NAME may include an indication of design ownership if considered a
+valid part of the typeface family name.
+
+The following are examples of FAMILY_NAME:
+
+o Helvetica
+
+o ITC Avant Garde Gothic
+
+o Times
+
+o Times Roman
+
+o Bitstream Amerigo
+
+o Stone
+
+3.1.2.3. WEIGHT_NAME Field
+
+WEIGHT_NAME is a string that identifies the font's typographic weight,
+that is, the nominal blackness of the font, according to the FOUNDRY's
+judgment. This name must be human-understandable and suitable for pre-
+sentation to a font user. The value "0" is used to indicate a polymor-
+phic font (see section 6).
+
+The interpretation of this field is somewhat problematic because the
+typographic judgment of weight has traditionally depended on the overall
+design of the typeface family in question; that is, it is possible that
+the DemiBold weight of one font could be almost equivalent in typo-
+graphic feel to a Bold font from another family.
+
+WEIGHT_NAME is captured as an arbitrary string because it is an impor-
+tant part of a font's complete human-understandable name. However, it
+should not be used for font matching or substitution. For this purpose,
+X client applications should use the weight-related font properties
+(RELATIVE_WEIGHT and WEIGHT) that give the coded relative weight and the
+
+
+
+ 6
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+calculated weight, respectively.
+
+3.1.2.4. SLANT Field
+
+SLANT is a code-string that indicates the overall posture of the type-
+face design used in the font. The encoding is as follows:
+
+---------------------------------------------------------------------------
+Code English Translation Description
+---------------------------------------------------------------------------
+"R" Roman Upright design
+"I" Italic Italic design, slanted clockwise from the
+ vertical
+"O" Oblique Obliqued upright design, slanted clockwise
+ from the vertical
+"RI" Reverse Italic Italic design, slanted counterclockwise
+ from the vertical
+"RO" Reverse Oblique Obliqued upright design, slanted counter-
+ clockwise from the vertical
+"OT" Other Other
+numeric Polymorphic See section 6 on polymorphic font support.
+---------------------------------------------------------------------------
+
+
+The SLANT codes are for programming convenience only and usually are
+converted into their equivalent human-understandable form before being
+presented to a user.
+
+3.1.2.5. SETWIDTH_NAME Field
+
+SETWIDTH_NAME is a string that gives the font's typographic proportion-
+ate width, that is, the nominal width per horizontal unit of the font,
+according to the FOUNDRY's judgment. The value "0" is used to indicate
+a polymorphic font (see section 6).
+
+As with WEIGHT_NAME, the interpretation of this field or font property
+is somewhat problematic, because the designer's judgment of setwidth has
+traditionally depended on the overall design of the typeface family in
+question. For purposes of font matching or substitution, X client
+applications should either use the RELATIVE_SETWIDTH font property that
+gives the relative coded proportionate width or calculate the propor-
+tionate width.
+
+The following are examples of SETWIDTH_NAME:
+
+o Normal
+
+o Condensed
+
+o Narrow
+
+o Double Wide
+
+
+
+
+
+ 7
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.1.2.6. ADD_STYLE_NAME Field
+
+ADD_STYLE_NAME is a string that identifies additional typographic style
+information that is not captured by other fields but is needed to iden-
+tify the particular font. The character "[" anywhere in the field is
+used to indicate a polymorphic font (see section 6).
+
+ADD_STYLE_NAME is not a typeface classification field and is only used
+for uniqueness. Its use, as such, is not limited to typographic style
+distinctions.
+
+The following are examples of ADD_STYLE_NAME:
+
+o Serif
+
+o Sans Serif
+
+o Informal
+
+o Decorated
+
+3.1.2.7. PIXEL_SIZE Field
+
+PIXEL_SIZE gives the body size of the font at a particular POINT_SIZE
+and RESOLUTION_Y. PIXEL_SIZE is either an integer-string or a string
+beginning with "[". A string beginning with "[" represents a matrix
+(see section 4). PIXEL_SIZE usually incorporates additional vertical
+spacing that is considered part of the font design. (Note, however,
+that this value is not necessarily equivalent to the height of the font
+bounding box.) Zero is used to indicate a scalable font (see section
+5).
+
+PIXEL_SIZE usually is used by X client applications that need to query
+fonts according to device-dependent size, regardless of the point size
+or vertical resolution for which the font was designed.
+
+3.1.2.8. POINT_SIZE Field
+
+POINT_SIZE gives the body size for which the font was designed.
+POINT_SIZE is either an integer-string or a string beginning with "[".
+A string beginning with "[" represents a matrix (see section 4). This
+field usually incorporates additional vertical spacing that is consid-
+ered part of the font design. (Note, however, that POINT_SIZE is not
+necessarily equivalent to the height of the font bounding box.)
+POINT_SIZE is expressed in decipoints (where points are as defined in
+the X protocol or 72.27 points equal 1 inch). Zero is used to indicate
+a scalable font (see section 5).
+
+POINT_SIZE and RESOLUTION_Y are used by X clients to query fonts accord-
+ing to device-independent size to maintain constant text size on the
+display regardless of the PIXEL_SIZE used for the font.
+
+
+
+
+
+
+ 8
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.1.2.9. RESOLUTION_X and RESOLUTION_Y Fields
+
+RESOLUTION_X and RESOLUTION_Y are unsigned integer-strings that give the
+horizontal and vertical resolution, measured in pixels or dots per inch
+(dpi), for which the font was designed. Zero is used to indicate a
+scalable font (see section 5). Horizontal and vertical values are
+required because a separate bitmap font must be designed for displays
+with very different aspect ratios (for example, 1:1, 4:3, 2:1, and so
+on).
+
+The separation of pixel or point size and resolution is necessary
+because X allows for servers with very different video characteristics
+(for example, horizontal and vertical resolution, screen and pixel size,
+pixel shape, and so on) to potentially access the same font library.
+The font name, for example, must differentiate between a 14-point font
+designed for 75 dpi (body size of about 14 pixels) or a 14-point font
+designed for 150 dpi (body size of about 28 pixels). Further, in
+servers that implement some or all fonts as continuously scaled and
+scan-converted outlines, POINT_SIZE and RESOLUTION_Y will help the
+server to differentiate between potentially separate font masters for
+text, title, and display sizes or for other typographic considerations.
+
+3.1.2.10. SPACING Field
+
+SPACING is a code-string that indicates the escapement class of the
+font, that is, monospace (fixed pitch), proportional (variable pitch),
+or charcell (a special monospaced font that conforms to the traditional
+data-processing character cell font model). The encoding is as follows:
+
+------------------------------------------------------------------
+Code English Translation Description
+------------------------------------------------------------------
+"P" Proportional A font whose logical character
+ widths vary for each glyph. Note
+ that no other restrictions are
+ placed on the metrics of a propor-
+ tional font.
+"M" Monospaced A font whose logical character
+ widths are constant (that is, every
+ glyph in the font has the same log-
+ ical width). No other restrictions
+ are placed on the metrics of a
+ monospaced font.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 9
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+------------------------------------------------------------------
+Code English Translation Description
+------------------------------------------------------------------
+"C" CharCell A monospaced font that follows the
+ standard typewriter character cell
+ model (that is, the glyphs of the
+ font can be modeled by X clients as
+ "boxes" of the same width and
+ height that are imaged side-by-side
+ to form text strings or top-to-bot-
+ tom to form text lines). By defi-
+ nition, all glyphs have the same
+ logical character width, and no
+ glyphs have "ink" outside of the
+ character cell. There is no kern-
+ ing (that is, on a per-character
+ basis with positive metrics: 0 <=
+ left-bearing <= right-bearing <=
+ width; with negative metrics: width
+ <= left-bearing <= right-bearing <=
+ zero). Also, the vertical extents
+ of the font do not exceed the ver-
+ tical spacing (that is, on a per-
+ character basis: ascent <= font-
+ ascent and descent <= font-
+ descent). The cell height = font-
+ descent + font-ascent, and the
+ width = AVERAGE_WIDTH.
+------------------------------------------------------------------
+
+
+3.1.2.11. AVERAGE_WIDTH Field
+
+AVERAGE_WIDTH is an integer-string typographic metric value that gives
+the unweighted arithmetic mean of the absolute value of the width of
+each glyph in the font (measured in tenths of pixels), multiplied by -1
+if the dominant writing direction for the font is right-to-left. A
+leading "~" (TILDE) indicates a negative value. For monospaced and
+character cell fonts, this is the width of all glyphs in the font. Zero
+is used to indicate a scalable font (see section 5).
+
+3.1.2.12. CHARSET_REGISTRY and CHARSET_ENCODING Fields
+
+The character set used to encode the glyphs of the font (and implicitly
+the font's glyph repertoire), as maintained by the X Consortium charac-
+ter set registry. CHARSET_REGISTRY is an x-registered-name that identi-
+fies the registration authority that owns the specified encoding.
+CHARSET_ENCODING is a registered name that identifies the coded charac-
+ter set as defined by that registration authority and, optionally, a
+subsetting hint.
+
+Although the X protocol does not explicitly have any knowledge about
+character set encodings, it is expected that server implementors will
+prefer to embed knowledge of certain proprietary or standard charsets
+
+
+
+ 10
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+into their font library for reasons of performance and convenience. The
+CHARSET_REGISTRY and CHARSET_ENCODING fields or properties allow an X
+client font request to specify a specific charset mapping in server
+environments where multiple charsets are supported. The availability of
+any particular character set is font and server implementation depen-
+dent.
+
+To prevent collisions when defining character set names, it is recom-
+mended that CHARSET_REGISTRY and CHARSET_ENCODING name pairs be con-
+structed according to the following conventions:
+
+ CharsetRegistry ::= StdCharsetRegistryName | PrivCharsetReg-
+ istryName
+ CharsetEncoding ::= StdCharsetEncodingName | PrivCharsetEn-
+ codingName
+ StdCharsetRegistryName ::= StdOrganizationId StdNumber | StdOrgani-
+ zationId StdNumber Dot Year
+PrivCharsetRegistryName ::= OrganizationId STRING8
+ StdCharsetEncodingName ::= STRING8-numeric part number of refer-
+ enced standard
+PrivCharsetEncodingName ::= STRING8
+ StdOrganizationId ::= STRING8-the registered name or acronym
+ of the referenced standard organization
+ StdNumber ::= STRING8-referenced standard number
+ OrganizationId ::= STRING8-the registered name or acronym
+ of the organization
+ Dot ::= OCTET-"." (FULL STOP)
+ Year ::= STRING8-numeric year (for example, 1989)
+
+
+The X Consortium shall maintain and publish a registry of such character
+set names for use in X protocol font names and properties as specified
+in XLFD.
+
+The ISO Latin-1 character set shall be registered by the X Consortium as
+the CHARSET_REGISTRY-CHARSET_ENCODING value pair: "ISO8859-1".
+
+If the CHARSET_ENCODING contains a "[" (LEFT SQUARE BRACKET), the "["
+and the characters after it up to a "]" (RIGHT SQUARE BRACKET) are a
+subsetting hint telling the font source that the client is interested
+only in a subset of the characters of the font. The font source can,
+optionally, return a font that contains only those characters or any
+superset of those characters. The client can expect to obtain valid
+glyphs and metrics only for those characters, and not for any other
+characters in the font. The font properties may optionally be calcu-
+lated by considering only the characters in the subset.
+
+The BNF for the subsetting hint is
+
+ Subset ::= LeftBracket RangeList RightBracket
+ RangeList ::= Range | Range Space RangeList
+ Range ::= Number | Number Underscore Number
+ Number ::= "0x" HexNumber | DecNumber
+
+
+
+
+ 11
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ HexNumber ::= HexDigit | HexDigit HexNumber
+ DecNumber ::= DecDigit | DecDigit DecNumber
+ DecDigit ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
+ HexDigit ::= DecDigit | "a" | "b" | "c" | "d" | "e" | "f"
+ LeftBracket ::= "[" (LEFT SQUARE BRACKET)
+RightBracket ::= "]" (RIGHT SQUARE BRACKET)
+ Space ::= " " (SPACE)
+ Underscore ::= "_" (LOW LINE)
+
+
+Each Range specifies characters that are to be part of the subset
+included in the font. A Range containing two Numbers specifies the
+first and last character, inclusively, of a range of characters. A
+Range that is a single Number specifies a single character to be
+included in the font. A HexNumber is interpreted as a hexadecimal num-
+ber. A DecNumber is interpreted as a decimal number. The font consists
+of the union of all the Ranges in the RangeList.
+
+For example,
+ -misc-fixed-medium-r-normal--0-0-0-0-c-0-iso8859-1[65 70 80_90]
+tells the font source that the client is interested only in characters
+65, 70, and 80-90.
+
+3.1.3. Examples
+
+The following examples of font names are derived from the screen fonts
+shipped with the X Consortium distribution.
+
+------------------------------------------------------------------------------
+Font X FontName
+------------------------------------------------------------------------------
+75-dpi Fonts
+Charter 12 pt -Bitstream-Charter-Medium-R-Nor-
+ mal--12-120-75-75-P-68-ISO8859-1
+Charter Bold -Bitstream-Charter-Bold-R-Nor-
+12 pt mal--12-120-75-75-P-76-ISO8859-1
+Charter Bold -Bitstream-Charter-Bold-I-Nor-
+Italic 12 pt mal--12-120-75-75-P-75-ISO8859-1
+Charter Italic -Bitstream-Charter-Medium-I-Nor-
+12 pt mal--12-120-75-75-P-66-ISO8859-1
+Courier 8 pt -Adobe-Courier-Medium-R-Normal--8-80-75-75-M-50-ISO8859-1
+Courier 10 pt -Adobe-Courier-Medium-R-Normal--10-100-75-75-M-60-ISO8859-1
+Courier 12 pt -Adobe-Courier-Medium-R-Normal--12-120-75-75-M-70-ISO8859-1
+Courier 24 pt -Adobe-Courier-Medium-R-Normal--24-240-75-75-M-150-ISO8859-1
+Courier Bold -Adobe-Courier-Bold-R-Normal--10-100-75-75-M-60-ISO8859-1
+10 pt
+Courier Bold -Adobe-Courier-Bold-O-Normal--10-100-75-75-M-60-ISO8859-1
+Oblique 10 pt
+Courier -Adobe-Courier-Medium-O-Normal--10-100-75-75-M-60-ISO8859-1
+Oblique 10 pt
+100-dpi Fonts
+Symbol 10 pt -Adobe-Symbol-Medium-R-Normal--14-100-100-100-P-85-Adobe-
+ FONTSPECIFIC
+
+
+
+
+ 12
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+------------------------------------------------------------------------------
+Font X FontName
+------------------------------------------------------------------------------
+Symbol 14 pt -Adobe-Symbol-Medium-R-Normal--20-140-100-100-P-107-Adobe-
+ FONTSPECIFIC
+Symbol 18 pt -Adobe-Symbol-Medium-R-Normal--25-180-100-100-P-142-Adobe-
+ FONTSPECIFIC
+Symbol 24 pt -Adobe-Symbol-Medium-R-Normal--34-240-100-100-P-191-Adobe-
+ FONTSPECIFIC
+Times Bold 10 -Adobe-Times-Bold-R-Normal--14-100-100-100-P-76-ISO8859-1
+pt
+Times Bold -Adobe-Times-Bold-I-Normal--14-100-100-100-P-77-ISO8859-1
+Italic 10 pt
+Times Italic -Adobe-Times-Medium-I-Normal--14-100-100-100-P-73-ISO8859-1
+10 pt
+Times Roman 10 -Adobe-Times-Medium-R-Normal--14-100-100-100-P-74-ISO8859-1
+pt
+------------------------------------------------------------------------------
+
+
+3.2. Font Properties
+
+All font properties are optional but will generally include the font
+name fields and, on a font-by-font basis, any other useful font descrip-
+tive and use information that may be required to use the font intelli-
+gently. The XLFD specifies an extensive set of standard X font proper-
+ties, their interpretation, and fallback rules when the property is not
+defined for a given font. The goal is to provide client applications
+with enough font information to be able to make automatic formatting and
+display decisions with good typographic results.
+
+Font property names use the ISO 8859-1 encoding.
+
+Additional standard X font property definitions may be defined in the
+future and private properties may exist in X fonts at any time. Private
+font properties should be defined to conform to the general mechanism
+defined in the X protocol to prevent overlap of name space and ambiguous
+property names, that is, private font property names are of the form:
+"_" (LOW LINE), followed by the organizational identifier, followed by
+"_" (LOW LINE), and terminated with the property name.
+
+The Backus-Naur Form syntax description of X font properties is as fol-
+lows:
+
+ Properties ::= OptFontPropList
+OptFontPropList ::= NULL | OptFontProp OptFontPropList
+ OptFontProp ::= PrivateFontProp | XFontProp
+PrivateFontProp ::= STRING8 | Underscore OrganizationId
+ Underscore STRING8
+
+
+
+
+
+
+
+
+ 13
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ XFontProp ::= FOUNDRY | FAMILY_NAME | WEIGHT_NAME |
+ SLANT | SETWIDTH_NAME |
+ ADD_STYLE_NAME | PIXEL_SIZE |
+ POINT_SIZE | RESOLUTION_X | RESOLU-
+ TION_Y | SPACING | AVERAGE_WIDTH |
+ CHARSET_REGISTRY | CHARSET_ENCODING |
+ QUAD_WIDTH | RESOLUTION | MIN_SPACE |
+ NORM_SPACE | MAX_SPACE | END_SPACE |
+ SUPERSCRIPT_X | SUPERSCRIPT_Y | SUB-
+ SCRIPT_X | SUBSCRIPT_Y | UNDER-
+ LINE_POSITION | UNDERLINE_THICKNESS |
+ STRIKEOUT_ASCENT | STRIKEOUT_DESCENT
+ | ITALIC_ANGLE | X_HEIGHT | WEIGHT |
+ FACE_NAME | FULL_NAME | FONT | COPY-
+ RIGHT | AVG_CAPITAL_WIDTH | AVG_LOW-
+ ERCASE_WIDTH | RELATIVE_SETWIDTH |
+ RELATIVE_WEIGHT | CAP_HEIGHT | SUPER-
+ SCRIPT_ SIZE | FIGURE_WIDTH | SUB-
+ SCRIPT_SIZE | SMALL_CAP_SIZE | NOTICE
+ | DESTINATION | FONT_TYPE | FONT_VER-
+ SION | RASTERIZER_NAME | RASTER-
+ IZER_VERSION | RAW_ASCENT |
+ RAW_DESCENT | RAW_* | AXIS_NAMES |
+ AXIS_LIMITS | AXIS_TYPES
+ Underscore ::= OCTET-"_" (LOW LINE)
+ OrganizationId ::= STRING8-the registered name of the
+ organization
+
+
+3.2.1. FOUNDRY
+
+FOUNDRY is as defined in the FontName except that the property type is
+ATOM.
+
+FOUNDRY cannot be calculated or defaulted if not supplied as a font
+property.
+
+3.2.2. FAMILY_NAME
+
+FAMILY_NAME is as defined in the FontName except that the property type
+is ATOM.
+
+FAMILY_NAME cannot be calculated or defaulted if not supplied as a font
+property.
+
+3.2.3. WEIGHT_NAME
+
+WEIGHT_NAME is as defined in the FontName except that the property type
+is ATOM.
+
+WEIGHT_NAME can be defaulted if not supplied as a font property, as fol-
+lows:
+
+
+
+
+
+ 14
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ if (WEIGHT_NAME undefined) then
+ WEIGHT_NAME = ATOM("Medium")
+
+
+3.2.4. SLANT
+
+SLANT is as defined in the FontName except that the property type is
+ATOM.
+
+SLANT can be defaulted if not supplied as a font property, as follows:
+
+
+ if (SLANT undefined) then
+ SLANT = ATOM("R")
+
+
+3.2.5. SETWIDTH_NAME
+
+SETWIDTH_NAME is as defined in the FontName except that the property
+type is ATOM.
+
+SETWIDTH_NAME can be defaulted if not supplied as a font property, as
+follows:
+
+
+ if (SETWIDTH_NAME undefined) then
+ SETWIDTH_NAME = ATOM("Normal")
+
+
+3.2.6. ADD_STYLE_NAME
+
+ADD_STYLE_NAME is as defined in the FontName except that the property
+type is ATOM.
+
+ADD_STYLE_NAME can be defaulted if not supplied as a font property, as
+follows:
+
+
+ if (ADD_STYLE_NAME undefined) then
+ ADD_STYLE_NAME = ATOM("")
+
+
+3.2.7. PIXEL_SIZE
+
+PIXEL_SIZE is as defined in the FontName except that the property type
+is INT32.
+
+X clients requiring pixel values for the various typographic fixed spa-
+ces (em space, en space, and thin space) can use the following algorithm
+for computing these values from other properties specified for a font:
+
+
+
+
+
+
+
+ 15
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ DeciPointsPerInch = 722.7
+ EMspace = ROUND ((RESOLUTION_X * POINT_SIZE) / DeciPointsPerInch)
+ ENspace = ROUND (EMspace / 2)
+ THINspace = ROUND (EMspace / 3)
+
+
+where a slash (/) denotes real division, an asterisk (*) denotes real
+multiplication, and ROUND denotes a function that rounds its real argu-
+ment a up or down to the next integer. This rounding is done according
+to X = FLOOR (a + 0.5), where FLOOR is a function that rounds its real
+argument down to the nearest integer.
+
+PIXEL_SIZE can be approximated if not supplied as a font property,
+according to the following algorithm:
+
+
+ DeciPointsPerInch = 722.7
+ if (PIXEL_SIZE undefined) then
+ PIXEL_SIZE = ROUND ((RESOLUTION_Y * POINT_SIZE) / DeciPointsPerInch)
+
+
+3.2.8. POINT_SIZE
+
+POINT_SIZE is as defined in the FontName except that the property type
+is INT32.
+
+X clients requiring device-independent values for em space, en space,
+and thin space can use the following algorithm:
+
+
+ EMspace = ROUND (POINT_SIZE / 10)
+ ENspace = ROUND (POINT_SIZE / 20)
+ THINspace = ROUND (POINT_SIZE / 30)
+
+
+Design POINT_SIZE cannot be calculated or approximated.
+
+3.2.9. RESOLUTION_X
+
+RESOLUTION_X is as defined in the FontName except that the property type
+is CARD32.
+
+RESOLUTION_X cannot be calculated or approximated.
+
+3.2.10. RESOLUTION_Y
+
+RESOLUTION_Y is as defined in the FontName except that the property type
+is CARD32.
+
+RESOLUTION_X cannot be calculated or approximated.
+
+
+
+
+
+
+
+ 16
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.11. SPACING
+
+SPACING is as defined in the FontName except that the property type is
+ATOM.
+
+SPACING can be calculated if not supplied as a font property, according
+to the definitions given above for the FontName.
+
+3.2.12. AVERAGE_WIDTH
+
+AVERAGE_WIDTH is as defined in the FontName except that the property
+type is INT32.
+
+AVERAGE_WIDTH can be calculated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (AVERAGE_WIDTH undefined) then
+ AVERAGE_WIDTH = ROUND (MEAN (ABS (width of each glyph in font)) * 10)
+ * (if (dominant writing direction L-to-R) then 1 else -1)
+
+
+where MEAN is a function that returns the arithmetic mean of its argu-
+ments.
+
+X clients that require values for the number of characters per inch
+(pitch) of a monospaced font can use the following algorithm using the
+AVERAGE_WIDTH and RESOLUTION_X font properties:
+
+
+ if (SPACING not proportional) then
+ CharPitch = (RESOLUTION_X * 10) / AVERAGE_WIDTH
+
+
+3.2.13. CHARSET_REGISTRY
+
+CHARSET_REGISTRY is as defined in the FontName except that the property
+type is ATOM.
+
+CHARSET_REGISTRY cannot be defaulted if not supplied as a font property.
+
+3.2.14. CHARSET_ENCODING
+
+CHARSET_ENCODING is as defined in the FontName except that the property
+type is ATOM.
+
+CHARSET_ENCODING cannot be defaulted if not supplied as a font property.
+
+3.2.15. MIN_SPACE
+
+MIN_SPACE is an integer value (of type INT32) that gives the recommended
+minimum word-space value to be used with this font.
+
+
+
+
+
+ 17
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+MIN_SPACE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (MIN_SPACE undefined) then
+ MIN_SPACE = ROUND(0.75 * NORM_SPACE)
+
+
+3.2.16. NORM_SPACE
+
+NORM_SPACE is an integer value (of type INT32) that gives the recom-
+mended normal word-space value to be used with this font.
+
+NORM_SPACE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+DeciPointsPerInch = 722.7
+if (NORM_SPACE undefined) then
+ if (SPACE glyph exists) then
+ NORM_SPACE = width of SPACE
+ else NORM_SPACE = ROUND((0.33 * RESOLUTION_X * POINT_SIZE)/ DeciPointsPerInch)
+
+
+3.2.17. MAX_SPACE
+
+MAX_SPACE is an integer value (of type INT32) that gives the recommended
+maximum word-space value to be used with this font.
+
+MAX_SPACE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (MAX_SPACE undefined) then
+ MAX_SPACE = ROUND(1.5 * NORM_SPACE)
+
+
+3.2.18. END_SPACE
+
+END_SPACE is an integer value (of type INT32) that gives the recommended
+spacing at the end of sentences.
+
+END_SPACE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (END_SPACE undefined) then
+ END_SPACE = NORM_SPACE
+
+
+3.2.19. AVG_CAPITAL_WIDTH
+
+AVG_CAPITAL_WIDTH is an integer value (of type INT32) that gives the
+unweighted arithmetic mean of the absolute value of the width of each
+
+
+
+ 18
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+capital glyph in the font, in tenths of pixels, multiplied by -1 if the
+dominant writing direction for the font is right-to-left. This property
+applies to both Latin and non-Latin fonts. For Latin fonts, capitals
+are the glyphs A through Z. This property is usually used for font
+matching or substitution.
+
+AVG_CAPITAL_WIDTH can be calculated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (AVG_CAPITAL_WIDTH undefined) then
+ if (capitals exist) then
+ AVG_CAPITAL_WIDTH = ROUND (MEAN
+ (ABS (width of each capital glyph)) * 10)
+ * (if (dominant writing direction L-to-R) then 1 else -1)
+ else AVG_CAPITAL_WIDTH undefined
+
+
+3.2.20. AVG_LOWERCASE_WIDTH
+
+AVG_LOWERCASE_WIDTH is an integer value (of type INT32) that gives the
+unweighted arithmetic mean width of the absolute value of the width of
+each lowercase glyph in the font in tenths of pixels, multiplied by -1
+if the dominant writing direction for the font is right-to-left. For
+Latin fonts, lowercase are the glyphs a through z. This property is
+usually used for font matching or substitution.
+
+Where appropriate, AVG_LOWERCASE_WIDTH can be approximated if not pro-
+vided as a font property, according to the following algorithm:
+
+
+ if (AVG_LOWERCASE_WIDTH undefined) then
+ if (lowercase exists) then
+ AVG_LOWERCASE_WIDTH = ROUND (MEAN
+ (ABS (width of each lowercase glyph)) * 10)
+ * (if (dominant writing direction L-to-R) then 1 else -1)
+ else AVG_LOWERCASE_WIDTH undefined
+
+
+3.2.21. QUAD_WIDTH
+
+QUAD_WIDTH is an integer typographic metric (of type INT32) that gives
+the width of a quad (em) space.
+
+ Note
+
+ Because all typographic fixed spaces (em, en, and thin) are
+ constant for a given font size (that is, they do not vary
+ according to setwidth), the use of this font property has been
+ deprecated. X clients that require typographic fixed space
+ values are encouraged to discontinue use of QUAD_WIDTH and
+ compute these values from other font properties (for example,
+ PIXEL_SIZE). X clients that require a font-dependent width
+ value should use either the FIGURE_WIDTH or one of the average
+
+
+
+ 19
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ character width font properties (AVERAGE_WIDTH, AVG_CAPI-
+ TAL_WIDTH or AVG_LOWERCASE_WIDTH).
+
+
+3.2.22. FIGURE_WIDTH
+
+FIGURE_WIDTH is an integer typographic metric (of type INT32) that gives
+the width of the tabular figures and the dollar sign, if suitable for
+tabular setting (all widths equal). For Latin fonts, these tabular fig-
+ures are the Arabic numerals 0 through 9.
+
+FIGURE_WIDTH can be approximated if not supplied as a font property,
+according to the following algorithm:
+
+
+ if (numerals and DOLLAR sign are defined & widths are equal) then
+ FIGURE_WIDTH = width of DOLLAR
+ else FIGURE_WIDTH property undefined
+
+
+3.2.23. SUPERSCRIPT_X
+
+SUPERSCRIPT_X is an integer value (of type INT32) that gives the recom-
+mended horizontal offset in pixels from the position point to the X ori-
+gin of synthetic superscript text. If the current position point is at
+[X,Y], then superscripts should begin at [X + SUPERSCRIPT_X, Y - SUPER-
+SCRIPT_Y].
+
+SUPERSCRIPT_X can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (SUPERSCRIPT_X undefined) then
+ if (TANGENT(ITALIC_ANGLE) defined) then
+ SUPERSCRIPT_X = ROUND((0.40 * CAP_HEIGHT) / TANGENT(ITALIC_ANGLE))
+ else SUPERSCRIPT_X = ROUND(0.40 * CAP_HEIGHT)
+
+
+where TANGENT is a trigonometric function that returns the tangent of
+its argument, which is in 1/64 degrees.
+
+3.2.24. SUPERSCRIPT_Y
+
+SUPERSCRIPT_Y is an integer value (of type INT32) that gives the recom-
+mended vertical offset in pixels from the position point to the Y origin
+of synthetic superscript text. If the current position point is at
+[X,Y], then superscripts should begin at [X + SUPERSCRIPT_X, Y - SUPER-
+SCRIPT_Y].
+
+SUPERSCRIPT_Y can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+
+
+
+
+ 20
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ if (SUPERSCRIPT_Y undefined) then
+ SUPERSCRIPT_Y = ROUND(0.40 * CAP_HEIGHT)
+
+
+3.2.25. SUBSCRIPT_X
+
+SUBSCRIPT_X is an integer value (of type INT32) that gives the recom-
+mended horizontal offset in pixels from the position point to the X ori-
+gin of synthetic subscript text. If the current position point is at
+[X,Y], then subscripts should begin at [X + SUBSCRIPT_X, Y + SUB-
+SCRIPT_Y].
+
+SUBSCRIPT_X can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (SUBSCRIPT_X undefined) then
+ if (TANGENT(ITALIC_ANGLE) defined) then
+ SUBSCRIPT_X = ROUND((0.40 * CAP_HEIGHT) / TANGENT(ITALIC_ANGLE))
+ else SUBSCRIPT_X = ROUND(0.40 * CAP_HEIGHT)
+
+
+3.2.26. SUBSCRIPT_Y
+
+SUBSCRIPT_Y is an integer value (of type INT32) that gives the recom-
+mended vertical offset in pixels from the position point to the Y origin
+of synthetic subscript text. If the current position point is at [X,Y],
+then subscripts should begin at [X + SUBSCRIPT_X, Y + SUBSCRIPT_Y].
+
+SUBSCRIPT_Y can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (SUBSCRIPT_Y undefined) then
+ SUBSCRIPT_Y = ROUND(0.40 * CAP_HEIGHT)
+
+
+3.2.27. SUPERSCRIPT_SIZE
+
+SUPERSCRIPT_SIZE is an integer value (of type INT32) that gives the rec-
+ommended body size of synthetic superscripts to be used with this font,
+in pixels. This will generally be smaller than the size of the current
+font; that is, superscripts are imaged from a smaller font offset
+according to SUPERSCRIPT_X and SUPERSCRIPT_Y.
+
+SUPERSCRIPT_SIZE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (SUPERSCRIPT_SIZE undefined) then
+ SUPERSCRIPT_SIZE = ROUND(0.60 * PIXEL_SIZE)
+
+
+
+
+
+
+ 21
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.28. SUBSCRIPT_SIZE
+
+SUBSCRIPT_SIZE is an integer value (of type INT32) that gives the recom-
+mended body size of synthetic subscripts to be used with this font, in
+pixels. As with SUPERSCRIPT_SIZE, this will generally be smaller than
+the size of the current font; that is, subscripts are imaged from a
+smaller font offset according to SUBSCRIPT_X and SUBSCRIPT_Y.
+
+SUBSCRIPT_SIZE can be approximated if not provided as a font property,
+according to the algorithm:
+
+
+ if (SUBSCRIPT_SIZE undefined) then
+ SUBSCRIPT_SIZE = ROUND(0.60 * PIXEL_SIZE)
+
+
+3.2.29. SMALL_CAP_SIZE
+
+SMALL_CAP_SIZE is an integer value (of type INT32) that gives the recom-
+mended body size of synthetic small capitals to be used with this font,
+in pixels. Small capitals are generally imaged from a smaller font of
+slightly more weight. No offset [X,Y] is necessary.
+
+SMALL_CAP_SIZE can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (SMALL_CAP_SIZE undefined) then
+ SMALL_CAP_SIZE = ROUND(PIXEL_SIZE * ((X_HEIGHT
+ + ((CAP_HEIGHT - X_HEIGHT) / 3)) / CAP_HEIGHT))
+
+
+3.2.30. UNDERLINE_POSITION
+
+UNDERLINE_POSITION is an integer value (of type INT32) that gives the
+recommended vertical offset in pixels from the baseline to the top of
+the underline. If the current position point is at [X,Y], the top of
+the baseline is given by [X, Y + UNDERLINE_POSITION].
+
+UNDERLINE_POSITION can be approximated if not provided as a font prop-
+erty, according to the following algorithm:
+
+
+ if (UNDERLINE_POSITION undefined) then
+ UNDERLINE_POSITION = ROUND((maximum descent) / 2)
+
+where maximum descent is the maximum descent (below the baseline) in
+pixels of any glyph in the font.
+
+3.2.31. UNDERLINE_THICKNESS
+
+UNDERLINE_THICKNESS is an integer value (of type INT32) that gives the
+recommended underline thickness, in pixels.
+
+
+
+
+ 22
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+UNDERLINE_THICKNESS can be approximated if not provided as a font prop-
+erty, according to the following algorithm:
+
+
+ CapStemWidth = average width of the stems of capitals
+ if (UNDERLINE_THICKNESS undefined) then
+ UNDERLINE_THICKNESS = CapStemWidth
+
+
+3.2.32. STRIKEOUT_ASCENT
+
+STRIKEOUT_ASCENT is an integer value (of type INT32) that gives the ver-
+tical ascent for boxing or voiding glyphs in this font. If the current
+position is at [X,Y] and the string extent is EXTENT, the upper-left
+corner of the strikeout box is at [X, Y - STRIKEOUT_ASCENT] and the
+lower-right corner of the box is at [X + EXTENT, Y + STRIKEOUT_DESCENT].
+
+STRIKEOUT_ASCENT can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (STRIKEOUT_ASCENT undefined)
+ STRIKEOUT_ASCENT = maximum ascent
+
+where maximum ascent is the maximum ascent (above the baseline) in pix-
+els of any glyph in the font.
+
+3.2.33. STRIKEOUT_DESCENT
+
+STRIKEOUT_DESCENT is an integer value (of type INT32) that gives the
+vertical descent for boxing or voiding glyphs in this font. If the cur-
+rent position is at [X,Y] and the string extent is EXTENT, the upper-
+left corner of the strikeout box is at [X, Y - STRIKEOUT_ASCENT] and the
+lower-right corner of the box is at [X + EXTENT, Y + STRIKEOUT_DESCENT].
+
+STRIKEOUT_DESCENT can be approximated if not provided as a font prop-
+erty, according to the following algorithm:
+
+
+ if (STRIKEOUT_DESCENT undefined)
+ STRIKEOUT_DESCENT = maximum descent
+
+where maximum descent is the maximum descent (below the baseline) in
+pixels of any glyph in the font.
+
+3.2.34. ITALIC_ANGLE
+
+ITALIC_ANGLE is an integer value (of type INT32) that gives the nominal
+posture angle of the typeface design, in 1/64 degrees, measured from the
+glyph origin counterclockwise from the three o'clock position.
+
+ITALIC_ANGLE can be defaulted if not provided as a font property,
+according to the following algorithm:
+
+
+
+
+ 23
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ if (ITALIC_ANGLE undefined) then
+ ITALIC_ANGLE = (90 * 64)
+
+
+3.2.35. CAP_HEIGHT
+
+CAP_HEIGHT is an integer value (of type INT32) that gives the nominal
+height of the capital letters contained in the font, as specified by the
+FOUNDRY or typeface designer.
+
+Certain clients require CAP_HEIGHT to compute scale factors and posi-
+tioning offsets for synthesized glyphs where this information or
+designed glyphs are not explicitly provided by the font (for example,
+small capitals, superiors, inferiors, and so on). CAP_HEIGHT is also a
+critical factor in font matching and substitution.
+
+CAP_HEIGHT can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (CAP_HEIGHT undefined) then
+ if (Latin font) then
+ CAP_HEIGHT = XCharStruct.ascent[glyph X]
+ else if (capitals exist) then
+ CAP_HEIGHT = XCharStruct.ascent[some unaccented capital glyph]
+ else CAP_HEIGHT undefined
+
+
+3.2.36. X_HEIGHT
+
+X_HEIGHT is an integer value (of type INT32) that gives the nominal
+height above the baseline of the lowercase glyphs contained in the font,
+as specified by the FOUNDRY or typeface designer.
+
+As with CAP_HEIGHT, X_HEIGHT is required by certain clients to compute
+scale factors for synthesized small capitals where this information is
+not explicitly provided by the font resource. X_HEIGHT is a critical
+factor in font matching and substitution.
+
+X_HEIGHT can be approximated if not provided as a font property, accord-
+ing to the following algorithm:
+
+
+ if (X_HEIGHT undefined) then
+ if (Latin font) then
+ X_HEIGHT = XCharStruct.ascent[glyph x]
+ else if (lowercase exists) then
+ X_HEIGHT = XCharStruct.ascent[some unaccented lc glyph without an ascender]
+ else X_HEIGHT undefined
+
+
+
+
+
+
+
+
+ 24
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.37. RELATIVE_SETWIDTH
+
+RELATIVE_SETWIDTH is an unsigned integer value (of type CARD32) that
+gives the coded proportionate width of the font, relative to all known
+fonts of the same typeface family, according to the type designer's or
+FOUNDRY's judgment.
+
+RELATIVE_SETWIDTH ranges from 10 to 90 or is 0 if undefined or unknown.
+The following reference values are defined:
+
+---------------------------------------------------------------------------
+Code English Translation Description
+---------------------------------------------------------------------------
+0 Undefined Undefined or unknown
+10 UltraCondensed The lowest ratio of average width to height
+20 ExtraCondensed
+30 Condensed Condensed, Narrow, Compressed, ...
+40 SemiCondensed
+50 Medium Medium, Normal, Regular, ...
+60 SemiExpanded SemiExpanded, DemiExpanded, ...
+70 Expanded
+80 ExtraExpanded ExtraExpanded, Wide, ...
+90 UltraExpanded The highest ratio of average width to height
+---------------------------------------------------------------------------
+
+
+RELATIVE_SETWIDTH can be defaulted if not provided as a font property,
+according to the following algorithm:
+
+
+ if (RELATIVE_SETWIDTH undefined) then
+ RELATIVE_SETWIDTH = 50
+
+
+For polymorphic fonts, RELATIVE_SETWIDTH is not necessarily a linear
+function of the font's setwidth axis.
+
+X clients that want to obtain a calculated proportionate width of the
+font (that is, a font-independent way of identifying the proportionate
+width across all fonts and all font vendors) can use the following algo-
+rithm:
+
+
+ SETWIDTH = AVG_CAPITAL_WIDTH / (CAP_HEIGHT * 10)
+
+
+where SETWIDTH is a real number with zero being the narrowest calculated
+setwidth.
+
+3.2.38. RELATIVE_WEIGHT
+
+RELATIVE_WEIGHT is an unsigned integer value (of type CARD32) that gives
+the coded weight of the font, relative to all known fonts of the same
+typeface family, according to the type designer's or FOUNDRY's judgment.
+
+
+
+ 25
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+RELATIVE_WEIGHT ranges from 10 to 90 or is 0 if undefined or unknown.
+The following reference values are defined:
+
+-----------------------------------------------------------------------
+Code English Translation Description
+-----------------------------------------------------------------------
+0 Undefined Undefined or unknown
+10 UltraLight The lowest ratio of stem width to height
+20 ExtraLight
+30 Light
+40 SemiLight SemiLight, Book, ...
+50 Medium Medium, Normal, Regular,...
+60 SemiBold SemiBold, DemiBold, ...
+70 Bold
+80 ExtraBold ExtraBold, Heavy, ...
+90 UltraBold UltraBold, Black, ..., the highest ratio
+ of stem width to height
+-----------------------------------------------------------------------
+
+
+RELATIVE_WEIGHT can be defaulted if not provided as a font property,
+according to the following algorithm:
+
+
+ if (RELATIVE_WEIGHT undefined) then
+ RELATIVE_WEIGHT = 50
+
+
+For polymorphic fonts, RELATIVE_WEIGHT is not necessarily a linear func-
+tion of the font's weight axis.
+
+3.2.39. WEIGHT
+
+Calculated WEIGHT is an unsigned integer value (of type CARD32) that
+gives the calculated weight of the font, computed as the ratio of capi-
+tal stem width to CAP_HEIGHT, in the range 0 to 1000, where 0 is the
+lightest weight.
+
+WEIGHT can be calculated if not supplied as a font property, according
+to the following algorithm:
+
+
+ CapStemWidth = average width of the stems of capitals
+ if (WEIGHT undefined) then
+ WEIGHT = ROUND ((CapStemWidth * 1000) / CAP_HEIGHT)
+
+
+A calculated value for weight is necessary when matching fonts from dif-
+ferent families because both the RELATIVE_WEIGHT and the WEIGHT_NAME are
+assigned by the typeface supplier, according to its tradition and prac-
+tice, and therefore, are somewhat subjective. Calculated WEIGHT pro-
+vides a font-independent way of identifying the weight across all fonts
+and all font vendors.
+
+
+
+
+ 26
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.40. RESOLUTION
+
+RESOLUTION is an integer value (of type INT32) that gives the resolution
+for which this font was created, measured in 1/100 pixels per point.
+
+ Note
+
+ As independent horizontal and vertical design resolution com-
+ ponents are required to accommodate displays with nonsquare
+ aspect ratios, the use of this font property has been depre-
+ cated, and independent RESOLUTION_X and RESOLUTION_Y font name
+ fields/properties have been defined (see sections 3.1.2.9 and
+ 3.1.2.10). X clients are encouraged to discontinue use of the
+ RESOLUTION property and are encouraged to use the appropriate
+ X,Y resolution properties, as required.
+
+
+3.2.41. FONT
+
+FONT is a string (of type ATOM) that gives the full XLFD name of the
+font--that is, the value can be used to open another instance of the
+same font.
+
+If not provided, the FONT property cannot be calculated.
+
+3.2.42. FACE_NAME
+
+FACE_NAME is a human-understandable string (of type ATOM) that gives the
+full device-independent typeface name, including the owner, weight,
+slant, set, and so on but not the resolution, size, and so on. This
+property may be used as feedback during font selection.
+
+FACE_NAME cannot be calculated or approximated if not provided as a font
+property.
+
+3.2.43. FULL_NAME
+
+FULL_NAME is the same as FACE_NAME. Its use is deprecated, but it is
+found on some old fonts.
+
+3.2.44. COPYRIGHT
+
+COPYRIGHT is a human-understandable string (of type ATOM) that gives the
+copyright information of the legal owner of the digital font data.
+
+This information is a required component of a font but is independent of
+the particular format used to represent it (that is, it cannot be cap-
+tured as a comment that could later be thrown away for efficiency rea-
+sons).
+
+COPYRIGHT cannot be calculated or approximated if not provided as a font
+property.
+
+
+
+
+
+ 27
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.45. NOTICE
+
+NOTICE is a human-understandable string (of type ATOM) that gives the
+copyright information of the legal owner of the font design or, if not
+applicable, the trademark information for the typeface FAMILY_NAME.
+
+Typeface design and trademark protection laws vary from country to coun-
+try, the USA having no design copyright protection currently while vari-
+ous countries in Europe offer both design and typeface family name
+trademark protection. As with COPYRIGHT, this information is a required
+component of a font but is independent of the particular format used to
+represent it.
+
+NOTICE cannot be calculated or approximated if not provided as a font
+property.
+
+3.2.46. DESTINATION
+
+DESTINATION is an unsigned integer code (of type CARD32) that gives the
+font design destination, that is, whether it was designed as a screen
+proofing font to match printer font glyph widths (WYSIWYG), as an opti-
+mal video font (possibly with corresponding printer font) for extended
+screen viewing (video text), and so on.
+
+The font design considerations are very different, and at current dis-
+play resolutions, the readability and legibility of these two kinds of
+screen fonts are very different. DESTINATION allows publishing clients
+that use X to model the printed page and video text clients, such as on-
+line documentation browsers, to query for X screen fonts that suit their
+particular requirements.
+
+The encoding is as follows:
+
+--------------------------------------------------------------------
+Code English Translation Description
+--------------------------------------------------------------------
+0 WYSIWYG The font is optimized to match the
+ typographic design and metrics of an
+ equivalent printer font.
+1 Video text The font is optimized for screen leg-
+ ibility and readability.
+--------------------------------------------------------------------
+
+
+
+3.2.47. FONT_TYPE
+
+FONT_TYPE is a human-understandable string (of type ATOM) that describes
+the format of the font data as they are read from permanent storage by
+the current font source. It is a static attribute of the source data.
+It can be used by clients to select a type of bitmap or outline font
+without regard to the rasterizer used to render the font.
+
+
+
+
+
+ 28
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+Predefined values are as follows:
+
+----------------------------------------------------------------
+Value When applicable
+----------------------------------------------------------------
+"Bitmap" Hand-tuned bitmap fonts. Some attempt has been
+ made to optimize the visual appearance of the font
+ for the requested size and resolution.
+"Prebuilt" All bitmap format fonts that cannot be described
+ as "Bitmap", that is, hand-tuned. For example, a
+ bitmap format font that was generated mechanically
+ using a scalable font rasterizer would be consid-
+ ered "Prebuilt", not "Bitmap".
+"Type 1" Any Type 1 font.
+"TrueType" Any TrueType font.
+"Speedo" Any Speedo font.
+"F3" Any F3 font.
+----------------------------------------------------------------
+
+
+Other values may be registered with the X Consortium.
+
+3.2.48. FONT_VERSION
+
+FONT_VERSION is a human-understandable string (of type ATOM) that
+describes the formal or informal version of the font. None is a valid
+value.
+
+3.2.49. RASTERIZER_NAME
+
+RASTERIZER_NAME is a human-understandable string (of type ATOM) that is
+the specific name of the rasterizer that has performed some rasteriza-
+tion operation (such as scaling from outlines) on this font.
+
+To define a RASTERIZER_NAME, the following format is recommended:
+
+RasterizerName ::= OrganizationId Space Rasterizer
+OrganizationId ::= STRING8--the X Registry ORGANIZATION
+ name of the rasterizer implementor or
+ maintainer.
+ Rasterizer ::= the case-sensitive, human-understand-
+ able product name of the rasterizer.
+ Words within this name should be sep-
+ arated by a single SPACE.
+ Space ::= OCTET-" " (SPACE)
+
+
+Examples:
+ X Consortium Bit Scaler
+ X Consortium Type 1 Rasterizer
+ X Consortium Speedo Rasterizer
+ Adobe Type Manager
+ Sun TypeScaler
+
+
+
+
+ 29
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+If RASTERIZER_NAME is not defined, or is None, no rasterization opera-
+tion has been applied to the FONT_TYPE.
+
+3.2.50. RASTERIZER_VERSION
+
+RASTERIZER_VERSION is a human-understandable string (of type ATOM) that
+represents the formal or informal version of a font rasterizer. The
+RASTERIZER_VERSION should match the corresponding product version number
+known to users, when applicable.
+
+3.2.51. RAW_ASCENT
+
+For a font with a transformation matrix, RAW_ASCENT is the font ascent
+in 1000 pixel metrics (see section 4.1).
+
+3.2.52. RAW_DESCENT
+
+For a font with a transformation matrix, RAW_DESCENT is the font descent
+in 1000 pixel metrics (see section 4.1).
+
+3.2.53. RAW_*
+
+For a font with a transformation matrix, all font properties that repre-
+sent horizontal or vertical sizes or displacements will be accompanied
+by a new property, named as the original except prefixed with "RAW_",
+that is computed as described in section 4.1.
+
+3.2.54. AXIS_NAMES
+
+AXIS_NAMES is a list of all the names of the axes for a polymorphic
+font, separated by a null (0) byte. These names are suitable for pre-
+sentation in a user interface (see section 6).
+
+3.2.55. AXIS_LIMITS
+
+AXIS_LIMITS is a list of integers, two for each axis, giving the minimum
+and maximum allowable values for that axis of a polymorphic font (see
+section 6).
+
+3.2.56. AXIS_TYPES
+
+AXIS_TYPES is like AXIS_NAMES, but can be registered as having specific
+semantics (see section 6).
+
+3.3. Built-in Font Property Atoms
+
+The following font property atom definitions were predefined in the ini-
+tial version of the core protocol:
+
+----------------------------------------------
+Font Property/Atom Name Property Type
+----------------------------------------------
+MIN_SPACE INT32
+
+
+
+
+ 30
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+----------------------------------------------
+Font Property/Atom Name Property Type
+----------------------------------------------
+NORM_SPACE INT32
+MAX_SPACE INT32
+END_SPACE INT32
+SUPERSCRIPT_X INT32
+SUPERSCRIPT_Y INT32
+SUBSCRIPT_X INT32
+SUBSCRIPT_Y INT32
+UNDERLINE_POSITION INT32
+UNDERLINE_THICKNESS INT32
+STRIKEOUT_ASCENT INT32
+STRIKEOUT_DESCENT INT32
+FONT_ASCENT INT32
+FONT_DESCENT INT32
+ITALIC_ANGLE INT32
+X_HEIGHT INT32
+QUAD_WIDTH INT32 - deprecated
+WEIGHT CARD32
+POINT_SIZE INT32
+RESOLUTION CARD32 - deprecated
+COPYRIGHT ATOM
+FULL_NAME ATOM - deprecated
+FAMILY_NAME ATOM
+DEFAULT_CHAR CARD32
+----------------------------------------------
+
+
+4. Matrix Transformations
+
+An XLFD name presented to the server can have the POINT_SIZE or
+PIXEL_SIZE field begin with the character "[". If the first character
+of the field is "[", the character must be followed with ASCII represen-
+tations of four floating point numbers and a trailing "]", with white
+space separating the numbers and optional white space separating the
+numbers from the "[" and "]" characters. Numbers use standard floating
+point syntax but use the character "~" to represent a minus sign in the
+mantissa or exponent.
+
+The BNF for a matrix transformation string is as follows:
+
+ MatrixString ::= LeftBracket OptionalSpace Float Space Float Space Float
+ Space Float OptionalSpace RightBracket
+OptionalSpace ::= "" | Space
+ Space ::= SpaceChar | SpaceChar Space
+ Float ::= Mantissa | Mantissa Exponent
+ Mantissa ::= Sign Number | Number
+ Sign ::= Plus | Tilde
+ Number ::= Integer | Integer Dot Integer | Dot Integer
+ Integer ::= Digit | Digit Integer
+ Digit ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
+ Exponent ::= "e" SignedInteger | "E" SignedInteger
+
+
+
+
+ 31
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+SignedInteger ::= Sign Integer | Integer
+ LeftBracket ::= OCTET - "[" (LEFT SQUARE BRACKET)
+ RightBracket ::= OCTET - "]" (RIGHT SQUARE BRACKET)
+ SpaceChar ::= OCTET - " " (SPACE)
+ Tilde ::= OCTET - "~" (TILDE)
+ Plus ::= OCTET - "+" (PLUS)
+ Dot ::= OCTET - "." (FULL STOP)
+
+
+The string "[a b c d]" represents a graphical transformation of the
+glyphs in the font by the matrix
+
+[ a b 0 ]
+[ c d 0 ]
+[ 0 0 1 ]
+
+
+All transformations occur around the origin of the glyph. The relation-
+ship between the current scalar values and the matrix transformation
+values is that the scalar value "N" in the POINT_SIZE field produces the
+same glyphs as the matrix "[N/10 0 0 N/10]" in that field, and the
+scalar value "N" in the PIXEL_SIZE field produces the same glyphs as the
+matrix "[N*RESOLUTION_X/RESOLUTION_Y 0 0 N]" in that field.
+
+If matrices are specified for both the POINT_SIZE and PIXEL_SIZE, they
+must bear the following relationship to each other within an implementa-
+tion-specific tolerance:
+ PIXEL_SIZE_MATRIX = [Sx 0 0 Sy] * POINT_SIZE_MATRIX
+where
+ Sx = RESOLUTION_X / 72.27
+ Sy = RESOLUTION_Y / 72.27
+
+If either the POINT_SIZE or PIXEL_SIZE field is unspecified (either "0"
+or wildcarded), the preceding formulas can be used to compute one from
+the other.
+
+4.1. Metrics and Font Properties
+
+In this section, the phrase "1000 pixel metrics" means the metrics that
+would be obtained if the rasterizer took the base untransformed design
+used to generate the transformed font and scaled it linearly to a height
+of 1000 pixels, with no rotation component. Note that there may be no
+way for the application to actually request this font since the raster-
+izer may use different outlines or rasterization techniques at that size
+from the ones used to generate the transformed font.
+
+Notes on properties and metrics:
+
+The per-char ink metrics (lbearing, rbearing, ascent, and descent) rep-
+resent the ink extent of the transformed glyph around its origin.
+
+The per-char width is the x component of the transformed character
+width.
+
+
+
+
+ 32
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+The font ascent and descent are the y component of the transformed font
+ascent or descent.
+
+The FONT property returns a name reflecting the matrix being used--that
+is, the name returned can be used to open another instance of the same
+font. The returned name is not necessarily an exact copy of the
+requested name. If, for example, the user requests
+ -misc-fixed-medium-r-normal--0-[2e1 0 0.0 +10.0]-72-72-c-0-iso8859-1
+the resulting FONT property might be
+ -misc-fixed-medium-r-normal--[19.9 0 0 10]-[20 0 0
+10]-72-72-c-0-iso8859-1
+The FONT property will always include matrices in both the PIXEL_SIZE
+and the POINT_SIZE fields.
+
+To allow accurate client positioning of transformed characters, the
+attributes field of the XCharInfo contains the width of the character in
+1000 pixel metrics. This attributes field should be interpreted as a
+signed integer.
+
+There will always be 2 new font properties defined, RAW_ASCENT and
+RAW_DESCENT, that hold the ascent and descent in 1000 pixel metrics.
+
+All font properties that represent horizontal widths or displacements
+have as their value the x component of the transformed width or dis-
+placement. All font properties that represent vertical heights or dis-
+placements have as their value the y component of the transformed height
+or displacement. Each such property will be accompanied by a new prop-
+erty, named as the original except prefixed with "RAW_", that gives the
+value of the width, height, or displacement in 1000 pixel metrics.
+
+5. Scalable Fonts
+
+The XLFD is designed to support scalable fonts. A scalable font is a
+font source from which instances of arbitrary size can be derived. A
+scalable font source might be one or more outlines together with zero or
+more hand-tuned bitmap fonts at specific sizes and resolutions, or it
+might be a programmatic description together with zero or more bitmap
+fonts, or some other format (perhaps even just a single bitmap font).
+
+The following definitions are useful for discussing scalable fonts:
+
+Well-formed XLFD pattern
+
+ A pattern string containing 14 hyphens, one of which is the first
+ character of the pattern. Wildcard characters are permitted in the
+ fields of a well-formed XLFD pattern.
+
+Scalable font name
+
+ A well-formed XLFD pattern containing no wildcards and containing
+ the digit "0" in the PIXEL_SIZE, POINT_SIZE, and AVERAGE_WIDTH
+ fields.
+
+
+
+
+
+ 33
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+Scalable fields
+
+ The XLFD fields PIXEL_SIZE, POINT_SIZE, RESOLUTION_X, RESOLUTION_Y,
+ and AVERAGE_WIDTH.
+
+Derived instance
+
+ The result of replacing the scalable fields of a font name with
+ values to yield a font name that could actually be produced from
+ the font source. A scaling engine is permitted, but not required,
+ to interpret the scalable fields in font names to support anamor-
+ phic scaling.
+
+Global list
+
+ The list of names that would be returned by an X server for a List-
+ Fonts protocol request on the pattern "*" if there were no protocol
+ restrictions on the total number of names returned.
+
+
+The global list consists of font names derived from font sources. If a
+single font source can support multiple character sets (specified in the
+CHARSET_REGISTRY and CHARSET_ENCODING fields), each such character set
+should be used to form a separate font name in the list. For a nonscal-
+able font source, the simple font name for each character set is
+included in the global list. For a scalable font source, a scalable
+font name for each character set is included in the list. In addition
+to the scalable font name, specific derived instance names may also be
+included in the list. The relative order of derived instances with
+respect to the scalable font name is not constrained. Finally, font
+name aliases may also be included in the list. The relative order of
+aliases with respect to the real font name is not constrained.
+
+The values of the RESOLUTION_X and RESOLUTION_Y fields of a scalable
+font name are implementation dependent, but to maximize backward compat-
+ibility, they should be reasonable nonzero values, for example, a reso-
+lution close to that provided by the screen (in a single-screen server).
+Because some existing applications rely on seeing a collection of point
+and pixel sizes, server vendors are strongly encouraged in the near term
+to provide a mechanism for including, for each scalable font name, a set
+of specific derived instance names. For font sources that contain a
+collection of hand-tuned bitmap fonts, including names of these
+instances in the global list is recommended and sufficient.
+
+The X protocol request OpenFont on a scalable font name returns a font
+corresponding to an implementation-dependent derived instance of that
+font name.
+
+The X protocol request ListFonts on a well-formed XLFD pattern returns
+the following. Starting with the global list, if the actual pattern
+argument has values containing no wildcards in scalable fields, then
+substitute each such field into the corresponding field in each scalable
+font name in the list. For each resulting font name, if the remaining
+scalable fields cannot be replaced with values to produce a derived
+
+
+
+ 34
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+instance, remove the font name from the list. Now take the modified
+list, and perform a simple pattern match against the pattern argument.
+ListFonts returns the resulting list.
+
+For example, given the global list:
+
+ -Linotype-Times-Bold-I-Normal--0-0-100-100-P-0-ISO8859-1
+ -Linotype-Times-Bold-R-Normal--0-0-100-100-P-0-ISO8859-1
+ -Linotype-Times-Medium-I-Normal--0-0-100-100-P-0-ISO8859-1
+ -Linotype-Times-Medium-R-Normal--0-0-100-100-P-0-ISO8859-1
+
+
+a ListFonts request with the pattern:
+
+
+ -*-Times-*-R-Normal--*-120-100-100-P-*-ISO8859-1
+
+
+would return:
+
+ -Linotype-Times-Bold-R-Normal--0-120-100-100-P-0-ISO8859-1
+ -Linotype-Times-Medium-R-Normal--0-120-100-100-P-0-ISO8859-1
+
+
+ListFonts on a pattern containing wildcards that is not a well-formed
+XLFD pattern is only required to return the list obtained by performing
+a simple pattern match against the global list. X servers are permit-
+ted, but not required, to use a more sophisticated matching algorithm.
+
+6. Polymorphic Fonts
+
+Fonts that can be varied in ways other than size or resolution are
+called polymorphic fonts. Multiple Master Type 1 font programs are one
+type of a polymorphic font. Current examples of axes along which the
+fonts can be varied are width, weight, and optical size; others might
+include formality or x-height.
+
+To support polymorphic fonts, special values indicating variability are
+defined for the following XLFD fields:
+ WEIGHT_NAME
+ SLANT
+ SETWIDTH_NAME
+ ADD_STYLE_NAME
+
+The string "0" is the special polymorphic value. In the WEIGHT_NAME,
+SLANT, or SETWIDTH_NAME field, "0" must be the entire field. There may
+be multiple polymorphic values in the ADD_STYLE_NAME field. They are
+surrounded by "[" and "]" and separated by a Space, as "[0 0]". The
+polymorphic values may coexist with other data in the field. It is rec-
+ommended that the polymorphic values be at the end of the ADD_STYLE_NAME
+field.
+
+The font-matching algorithms for a font with polymorphic fields are
+identical to the matching algorithms for a font with scalable fields.
+
+
+
+ 35
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+There are three new font properties to describe the axes of variation,
+AXIS_NAMES, AXIS_LIMITS, and AXIS_TYPES. AXIS_NAMES is a list of all
+the names of the axes for the font, separated by a null (0) byte. These
+names are suitable for presentation in a user interface. AXIS_LIMITS is
+a list of integers, two for each axis, giving the minimum and maximum
+allowable values for that axis. AXIS_TYPES is like AXIS_NAMES, but can
+be registered as having specific semantics.
+
+The axes are listed in the properties in the same order as they appear
+in the font name. They are matched with font name fields by looking for
+the special polymorphic values in the font name.
+
+Examples:
+
+The Adobe Myriad MM font program has width and weight axes. Weight can
+vary from 215 to 830, and width from 300 to 700.
+
+ Name:
+ -Adobe-Myriad MM-0-R-0--0-0-0-0-P-0-ISO8859-1
+ AXIS_NAMES:
+ Weight, Width
+ AXIS_LIMITS:
+ 215, 830, 300, 700
+ AXIS_TYPES:
+ Adobe-Weight, Adobe-Width
+ Sample derived instance:
+ -Adobe-Myriad MM-412-R-575--*-120-100-100-P-*-ISO8859-1
+
+
+The Adobe Minion MM Italic font program has width, weight, and optical
+size axes.
+
+ Name:
+ -Adobe-Minion MM-0-I-0-[0]-0-0-0-0-P-0-ISO8859-1
+ AXIS_NAMES:
+ Weight, Width, Optical size
+ AXIS_LIMITS:
+ 345, 620, 450, 600, 6, 72
+ AXIS_TYPES:
+ Adobe-Weight, Adobe-Width, Adobe-OpticalSize
+ Sample derived instance:
+ -Adobe-Minion MM-550-I-480-[18]-*-180-100-100-P-*-ISO8859-1
+
+
+The Adobe Minion MM Swash Italic font program has the same axes and val-
+ues. This shows how "[0]" in the ADD_STYLE_NAME field can coexist with
+other words.
+
+ Name:
+ -Adobe-Minion MM-0-I-0-Swash[0]-0-0-0-0-P-0-ISO8859-1
+ AXIS_NAMES:
+ Weight, Width, Optical size
+ AXIS_LIMITS:
+ 345, 620, 450, 600, 6, 72
+
+
+
+ 36
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+ AXIS_TYPES:
+ Adobe-Weight, Adobe-Width, Adobe-OpticalSize
+ Sample derived instance:
+ -Adobe-Minion MM-550-I-480-Swash[18]-*-180-100-100-P-*-ISO8859-1
+
+
+The XYZ Abc font, a hypothetical font, has optical size and x-height
+axes. This shows how there can be more than one polymorphic value in
+the ADD_STYLE_NAME field.
+
+ Name:
+ -XYZ-Abc-Medium-R-Normal-[0 0]-0-0-0-0-P-0-ISO8859-1
+ AXIS_NAMES:
+ Optical size, X-height
+ AXIS_LIMITS:
+ 6, 72, 400, 600
+ AXIS_TYPES:
+ XYZ-OpticalSize, XYZ-Xheight
+ Sample derived instance:
+ -XYZ-Abc-Medium-R-Normal-[14 510]-*-140-100-100-P-*-ISO8859-1
+
+
+If an axis allows negative values, a client requests a negative value by
+using "~" (TILDE) as a minus sign.
+
+Axis types can be registered with the X Consortium, along with their
+semantics.
+
+If a font name that contains the polymorphic value or a wildcard in a
+polymorphic field is presented to a font source, the font source is free
+to substitute any value that is convenient. However, font sources
+should try to use a value that would be considered normal or medium for
+the particular font. For example, if an optical size variable is unre-
+solved, the font source should provide a value appropriate to the size
+of the font.
+
+The result of specifying an out-of-range value for a polymorphic field
+is undefined. The font source may treat this as a BadName error, treat
+the value as if it were the closest legal value, or extrapolate to try
+to accommodate the value.
+
+7. Affected Elements of Xlib and the X Protocol
+
+The following X protocol requests must support the XLFD conventions:
+
+o OpenFont - for the name argument
+
+o ListFonts - for the pattern argument
+
+o ListFontsWithInfo - for the pattern argument
+
+In addition, the following Xlib functions must support the XLFD conven-
+tions:
+
+
+
+
+ 37
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+o XLoadFont - for the name argument
+
+o XListFontsWithInfo - for the pattern argument
+
+o XLoadQueryFont - for the name argument
+
+o XListFonts - for the pattern argument
+
+8. BDF Conformance
+
+The bitmap font distribution and interchange format adopted by the X
+Consortium (BDF V2.1) provides a general mechanism for identifying the
+font name of an X font and a variable list of font properties, but it
+does not mandate the syntax or semantics of the font name or the seman-
+tics of the font properties that might be provided in a BDF font. This
+section identifies the requirements for BDF fonts that conform to XLFD.
+
+8.1. XLFD Conformance Requirements
+
+A BDF font conforms to the XLFD specification if and only if the follow-
+ing conditions are satisfied:
+
+o The value for the BDF item FONT conforms to the syntax and semantic
+ definition of a XLFD FontName string.
+
+o The FontName begins with the X FontNameRegistry prefix: "-".
+
+o All XLFD FontName fields are defined.
+
+o Any FontProperties provided conform in name and semantics to the
+ XLFD FontProperty definitions.
+
+A simple method of testing for conformance would entail verifying that
+the FontNameRegistry prefix is the string "-", that the number of field
+delimiters in the string and coded field values are valid, and that each
+font property name either matches a standard XLFD property name or fol-
+lows the definition of a private property.
+
+8.2. FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR
+
+FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR are provided in the BDF
+specification as properties that are moved to the XFontStruct by the BDF
+font compiler in generating the X server-specific binary font encoding.
+If present, these properties shall comply with the following semantic
+definitions.
+
+8.2.1. FONT_ASCENT
+
+FONT_ASCENT is an integer value (of type INT32) that gives the recom-
+mended typographic ascent above the baseline for determining interline
+spacing. Specific glyphs of the font may extend beyond this. If the
+current position point for line n is at [X,Y], then the origin of the
+next line m = n + 1 (allowing for a possible font change) is [X, Y +
+FONT_DESCENTn + FONT_ASCENTm].
+
+
+
+ 38
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+FONT_ASCENT can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (FONT_ASCENT undefined) then
+ FONT_ASCENT = maximum ascent
+
+where maximum ascent is the maximum ascent (above the baseline) in pix-
+els of any glyph in the font.
+
+8.2.2. FONT_DESCENT
+
+FONT_DESCENT is an integer value (of type INT32) that gives the recom-
+mended typographic descent below the baseline for determining interline
+spacing. Specific glyphs of the font may extend beyond this. If the
+current position point for line n is at [X,Y], then the origin of the
+next line m = n+1 (allowing for a possible font change) is [X, Y +
+FONT_DESCENTn + FONT_ASCENTm].
+
+The logical extent of the font is inclusive between the Y-coordinate
+values: Y - FONT_ASCENT and Y + FONT_DESCENT + 1.
+
+FONT_DESCENT can be approximated if not provided as a font property,
+according to the following algorithm:
+
+
+ if (FONT_DESCENT undefined) then
+ FONT_DESCENT = maximum descent
+
+where maximum descent is the maximum descent (below the baseline) in
+pixels of any glyph in the font.
+
+8.2.3. DEFAULT_CHAR
+
+The DEFAULT_CHAR is an unsigned integer value (of type CARD32) that
+specifies the index of the default character to be used by the X server
+when an attempt is made to display an undefined or nonexistent character
+in the font. (For a font using a 2-byte matrix format, the index bytes
+are encoded in the integer as byte1 * 65536 + byte2.) If the
+DEFAULT_CHAR itself specifies an undefined or nonexistent character in
+the font, then no display is performed.
+
+DEFAULT_CHAR cannot be approximated if not provided as a font property.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 39
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 40
+
+
+
+
+
+
+
+
+
+ Table of Contents
+
+
+1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1
+2. Requirements and Goals . . . . . . . . . . . . . . . . . . . . . 1
+2.1. Provide Unique and Descriptive Font Names . . . . . . . . . . . 2
+2.2. Support Multiple Font Vendors and Character Sets . . . . . . . 2
+2.3. Support Scalable and Polymorphic Fonts . . . . . . . . . . . . 2
+2.4. Support Transformations and Subsetting of Fonts . . . . . . . . 2
+2.5. Be Independent of X Server and Operating or File System
+Implementations . . . . . . . . . . . . . . . . . . . . . . . . . . 2
+2.6. Support Arbitrarily Complex Font Matching and Substitution
+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
+2.7. Be Extensible . . . . . . . . . . . . . . . . . . . . . . . . . 3
+3. X Logical Font Description . . . . . . . . . . . . . . . . . . . 3
+3.1. FontName . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
+3.1.1. FontName Syntax . . . . . . . . . . . . . . . . . . . . . . . 4
+3.1.2. FontName Field Definitions . . . . . . . . . . . . . . . . . 5
+3.1.2.1. FOUNDRY Field . . . . . . . . . . . . . . . . . . . . . . . 5
+3.1.2.2. FAMILY_NAME Field . . . . . . . . . . . . . . . . . . . . . 6
+3.1.2.3. WEIGHT_NAME Field . . . . . . . . . . . . . . . . . . . . . 6
+3.1.2.4. SLANT Field . . . . . . . . . . . . . . . . . . . . . . . . 7
+3.1.2.5. SETWIDTH_NAME Field . . . . . . . . . . . . . . . . . . . . 7
+3.1.2.6. ADD_STYLE_NAME Field . . . . . . . . . . . . . . . . . . . 8
+3.1.2.7. PIXEL_SIZE Field . . . . . . . . . . . . . . . . . . . . . 8
+3.1.2.8. POINT_SIZE Field . . . . . . . . . . . . . . . . . . . . . 8
+3.1.2.9. RESOLUTION_X and RESOLUTION_Y Fields . . . . . . . . . . . 9
+3.1.2.10. SPACING Field . . . . . . . . . . . . . . . . . . . . . . 9
+3.1.2.11. AVERAGE_WIDTH Field . . . . . . . . . . . . . . . . . . . 10
+3.1.2.12. CHARSET_REGISTRY and CHARSET_ENCODING Fields . . . . . . . 10
+3.1.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 12
+3.2. Font Properties . . . . . . . . . . . . . . . . . . . . . . . . 13
+3.2.1. FOUNDRY . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
+3.2.2. FAMILY_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 14
+3.2.3. WEIGHT_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 14
+3.2.4. SLANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
+3.2.5. SETWIDTH_NAME . . . . . . . . . . . . . . . . . . . . . . . . 15
+3.2.6. ADD_STYLE_NAME . . . . . . . . . . . . . . . . . . . . . . . 15
+3.2.7. PIXEL_SIZE . . . . . . . . . . . . . . . . . . . . . . . . . 15
+3.2.8. POINT_SIZE . . . . . . . . . . . . . . . . . . . . . . . . . 16
+3.2.9. RESOLUTION_X . . . . . . . . . . . . . . . . . . . . . . . . 16
+3.2.10. RESOLUTION_Y . . . . . . . . . . . . . . . . . . . . . . . . 16
+3.2.11. SPACING . . . . . . . . . . . . . . . . . . . . . . . . . . 17
+3.2.12. AVERAGE_WIDTH . . . . . . . . . . . . . . . . . . . . . . . 17
+3.2.13. CHARSET_REGISTRY . . . . . . . . . . . . . . . . . . . . . . 17
+3.2.14. CHARSET_ENCODING . . . . . . . . . . . . . . . . . . . . . . 17
+3.2.15. MIN_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 17
+3.2.16. NORM_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18
+3.2.17. MAX_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18
+3.2.18. END_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18
+3.2.19. AVG_CAPITAL_WIDTH . . . . . . . . . . . . . . . . . . . . . 18
+3.2.20. AVG_LOWERCASE_WIDTH . . . . . . . . . . . . . . . . . . . . 19
+3.2.21. QUAD_WIDTH . . . . . . . . . . . . . . . . . . . . . . . . . 19
+
+
+
+ i
+
+
+
+
+
+X Logical Font Description Conventions X11, Release 6.4
+
+
+3.2.22. FIGURE_WIDTH . . . . . . . . . . . . . . . . . . . . . . . . 20
+3.2.23. SUPERSCRIPT_X . . . . . . . . . . . . . . . . . . . . . . . 20
+3.2.24. SUPERSCRIPT_Y . . . . . . . . . . . . . . . . . . . . . . . 20
+3.2.25. SUBSCRIPT_X . . . . . . . . . . . . . . . . . . . . . . . . 21
+3.2.26. SUBSCRIPT_Y . . . . . . . . . . . . . . . . . . . . . . . . 21
+3.2.27. SUPERSCRIPT_SIZE . . . . . . . . . . . . . . . . . . . . . . 21
+3.2.28. SUBSCRIPT_SIZE . . . . . . . . . . . . . . . . . . . . . . . 22
+3.2.29. SMALL_CAP_SIZE . . . . . . . . . . . . . . . . . . . . . . . 22
+3.2.30. UNDERLINE_POSITION . . . . . . . . . . . . . . . . . . . . . 22
+3.2.31. UNDERLINE_THICKNESS . . . . . . . . . . . . . . . . . . . . 22
+3.2.32. STRIKEOUT_ASCENT . . . . . . . . . . . . . . . . . . . . . . 23
+3.2.33. STRIKEOUT_DESCENT . . . . . . . . . . . . . . . . . . . . . 23
+3.2.34. ITALIC_ANGLE . . . . . . . . . . . . . . . . . . . . . . . . 23
+3.2.35. CAP_HEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . 24
+3.2.36. X_HEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . 24
+3.2.37. RELATIVE_SETWIDTH . . . . . . . . . . . . . . . . . . . . . 25
+3.2.38. RELATIVE_WEIGHT . . . . . . . . . . . . . . . . . . . . . . 25
+3.2.39. WEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
+3.2.40. RESOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . 27
+3.2.41. FONT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
+3.2.42. FACE_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 27
+3.2.43. FULL_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 27
+3.2.44. COPYRIGHT . . . . . . . . . . . . . . . . . . . . . . . . . 27
+3.2.45. NOTICE . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
+3.2.46. DESTINATION . . . . . . . . . . . . . . . . . . . . . . . . 28
+3.2.47. FONT_TYPE . . . . . . . . . . . . . . . . . . . . . . . . . 28
+3.2.48. FONT_VERSION . . . . . . . . . . . . . . . . . . . . . . . . 29
+3.2.49. RASTERIZER_NAME . . . . . . . . . . . . . . . . . . . . . . 29
+3.2.50. RASTERIZER_VERSION . . . . . . . . . . . . . . . . . . . . . 30
+3.2.51. RAW_ASCENT . . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.2.52. RAW_DESCENT . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.2.53. RAW_* . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.2.54. AXIS_NAMES . . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.2.55. AXIS_LIMITS . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.2.56. AXIS_TYPES . . . . . . . . . . . . . . . . . . . . . . . . . 30
+3.3. Built-in Font Property Atoms . . . . . . . . . . . . . . . . . 30
+4. Matrix Transformations . . . . . . . . . . . . . . . . . . . . . 31
+4.1. Metrics and Font Properties . . . . . . . . . . . . . . . . . . 32
+5. Scalable Fonts . . . . . . . . . . . . . . . . . . . . . . . . . 33
+6. Polymorphic Fonts . . . . . . . . . . . . . . . . . . . . . . . . 35
+7. Affected Elements of Xlib and the X Protocol . . . . . . . . . . 37
+8. BDF Conformance . . . . . . . . . . . . . . . . . . . . . . . . . 38
+8.1. XLFD Conformance Requirements . . . . . . . . . . . . . . . . . 38
+8.2. FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR . . . . . . . . . . 38
+8.2.1. FONT_ASCENT . . . . . . . . . . . . . . . . . . . . . . . . . 38
+8.2.2. FONT_DESCENT . . . . . . . . . . . . . . . . . . . . . . . . 39
+8.2.3. DEFAULT_CHAR . . . . . . . . . . . . . . . . . . . . . . . . 39
+
+
+
+
+
+
+
+
+
+
+ ii
+
+
--
2.28.0
