File mgp-alpha-channel.diff of Package mgp
---
draw.c | 35 +++++++++++++++++++++++++-
image/image.h | 1
image/new.c | 4 ++
image/zoom.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
4 files changed, 109 insertions(+), 9 deletions(-)
--- a/draw.c
+++ b/draw.c
@@ -1966,6 +1966,13 @@ obj_image_color(image, bimage, d, inithi
return i;
}
+static Pixel impose_pixel(Pixel fore, Pixel back, byte a)
+{
+ return RGB_TO_TRUE(TRUE_RED(fore) * a + TRUE_RED(back) * (255 - a),
+ TRUE_GREEN(fore) * a + TRUE_GREEN(back) * (255 - a),
+ TRUE_BLUE(fore) * a + TRUE_BLUE(back) * (255 - a));
+}
+
static Image *
obj_image_trans(image, x, y)
Image *image;
@@ -1980,6 +1987,7 @@ obj_image_trans(image, x, y)
int trans;
u_int bw, bh, bx, by;
int inithist;
+ byte *alpha = NULL;
if (!COMPLEX_BGIMAGE) {
if (back_color[caching] != xcol.pixel) {
@@ -1999,6 +2007,19 @@ obj_image_trans(image, x, y)
n = RGB_TO_TRUE(xcol.red, xcol.green, xcol.blue);
pl = image->pixlen;
p = image->data;
+ if (image->alpha) {
+ alpha = image->alpha;
+ for (j = 0; j < image->height; j++) {
+ for (i = 0; i < image->width; i++, p += pl) {
+ byte a = *alpha++;
+ if (a == 255)
+ continue;
+ d = impose_pixel(memToVal(p, pl), n, a);
+ valToMem(d, p, pl);
+ }
+ }
+ break;
+ }
for (j = 0; j < image->height; j++) {
for (i = 0; i < image->width; i++, p += pl) {
if (memToVal(p, pl) == d)
@@ -2024,6 +2045,8 @@ obj_image_trans(image, x, y)
}
pl = image->pixlen;
p = image->data + image->width * j * pl;
+ if (image->type == ITRUE && image->alpha)
+ alpha = image->alpha + image->width * j;
bpl = bgpixmap[bgindex].image->pixlen;
pd = -1;
n = 0; /* for lint */
@@ -2040,6 +2063,16 @@ obj_image_trans(image, x, y)
b = bgpixmap[bgindex].image->data +
bgpixmap[bgindex].image->width * by * bpl;
}
+ if (alpha) {
+ byte a = *alpha++;
+ if (a == 255)
+ continue;
+ d = impose_pixel(memToVal(p, pl),
+ memToVal(b, bpl), a);
+ valToMem(d, p, pl);
+ continue;
+ }
+
if (memToVal(p, pl) != trans)
continue;
d = memToVal(b, bpl);
@@ -2099,7 +2132,7 @@ obj_draw_image(target, x, y, obj, page)
}
freeImage(timage);
}
- if (image->trans >= 0)
+ if (image->trans >= 0 || image->alpha)
image = obj_image_trans(image, x, y);
obj->data.image.image = image; /* to free later */
ximageinfo= imageToXImage(display, screen, visual, depth, image,
--- a/image/image.h
+++ b/image/image.h
@@ -90,6 +90,7 @@ typedef struct {
unsigned int depth; /* depth of image in bits if IRGB type */
unsigned int pixlen; /* length of pixel if IRGB type */
byte *data; /* data rounded to full byte for each row */
+ byte *alpha; /* optional alpha channel */
int trans; /* transparent index in rgb */
} Image;
--- a/image/new.c
+++ b/image/new.c
@@ -119,6 +119,7 @@ Image *newBitImage(width, height)
linelen= (width / 8) + (width % 8 ? 1 : 0); /* thanx johnh@amcc.com */
image->data= (unsigned char *)lcalloc(linelen * height);
image->trans = -1;
+ image->alpha = NULL;
return(image);
}
@@ -141,6 +142,7 @@ Image *newRGBImage(width, height, depth)
image->pixlen= pixlen;
image->data= (unsigned char *)lmalloc(width * height * pixlen);
image->trans = -1;
+ image->alpha = NULL;
return(image);
}
@@ -157,6 +159,7 @@ Image *newTrueImage(width, height)
image->depth= 24;
image->pixlen= 3;
image->data= (unsigned char *)lmalloc(width * height * 3);
+ image->alpha = NULL;
image->trans = -1;
return(image);
}
@@ -171,6 +174,7 @@ void freeImageData(image)
if (!TRUEP(image))
freeRGBMapData(&(image->rgb));
lfree(image->data);
+ lfree(image->alpha);
}
void freeImage(image)
--- a/image/zoom.c
+++ b/image/zoom.c
@@ -58,6 +58,7 @@ static void resize_image(oimage, image)
int i, j;
byte *line1, *line2;
byte *destptr;
+ byte *adest = NULL;
unsigned int srclinelen;
unsigned int pixlen;
Pixel v[4];
@@ -68,6 +69,12 @@ static void resize_image(oimage, image)
pixlen= oimage->pixlen;
srclinelen= oimage->width * pixlen;
destptr = image->data;
+ if (oimage->trans != -1 || oimage->alpha) {
+ image->trans = -1;
+ lfree(image->alpha);
+ image->alpha = lmalloc(image->width * image->height);
+ adest = image->alpha;
+ }
cy = 0;
xstep = (double)oimage->width / (double)image->width;
ystep = (double)oimage->height / (double)image->height;
@@ -84,6 +91,8 @@ static void resize_image(oimage, image)
line2 = oimage->data + srclinelen * y2;
cx = 0;
for (i = image->width; i > 0; i--) {
+ byte a[4];
+ memset(a, 0xff, 4);
x1 = cx;
if (x1 >= maxx) {
x1 = x2 = maxx;
@@ -93,9 +102,25 @@ static void resize_image(oimage, image)
xoff = cx - x1;
}
v[0] = memToVal(line1 + pixlen * x1, pixlen);
+ if (v[0] == oimage->trans) {
+ v[0] = 0;
+ a[0] = 0;
+ }
v[1] = memToVal(line1 + pixlen * x2, pixlen);
+ if (v[1] == oimage->trans) {
+ v[1] = 0;
+ a[1] = 0;
+ }
v[2] = memToVal(line2 + pixlen * x1, pixlen);
+ if (v[2] == oimage->trans) {
+ v[2] = 0;
+ a[2] = 0;
+ }
v[3] = memToVal(line2 + pixlen * x2, pixlen);
+ if (v[3] == oimage->trans) {
+ v[3] = 0;
+ a[3] = 0;
+ }
r = (TRUE_RED(v[0]) * (1 - xoff) +
TRUE_RED(v[1]) * xoff) * (1 - yoff) +
(TRUE_RED(v[2]) * (1 - xoff) +
@@ -111,6 +136,21 @@ static void resize_image(oimage, image)
v[0] = rgb8_to_true(r, g, b);
valToMem(v[0], destptr, pixlen);
destptr += pixlen;
+
+ if (adest) {
+ if (oimage->alpha) {
+ byte *alpha1 = oimage->alpha + oimage->width * y1;
+ byte *alpha2 = oimage->alpha + oimage->width * y2;
+ a[0] = alpha1[x1];
+ a[1] = alpha1[x2];
+ a[2] = alpha2[x1];
+ a[3] = alpha2[x2];
+ }
+
+ *adest++ = (byte)((a[0] * (1 - xoff) + a[1] * xoff) * (1 - yoff) +
+ (a[2] * (1 - xoff) + a[3] * xoff) * yoff);
+ }
+
cx += xstep;
}
cy += ystep;
@@ -125,6 +165,7 @@ static Image *reduced_image(oimage, widt
{
Image *dest;
byte *destptr;
+ byte *adest = NULL;
unsigned int srclinelen;
unsigned int i, j;
unsigned int factorx = oimage->width / width;
@@ -145,23 +186,41 @@ static Image *reduced_image(oimage, widt
dest = newTrueImage(width, height);
destptr = dest->data;
+ if (oimage->trans) {
+ dest->alpha = (unsigned char *)lmalloc(width * height);
+ adest = dest->alpha;
+ }
srclinelen = oimage->width * oimage->pixlen;
for (j = 0; j < oimage->height; j += factory) {
for (i = 0; i < oimage->width; i += factorx) {
- unsigned int r, g, b, div, x, y;
+ unsigned int r, g, b, a, div, x, y;
Pixel v;
- r = g = b= 0;
+ r = g = b = a = 0;
div = 0;
for (y = 0; y < factory && j + y < oimage->height; y++) {
byte *src = oimage->data + srclinelen * (j + y);
+ byte *asrc = NULL;
+ if (oimage->alpha)
+ asrc = oimage->alpha + oimage->width * (j + y);
for (x = 0; x < factorx && i + x < oimage->width; x++) {
v = memToVal(src + pixlen * (i + x), pixlen);
- r += TRUE_RED(v);
- g += TRUE_GREEN(v);
- b += TRUE_BLUE(v);
+ if (asrc) {
+ if (*asrc) {
+ r += TRUE_RED(v);
+ g += TRUE_GREEN(v);
+ g += TRUE_BLUE(v);
+ }
+ a += *asrc;
+ asrc++;
+ } else if (v != oimage->trans) {
+ r += TRUE_RED(v);
+ g += TRUE_GREEN(v);
+ b += TRUE_BLUE(v);
+ a += 0xff;
+ }
div++;
}
}
@@ -171,6 +230,8 @@ static Image *reduced_image(oimage, widt
v = rgb8_to_true(r, g, b);
valToMem(v, destptr, pixlen);
destptr += pixlen;
+ if (adest)
+ *adest++ = a / div;
}
}
return dest;
@@ -287,7 +348,7 @@ Image *zoom(oimage, xzoom, yzoom, verbos
case ITRUE:
if (!RGBP(oimage)) {
Image *tmpimage = NULL;
- if (smooth_scaling && oimage->transparent == -1 &&
+ if (smooth_scaling &&
(oimage->width / xwidth > 1 || oimage->height / ywidth > 1)) {
tmpimage = reduced_image(oimage, xwidth, ywidth);
if (tmpimage->width == xwidth && tmpimage->height == ywidth) {
@@ -296,7 +357,7 @@ Image *zoom(oimage, xzoom, yzoom, verbos
}
}
image= newTrueImage(xwidth, ywidth);
- if (smooth_scaling && oimage->transparent == -1) {
+ if (smooth_scaling) {
resize_image(tmpimage ? tmpimage : oimage, image);
if (tmpimage)
freeImage(tmpimage);
@@ -333,7 +394,8 @@ Image *zoom(oimage, xzoom, yzoom, verbos
if (image) {
image->title= dupString(buf);
- image->trans = oimage->trans;
+ if (!image->alpha)
+ image->trans = oimage->trans;
}
lfree((byte *)xindex);
lfree((byte *)yindex);
