File xournal-fix-strokes-on-Lenovo-active-pen.patch of Package xournal

 ChangeLog          |  6 ++++++
 src/xo-clipboard.c |  2 ++
 src/xo-file.c      |  5 +++++
 src/xo-paint.c     | 35 +++++++++++++++++++++++++++++++++--
 src/xournal.h      |  1 +
 5 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7c6d8c6..8fd18f1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+This version:
+  - keep selection in clipboard after exiting
+  - config option to fix unreliable stroke origin (Lenovo AES pen issues)
+     (use in conjunction with xsetwacom to set RawSample = 1 or 2 until
+      wacom driver fix is committed).
+
 Version 0.4.8.2016 (July 20, 2017 bugfix release):
  * Bug fixes:
   - pen and touchscreen input handling bugfixes (bug #136 and others)
diff --git a/src/xo-clipboard.c b/src/xo-clipboard.c
index 253605e..d998648 100644
--- a/src/xo-clipboard.c
+++ b/src/xo-clipboard.c
@@ -189,6 +189,8 @@ void selection_to_clip(void)
   gtk_clipboard_set_with_data(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD), 
        targets, n_targets,
        callback_clipboard_get, callback_clipboard_clear, sel);
+  gtk_clipboard_set_can_store(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD),
+       targets, n_targets);
   gtk_target_table_free(targets, n_targets);
 }
 
diff --git a/src/xo-file.c b/src/xo-file.c
index 0285b2b..4b8b5b2 100644
--- a/src/xo-file.c
+++ b/src/xo-file.c
@@ -1767,6 +1767,7 @@ void init_config_default(void)
   ui.autosave_delay = 5;
   ui.autosave_loop_running = FALSE;
   ui.autosave_need_catchup = FALSE;
+  ui.fix_stroke_origin = FALSE;
   
   // the default UI vertical order
   ui.vertical_order[0][0] = 1; 
@@ -1917,6 +1918,9 @@ void save_config_to_file(void)
   update_keyval("general", "buttons_switch_mappings",
     _(" buttons 2 and 3 switch mappings instead of drawing (useful for some tablets) (true/false)"),
     g_strdup(ui.button_switch_mapping?"true":"false"));
+  update_keyval("general", "fix_stroke_origin",
+    _(" fix origin of strokes (devices with unreliable button press coordinates, e.g. Lenovo's AES pens) (true/false)"),
+    g_strdup(ui.fix_stroke_origin?"true":"false"));
   update_keyval("general", "autoload_pdf_xoj",
     _(" automatically load filename.pdf.xoj instead of filename.pdf (true/false)"),
     g_strdup(ui.autoload_pdf_xoj?"true":"false"));
@@ -2337,6 +2341,7 @@ void load_config_from_file(void)
   if (parse_keyval_string("general", "touchscreen_device_name", &str))
     if (str!=NULL) ui.device_for_touch = str;
   parse_keyval_boolean("general", "buttons_switch_mappings", &ui.button_switch_mapping);
+  parse_keyval_boolean("general", "fix_stroke_origin", &ui.fix_stroke_origin);
   parse_keyval_boolean("general", "autoload_pdf_xoj", &ui.autoload_pdf_xoj);
   parse_keyval_boolean("general", "autocreate_new_xoj", &ui.autocreate_new_xoj);
   parse_keyval_boolean("general", "autosave_enabled", &ui.autosave_enabled);
diff --git a/src/xo-paint.c b/src/xo-paint.c
index 2331ff7..cf9614b 100644
--- a/src/xo-paint.c
+++ b/src/xo-paint.c
@@ -258,7 +258,7 @@ void continue_stroke(GdkEvent *event)
   } 
   
   get_pointer_coords(event, pt+2);
-  
+
   if (ui.cur_item->brush.variable_width) {
     realloc_cur_widths(ui.cur_path.num_points);
     pressure = get_pressure_multiplier(event);
@@ -308,8 +308,34 @@ void abort_stroke(void)
   ui.cur_item_type = ITEM_NONE;
 }
 
+#define HOOK_MAX_ANGLE_COS 0.9
+
+gboolean fix_origin_if_needed(double *pt)
+{
+  double dotproduct,len1,len2;
+  dotproduct = (pt[2]-pt[0])*(pt[4]-pt[2]) + (pt[3]-pt[1])*(pt[5]-pt[3]);
+  len1 = hypot(pt[2]-pt[0],pt[3]-pt[1]);
+  len2 = hypot(pt[4]-pt[2],pt[5]-pt[3]);
+  if (dotproduct < HOOK_MAX_ANGLE_COS * len1 * len2) {
+    // straighten
+/*
+    if (dotproduct > 0 && len2 > EPSILON) {
+      pt[0] = pt[2]-dotproduct*(pt[4]-pt[2])/len2/len2;
+      pt[1] = pt[3]-dotproduct*(pt[5]-pt[3])/len2/len2;
+    } else */
+    {
+      pt[0] = pt[2];
+      pt[1] = pt[3];
+    }
+    return TRUE;
+  }
+  return FALSE;
+}
+
 void finalize_stroke(void)
 {
+  gboolean need_refresh = FALSE;
+  
   if (ui.cur_path.num_points == 1) { // GnomeCanvas doesn't like num_points=1
     ui.cur_path.coords[2] = ui.cur_path.coords[0]+0.1;
     ui.cur_path.coords[3] = ui.cur_path.coords[1];
@@ -317,6 +343,11 @@ void finalize_stroke(void)
     ui.cur_item->brush.variable_width = FALSE;
   }
   
+  /* fix AES pen mess on Lenovo X1 Yoga 2nd gen and similar... */
+  if (ui.fix_stroke_origin && ui.cur_path.num_points > 2) {
+    need_refresh = fix_origin_if_needed(ui.cur_path.coords);
+  }
+  
   if (!ui.cur_item->brush.variable_width)
     subdivide_cur_path(); // split the segment so eraser will work
 
@@ -330,7 +361,7 @@ void finalize_stroke(void)
   update_item_bbox(ui.cur_item);
   ui.cur_path.num_points = 0;
 
-  if (!ui.cur_item->brush.variable_width) {
+  if (!ui.cur_item->brush.variable_width || need_refresh) {
     // destroy the entire group of temporary line segments
     gtk_object_destroy(GTK_OBJECT(ui.cur_item->canvas_item));
     // make a new line item to replace it
diff --git a/src/xournal.h b/src/xournal.h
index 3599e77..d49cdfc 100644
--- a/src/xournal.h
+++ b/src/xournal.h
@@ -271,6 +271,7 @@ typedef struct UIData {
   gboolean touch_as_handtool; // always map touch device to hand tool?
   gboolean pen_disables_touch; // pen proximity should disable touch device?
   gboolean in_proximity;
+  gboolean fix_stroke_origin; // fix for devices with bad button-press coords?
   char *device_for_touch;
   int which_mouse_button; // the mouse button drawing the current path
   int which_unswitch_button; // if button_switch_mapping, the mouse button that switched the mapping