Re: [XeTeX] \font "":color=FFFFFF produces black, not white glyphs \font "":color=FFFFFF produces black, not white glyphs, re-visited

[Akira Kakuto]

Hi Jonathan,

What's unclear to me -- because I don't remember, if I ever
knew -- is quite why the driver wanted to treat FFFFFF(FF)
specially, and therefore what the implications of removing that
behavior might be.

In dvi.c, 0xFFFFFFFF was used as a sign that the font is not
colored, I don't know why. So opacity range was 0-254.
I simply introduced rgba_used to indicate the font is colored or not:


--- trunk/Build/source/texk/dvipdfm-x/dvi.c    2020-05-26 00:59:53 UTC (rev 
55283)
+++ trunk/Build/source/texk/dvipdfm-x/dvi.c    2020-05-26 13:45:50 UTC (rev 
55284)
@@ -147,6 +147,10 @@
  spt_t size;
  int   source;     /* Source is either DVI or VF */
  uint32_t rgba_color;
+  uint8_t  rgba_used;
+                    /* Indicates that rgba_color is used or not.
+                     * It enables full range of opacity: 0-255.
+                     */
  int      xgs_id;  /* Transparency ExtGState */
  struct tt_longMetrics *hvmt;
  int   ascent;
@@ -180,6 +184,10 @@
  int    used;
  int    native; /* boolean */
  uint32_t rgba_color;   /* only used for native fonts in XeTeX */
+  uint8_t  rgba_used;
+                    /* Indicates that rgba_color is used or not.
+                     * It enables full range of opacity: 0-255.
+                     */
  uint32_t face_index;
  int    layout_dir; /* 1 = vertical, 0 = horizontal */
  int    extend;
@@ -554,6 +562,7 @@
  def_fonts[num_def_fonts].used        = 0;
  def_fonts[num_def_fonts].native      = 0;
  def_fonts[num_def_fonts].rgba_color  = 0xffffffff;
+  def_fonts[num_def_fonts].rgba_used   = 0;
  def_fonts[num_def_fonts].face_index  = 0;
  def_fonts[num_def_fonts].layout_dir  = 0;
  def_fonts[num_def_fonts].extend      = 0x00010000; /* 1.0 */
@@ -599,6 +608,7 @@

  def_fonts[num_def_fonts].layout_dir  = 0;
  def_fonts[num_def_fonts].rgba_color  = 0xffffffff;
+  def_fonts[num_def_fonts].rgba_used   = 0;
  def_fonts[num_def_fonts].extend      = 0x00010000;
  def_fonts[num_def_fonts].slant       = 0;
  def_fonts[num_def_fonts].embolden    = 0;
@@ -606,8 +616,10 @@
  if (flags & XDV_FLAG_VERTICAL)
    def_fonts[num_def_fonts].layout_dir = 1;

-  if (flags & XDV_FLAG_COLORED)
-    def_fonts[num_def_fonts].rgba_color  = get_unsigned_quad(dvi_file);
+  if (flags & XDV_FLAG_COLORED) {
+    def_fonts[num_def_fonts].rgba_color = get_unsigned_quad(dvi_file);
+    def_fonts[num_def_fonts].rgba_used = 1;
+  }

  if (flags & XDV_FLAG_EXTEND)
    def_fonts[num_def_fonts].extend = get_signed_quad(dvi_file);
@@ -1492,8 +1504,9 @@
                                def_fonts[i].point_size);
    }
    loaded_fonts[font_id].rgba_color = def_fonts[i].rgba_color;
-    /* Opacity: 0xff is fully opaque. */
-    if ((loaded_fonts[font_id].rgba_color & 0xff) == 0xff) {
+    loaded_fonts[font_id].rgba_used = def_fonts[i].rgba_used;
+    /* if rgba_used == 0, not a colored font */
+    if (loaded_fonts[font_id].rgba_used == 0) {
      loaded_fonts[font_id].xgs_id = -1;
    } else {
      pdf_obj *xgs_dict;
@@ -1716,7 +1729,7 @@
    yloc[i] = get_buffered_signed_quad();
  }

-  if (font->rgba_color != 0xffffffff) {
+  if (font->rgba_used == 1) {
    pdf_color color;
    pdf_color_rgbcolor(&color,
      (double)((unsigned char)(font->rgba_color >> 24) & 0xff) / 255,
@@ -1787,7 +1800,7 @@
                       glyph_width, font->font_id, -1);
  }

-  if (font->rgba_color != 0xffffffff) {
+  if (font->rgba_used == 1) {
    if (font->xgs_id >= 0) {
      graphics_mode(); 
      pdf_dev_grestore();

Thanks,
Akira