When handling overstrikes, try to guess a bit better how overstrike glyphs

Sun May  7 00:00:00 2000  Owen Taylor  <otaylor@redhat.com>

	* modules/basic/basic.c (basic_engine_shape): When
	handling overstrikes, try to guess a bit better
	how overstrike glyphs are positioned in the font.
	(Now works with more of glyphs from clearlyu, though
	not the Hebrew accents in that font)

	* examples/HELLO.utf8: Insert tab characters to
	keep the columns in the right order for either
	global direction. Insert left-to-right marks in
	a few places to keep leading and trailing punctuation
	in the right place.

	* modules/basic/basic.c (basic_engine_shape): Don't
	show RLM and LRM

	* pango/glyphstring.c (pango_glyph_string_extents): Use
	the logical width set in the glyph string rather than
	that from the font's metrics.

	* pango/pangox.c (pango_x_render): Treat glyph index
	0 as special - representing invisible, 0 size
	character. We need this sometimes, and it is
	easier and faster to have this special case
	than to shape a space.

	* pango/pango-context.c (pango_itemize): Put
	tabs into separate items. (Sort of lame hack,
	we do this to make line breaking with tab
	handling simpler)

	* examples/viewer.c (checkbutton_toggled): Notify
	all the layouts that the context has changed so
	the RTL base dir change actually takes effect.

2 files changed, 22 insertions, 18 deletions

diff --git a/modules/basic/basic-x.c b/modules/basic/basic-x.c
index 6c851228..e78aa384 100644
--- a/modules/basic/basic-x.c
+++ b/modules/basic/basic-x.c
@@ -401,16 +401,9 @@ basic_engine_shape (PangoFont        *font,
 	    input = buf;
 	  }
 
-      if (wc == 0x200B)		/* Zero-width space */
+      if (wc == 0x200B || wc == 0x200E || wc == 0x200F)	/* Zero-width characters */
 	{
-	  index = find_char (cache, font, ' ', input);
-	  if (index)
-	    {
-	      set_glyph (font, glyphs, i, p - text, index);
-	      glyphs->glyphs[i].geometry.width = 0;
-	    }
-	  else
-	    set_glyph (font, glyphs, i, p - text, pango_x_get_unknown_glyph (font));
+	  set_glyph (font, glyphs, i, p - text, 0);
 	}
       else
 	{
@@ -423,10 +416,19 @@ basic_engine_shape (PangoFont        *font,
 		{
 		  if (i > 0)
 		    {
+		      PangoRectangle logical_rect, ink_rect;
+		      
 		      glyphs->glyphs[i].geometry.width = MAX (glyphs->glyphs[i-1].geometry.width,
 							      glyphs->glyphs[i].geometry.width);
 		      glyphs->glyphs[i-1].geometry.width = 0;
 		      glyphs->log_clusters[i] = glyphs->log_clusters[i-1];
+
+		      /* Some heuristics to try to guess how overstrike glyphs are
+		       * done and compensate
+		       */
+		      pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, &ink_rect, &logical_rect);
+		      if (logical_rect.width == 0 && ink_rect.x == 0)
+			glyphs->glyphs[i].geometry.x_offset = (glyphs->glyphs[i].geometry.width - ink_rect.width) / 2;
 		    }
 		}
 	    }
diff --git a/modules/basic/basic.c b/modules/basic/basic.c
index 6c851228..e78aa384 100644
--- a/modules/basic/basic.c
+++ b/modules/basic/basic.c
@@ -401,16 +401,9 @@ basic_engine_shape (PangoFont        *font,
 	    input = buf;
 	  }
 
-      if (wc == 0x200B)		/* Zero-width space */
+      if (wc == 0x200B || wc == 0x200E || wc == 0x200F)	/* Zero-width characters */
 	{
-	  index = find_char (cache, font, ' ', input);
-	  if (index)
-	    {
-	      set_glyph (font, glyphs, i, p - text, index);
-	      glyphs->glyphs[i].geometry.width = 0;
-	    }
-	  else
-	    set_glyph (font, glyphs, i, p - text, pango_x_get_unknown_glyph (font));
+	  set_glyph (font, glyphs, i, p - text, 0);
 	}
       else
 	{
@@ -423,10 +416,19 @@ basic_engine_shape (PangoFont        *font,
 		{
 		  if (i > 0)
 		    {
+		      PangoRectangle logical_rect, ink_rect;
+		      
 		      glyphs->glyphs[i].geometry.width = MAX (glyphs->glyphs[i-1].geometry.width,
 							      glyphs->glyphs[i].geometry.width);
 		      glyphs->glyphs[i-1].geometry.width = 0;
 		      glyphs->log_clusters[i] = glyphs->log_clusters[i-1];
+
+		      /* Some heuristics to try to guess how overstrike glyphs are
+		       * done and compensate
+		       */
+		      pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, &ink_rect, &logical_rect);
+		      if (logical_rect.width == 0 && ink_rect.x == 0)
+			glyphs->glyphs[i].geometry.x_offset = (glyphs->glyphs[i].geometry.width - ink_rect.width) / 2;
 		    }
 		}
 	    }