Bug 347146 – underline/overstrike spaces

2006-09-11  Behdad Esfahbod  <behdad@gnome.org>

        Bug 347146 – underline/overstrike spaces

        * pango/pango-renderer.c (add_underline), (add_strikethrough),
        (pango_renderer_draw_layout_line): Use logical extents for
        x and width of underline/strikethrough, such that trailing spaces are
        correctly handled.

        * pango/pango-layout.c (pango_layout_run_get_extents): Use logical
        rect for underline/strikethrough, and reflect that in run ink extents.

        * pango/pango-layout.c (pango_layout_line_get_extents): Don't
        let runs with empty ink extents affect total ink extents.

2 files changed, 63 insertions, 27 deletions

diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index 456ca648..1389e000 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -47,6 +47,7 @@ struct _Extents
 struct _ItemProperties
 {
   PangoUnderline  uline;
+  gboolean        strikethrough;
   gint            rise;
   gint            letter_spacing;
   gboolean        shape_set;
@@ -3960,6 +3961,9 @@ pango_layout_run_get_extents (PangoLayoutRun *run,
   if (!run_logical && run->item->analysis.centered_baseline)
     run_logical = &logical;
 
+  if (!run_logical && (properties.uline != PANGO_UNDERLINE_NONE || properties.strikethrough))
+    run_logical = &logical;
+
   if (properties.shape_set)
     imposed_extents (run->item->num_chars,
 		     properties.shape_ink_rect,
@@ -3969,33 +3973,55 @@ pango_layout_run_get_extents (PangoLayoutRun *run,
     pango_glyph_string_extents (run->glyphs, run->item->analysis.font,
 				run_ink, run_logical);
 
-  if (properties.uline != PANGO_UNDERLINE_NONE)
+  if (run_ink && (properties.uline != PANGO_UNDERLINE_NONE || properties.strikethrough))
     {
       PangoFontMetrics *metrics = pango_font_get_metrics (run->item->analysis.font,
 							  run->item->analysis.language); 
       int underline_thickness = pango_font_metrics_get_underline_thickness (metrics);
       int underline_position = pango_font_metrics_get_underline_position (metrics);
+      int strikethrough_thickness = pango_font_metrics_get_strikethrough_thickness (metrics);
+      int strikethrough_position = pango_font_metrics_get_strikethrough_position (metrics);
+
+      int new_pos;
+
+      /* the underline/strikethrough takes x,width of logical_rect.  reflect
+       * that into ink_rect.
+       */
+      new_pos = MIN (run_ink->x, run_logical->x);
+      run_ink->width = MAX (run_ink->x + run_ink->width, run_logical->x + run_logical->width) - new_pos;
+      run_ink->x = new_pos;
+
+      /* We should better handle the case of height==0 in the following cases.
+       * If run_ink->height == 0, we should adjust run_ink->y appropriately.
+       */
+
+      if (properties.strikethrough)
+        {
+	  if (run_ink->height == 0)
+	    {
+	      run_ink->height = strikethrough_thickness;
+	      run_ink->y = -strikethrough_position;
+	    }
+	}
 
       switch (properties.uline)
 	{
 	case PANGO_UNDERLINE_ERROR:
-	  if (run_ink)
-	    run_ink->height = MAX (run_ink->height,
-				   3 * underline_thickness - underline_position - run_ink->y);
+	  run_ink->height = MAX (run_ink->height,
+				 3 * underline_thickness - underline_position - run_ink->y);
 	  break;
 	case PANGO_UNDERLINE_SINGLE:
-	  if (run_ink)
-	    run_ink->height = MAX (run_ink->height,
-				   underline_thickness - underline_position - run_ink->y);
+	  run_ink->height = MAX (run_ink->height,
+				 underline_thickness - underline_position - run_ink->y);
 	  break;
 	case PANGO_UNDERLINE_DOUBLE:
-	  if (run_ink)
-	    run_ink->height = MAX (run_ink->height,
-				   3 * underline_thickness - underline_position - run_ink->y);
+	  run_ink->height = MAX (run_ink->height,
+				 3 * underline_thickness - underline_position - run_ink->y);
 	  break;
 	case PANGO_UNDERLINE_LOW:
-	  if (run_ink)
-	    run_ink->height += 2 * underline_thickness;
+	  run_ink->height += 2 * underline_thickness;
+	  break;
+	case PANGO_UNDERLINE_NONE:
 	  break;
 	default:
 	  g_critical ("unknown underline mode");
@@ -4073,11 +4099,12 @@ pango_layout_line_get_extents (PangoLayoutLine *line,
       
       if (ink_rect)
 	{
-	  if (tmp_list == line->runs)
+	  if (ink_rect->width == 0 || ink_rect->height == 0)
 	    {
 	      *ink_rect = run_ink;
+	      ink_rect->x += x_pos;
 	    }
-	  else
+	  else if (run_ink.width != 0 && run_ink.height != 0)
 	    {
 	      new_pos = MIN (ink_rect->x, x_pos + run_ink.x);
 	      ink_rect->width = MAX (ink_rect->x + ink_rect->width,
@@ -4390,6 +4417,7 @@ pango_layout_get_item_properties (PangoItem      *item,
   GSList *tmp_list = item->analysis.extra_attrs;
 
   properties->uline = PANGO_UNDERLINE_NONE;
+  properties->strikethrough = FALSE;
   properties->letter_spacing = 0;
   properties->rise = 0;
   properties->shape_set = FALSE;
@@ -4406,6 +4434,10 @@ pango_layout_get_item_properties (PangoItem      *item,
 	  properties->uline = ((PangoAttrInt *)attr)->value;
 	  break;
 
+	case PANGO_ATTR_STRIKETHROUGH:
+	  properties->strikethrough = ((PangoAttrInt *)attr)->value;
+	  break;
+	  
         case PANGO_ATTR_RISE:
 	  properties->rise = ((PangoAttrInt *)attr)->value;
           break;
diff --git a/pango/pango-renderer.c b/pango/pango-renderer.c
index f54e1282..7d165f82 100644
--- a/pango/pango-renderer.c
+++ b/pango/pango-renderer.c
@@ -289,7 +289,8 @@ add_underline (PangoRenderer    *renderer,
 	       PangoFontMetrics *metrics,
 	       int               base_x,
 	       int               base_y,
-	       PangoRectangle   *ink_rect)
+	       PangoRectangle   *ink_rect,
+	       PangoRectangle   *logical_rect)
 {
   PangoRectangle *current_rect = &state->underline_rect;
   PangoRectangle new_rect;
@@ -297,8 +298,8 @@ add_underline (PangoRenderer    *renderer,
   int underline_thickness = pango_font_metrics_get_underline_thickness (metrics);
   int underline_position = pango_font_metrics_get_underline_position (metrics);
 
-  new_rect.x = base_x + ink_rect->x;
-  new_rect.width = ink_rect->width;
+  new_rect.x = base_x + logical_rect->x;
+  new_rect.width = logical_rect->width;
   new_rect.height = underline_thickness;
   new_rect.y = base_y;
   
@@ -316,14 +317,13 @@ add_underline (PangoRenderer    *renderer,
       new_rect.y += ink_rect->y + ink_rect->height + underline_thickness;
       break;
     }
+      int new_pos;
   
   if (renderer->underline == state->underline &&
       new_rect.y == current_rect->y &&
       new_rect.height == current_rect->height)
     {
-      current_rect->y = new_rect.y;
       current_rect->width = new_rect.x + new_rect.width - current_rect->x;
-      current_rect->height = new_rect.height;
     }
   else
     {
@@ -340,7 +340,8 @@ add_strikethrough (PangoRenderer    *renderer,
 		   PangoFontMetrics *metrics,
 		   int               base_x,
 		   int               base_y,
-		   PangoRectangle   *ink_rect)
+		   PangoRectangle   *ink_rect,
+		   PangoRectangle   *logical_rect)
 {
   PangoRectangle *current_rect = &state->strikethrough_rect;
   PangoRectangle new_rect;
@@ -348,8 +349,8 @@ add_strikethrough (PangoRenderer    *renderer,
   int strikethrough_thickness = pango_font_metrics_get_strikethrough_thickness (metrics);
   int strikethrough_position = pango_font_metrics_get_strikethrough_position (metrics);
   
-  new_rect.x = base_x + ink_rect->x;
-  new_rect.width = ink_rect->width;
+  new_rect.x = base_x + logical_rect->x;
+  new_rect.width = logical_rect->width;
   new_rect.y = base_y - strikethrough_position;
   new_rect.height = strikethrough_thickness;
   
@@ -357,9 +358,7 @@ add_strikethrough (PangoRenderer    *renderer,
       new_rect.y == current_rect->y &&
       new_rect.height == current_rect->height)
     {
-      current_rect->y = new_rect.y;
       current_rect->width = new_rect.x + new_rect.width - current_rect->x;
-      current_rect->height = new_rect.height;
     }
   else
     {
@@ -493,13 +492,18 @@ pango_renderer_draw_layout_line (PangoRenderer    *renderer,
 	{
 	  ink_rect = shape_attr->ink_rect;
 	  logical_rect = shape_attr->logical_rect;
+	  ink = &ink_rect;
+	  logical = &logical_rect;
 	  glyph_string_width = shape_attr->logical_rect.width;
 	}
       else
 	{
 	  if (renderer->underline != PANGO_UNDERLINE_NONE ||
 	      renderer->strikethrough)
-	    ink = &ink_rect;
+	    {
+	      ink = &ink_rect;
+	      logical = &logical_rect;
+	    }
 	  pango_glyph_string_extents (run->glyphs, run->item->analysis.font,
 				      ink, logical);
 	  if (logical)
@@ -550,12 +554,12 @@ pango_renderer_draw_layout_line (PangoRenderer    *renderer,
 	  if (renderer->underline != PANGO_UNDERLINE_NONE)
 	    add_underline (renderer, &state,metrics,
 			   x + x_off, y - rise,
-			   &ink_rect);
+			   ink, logical);
 	  
 	  if (renderer->strikethrough)
 	    add_strikethrough (renderer, &state, metrics,
 			       x + x_off, y - rise,
-			       &ink_rect);
+			       ink, logical);
 	  
 	  pango_font_metrics_unref (metrics);
 	}