Fix handling of boxes drawn in do_path mode. Previously we were doing one

2006-12-04  Behdad Esfahbod  <behdad@gnome.org>

        * pango/pangocairo-render.c (_pango_cairo_renderer_draw_frame),
        (_pango_cairo_renderer_draw_box_glyph),
        (_pango_cairo_renderer_draw_unknown_glyph):
        Fix handling of boxes drawn in do_path mode.  Previously we were
        doing one rectangle and stroke it if in show mode, and leave it alone
        if in path mode.  That doesn't really work.  Now we do two rectangles,
        for the outer and inner rects of the box border, but with different
        orientations, such that pango_cairo_layout_path(); cairo_fill(); works
        for hexboxes now.

2 files changed, 66 insertions, 21 deletions

diff --git a/ChangeLog b/ChangeLog
index 31277ad6..7303cfc4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2006-12-04  Behdad Esfahbod  <behdad@gnome.org>
 
+	* pango/pangocairo-render.c (_pango_cairo_renderer_draw_frame),
+	(_pango_cairo_renderer_draw_box_glyph),
+	(_pango_cairo_renderer_draw_unknown_glyph):
+	Fix handling of boxes drawn in do_path mode.  Previously we were
+	doing one rectangle and stroke it if in show mode, and leave it alone
+	if in path mode.  That doesn't really work.  Now we do two rectangles,
+	for the outer and inner rects of the box border, but with different
+	orientations, such that pango_cairo_layout_path(); cairo_fill(); works
+	for hexboxes now.
+
+2006-12-04  Behdad Esfahbod  <behdad@gnome.org>
+
 	Red Hat Bug 211964: [ta] Rendering issue with Tamil
 	Patch from LingNing Zhang
 
diff --git a/pango/pangocairo-render.c b/pango/pangocairo-render.c
index dec4077c..da145400 100644
--- a/pango/pangocairo-render.c
+++ b/pango/pangocairo-render.c
@@ -58,6 +58,48 @@ set_color (PangoCairoRenderer *crenderer,
 			  color->blue / 65535.);
 }
 
+/* modifies cairo_set_line_width() without doing cairo_save/restore() */
+static void
+_pango_cairo_renderer_draw_frame (PangoCairoRenderer *crenderer,
+				  double              x,
+				  double              y,
+				  double              width,
+				  double              height,
+				  double              line_width)
+{
+  if (crenderer->do_path)
+    {
+      cairo_t *cr = crenderer->cr;
+      double d2 = line_width * .5, d = line_width;
+
+      /* we draw an outer box in one winding direction and an inner one in the
+       * opposite direction.  This works for both cairo windings rules.
+       *
+       * what we really want is cairo_stroke_to_path().
+       */
+
+      /* outer */
+      cairo_move_to (cr, x - d2, y - d2);
+      cairo_rel_line_to (cr, width + d, 0);
+      cairo_rel_line_to (cr, 0, height + d);
+      cairo_rel_line_to (cr, - (width + d), 0);
+      cairo_close_path (cr);
+
+      /* inner */
+      cairo_move_to (cr, x + d2, y + d2);
+      cairo_rel_line_to (cr, 0, height - d);
+      cairo_rel_line_to (cr, width - d, 0);
+      cairo_rel_line_to (cr, 0, - (height - d));
+      cairo_close_path (cr);
+    }
+  else
+    {
+      cairo_rectangle (crenderer->cr, x, y, width, height);
+      cairo_set_line_width (crenderer->cr, line_width);
+      cairo_stroke (crenderer->cr);
+    }
+}
+
 static void
 _pango_cairo_renderer_draw_box_glyph (PangoCairoRenderer *crenderer,
 				      PangoGlyphInfo     *gi,
@@ -69,17 +111,13 @@ _pango_cairo_renderer_draw_box_glyph (PangoCairoRenderer *crenderer,
   cairo_save (crenderer->cr);
   cairo_get_current_point (crenderer->cr, &temp_x, &temp_y);
 
-  cairo_rectangle (crenderer->cr,
-		   cx + 1.5,
-		   cy + 1.5 - PANGO_UNKNOWN_GLYPH_HEIGHT,
-		   (double)gi->geometry.width / PANGO_SCALE - 3.0,
-		   PANGO_UNKNOWN_GLYPH_HEIGHT - 3.0);
 
-  if (!crenderer->do_path)
-    {
-      cairo_set_line_width (crenderer->cr, 1.0);
-      cairo_stroke (crenderer->cr);
-    }
+  _pango_cairo_renderer_draw_frame (crenderer,
+				    cx + 1.5,
+				    cy + 1.5 - PANGO_UNKNOWN_GLYPH_HEIGHT,
+				    (double)gi->geometry.width / PANGO_SCALE - 3.0,
+				    PANGO_UNKNOWN_GLYPH_HEIGHT - 3.0,
+				    1.0);
 
   cairo_move_to (crenderer->cr, temp_x, temp_y);
   cairo_restore (crenderer->cr);
@@ -118,17 +156,12 @@ _pango_cairo_renderer_draw_unknown_glyph (PangoCairoRenderer *crenderer,
   cols = (ch > 0xffff ? 6 : 4) / rows;
   g_snprintf (buf, sizeof(buf), (ch > 0xffff) ? "%06X" : "%04X", ch);
 
-  cairo_rectangle (crenderer->cr,
-		   cx + hbi->pad_x * 1.5,
-		   cy + hbi->box_descent - hbi->box_height + hbi->pad_y * 0.5,
-		   (double)gi->geometry.width / PANGO_SCALE - 3 * hbi->pad_x,
-		   (hbi->box_height - hbi->pad_y));
-
-  if (!crenderer->do_path)
-    {
-      cairo_set_line_width (crenderer->cr, hbi->line_width);
-      cairo_stroke (crenderer->cr);
-    }
+  _pango_cairo_renderer_draw_frame (crenderer,
+				    cx + hbi->pad_x * 1.5,
+				    cy + hbi->box_descent - hbi->box_height + hbi->pad_y * 0.5,
+				    (double)gi->geometry.width / PANGO_SCALE - 3 * hbi->pad_x,
+				    (hbi->box_height - hbi->pad_y),
+				    hbi->line_width);
 
   x0 = cx + hbi->pad_x * 3.0;
   y0 = cy + hbi->box_descent - hbi->pad_y * 2;