Draw text via Skia in RenderTextLinux.

ui/gfx/render_text_linux.cc

Index: ui/gfx/render_text_linux.cc
===================================================================
--- ui/gfx/render_text_linux.cc	(revision 112492)
+++ ui/gfx/render_text_linux.cc	(working copy)
@@ -6,10 +6,12 @@
 
 #include <pango/pangocairo.h>
 #include <algorithm>
+#include <vector>
 
 #include "base/i18n/break_iterator.h"
 #include "base/logging.h"
 #include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/font.h"
 #include "ui/gfx/pango_util.h"
 #include "unicode/uchar.h"
 #include "unicode/ustring.h"
@@ -260,27 +262,80 @@
 }
 
 void RenderTextLinux::DrawVisualText(Canvas* canvas) {
-  Rect bounds(display_rect());
+  DCHECK(layout_);
 
-  // Clip the canvas to the text display area.
-  SkCanvas* canvas_skia = canvas->GetSkCanvas();
+  Point offset(ToViewPoint(Point()));
+  // TODO(msw): Establish a vertical baseline for strings of mixed font heights.
+  size_t height = default_style().font.GetHeight();
 
-  skia::ScopedPlatformPaint scoped_platform_paint(canvas_skia);
-  cairo_t* cr = scoped_platform_paint.GetPlatformSurface();
-  cairo_save(cr);
-  cairo_rectangle(cr, bounds.x(), bounds.y(), bounds.width(), bounds.height());
-  cairo_clip(cr);
+  SkScalar x = SkIntToScalar(offset.x());
+  SkScalar y = SkIntToScalar(offset.y());
+  // Center the text vertically in the display area.
+  y += (display_rect().height() - height) / 2;
+  // Offset by the font size to account for Skia expecting y to be the bottom.
+  y += default_style().font.GetFontSize();
 
-  int text_width, text_height;
-  pango_layout_get_pixel_size(layout_, &text_width, &text_height);
-  Point offset(ToViewPoint(Point()));
-  // Vertically centered.
-  int text_y = offset.y() + ((bounds.height() - text_height) / 2);
-  // TODO(xji): need to use SkCanvas->drawPosText() for gpu acceleration.
-  cairo_move_to(cr, offset.x(), text_y);
-  pango_cairo_show_layout(cr, layout_);
+  std::vector<SkPoint> pos;
+  std::vector<uint16> glyphs;
 
-  cairo_restore(cr);
+  internal::SkiaTextRenderer renderer(canvas);
+  renderer.Init();
+
+  for (GSList* it = current_line_->runs; it; it = it->next) {
+    PangoLayoutRun* run = reinterpret_cast<PangoLayoutRun*>(it->data);
+    size_t run_start = Utf8IndexToUtf16Index(run->item->offset);
+
+    // Find the initial style for this run.
+    StyleRanges::const_iterator style = style_ranges().begin();
+    StyleRanges::const_iterator next = style + 1;
+    while (next < style_ranges().end() && next->range.start() <= run_start)
+      style = next++;
+
+    int glyph_count = run->glyphs->num_glyphs;
+    glyphs.resize(glyph_count);
+    pos.resize(glyph_count);
+
+    PangoFontDescription* native_font =
+        pango_font_describe(run->item->analysis.font);
+    renderer.SetFont(gfx::Font(native_font));
+    pango_font_description_free(native_font);
+
+    SkScalar glyph_x = x;
+    SkScalar start_x = x;
+    int start = 0;
+    for (int i = 0; i < glyph_count; ++i) {
+      const PangoGlyphInfo& glyph = run->glyphs->glyphs[i];
+      glyphs[i] = static_cast<uint16>(glyph.glyph);
+      pos[i].set(glyph_x + PANGO_PIXELS(glyph.geometry.x_offset),
+                 y + PANGO_PIXELS(glyph.geometry.y_offset));
+      glyph_x += PANGO_PIXELS(glyph.geometry.width);
+
+      // If this glyph is the last for the current style, draw the glyphs so far
+      // and advance the style iterator.
+      if (run_start + i >= style->range.end()) {

[Alexei Svitkine (slow), 2011/12/02 16:19:59]

There was an error here where the logic was using the glyph index rather than
the character index when comparing against the style range. I've fixed this in
the new patch.

+        renderer.SetForegroundColor(style->foreground);
+        renderer.DrawPosText(&pos[start], &glyphs[start], i - start);
+        if (style->strike || style->underline) {
+          renderer.DrawDecorations(start_x, y, glyph_x - start_x,
+                                   style->underline, style->strike);
+        }
+
+        ++style;
+        start = i;
+        start_x = glyph_x;
+      }
+    }
+
+    // Draw the remaining glyphs.
+    renderer.SetForegroundColor(style->foreground);
+    renderer.DrawPosText(&pos[start], &glyphs[start], glyph_count - start);
+    if (style->strike || style->underline) {
+       renderer.DrawDecorations(start_x, y, glyph_x - start_x,
+                                style->underline, style->strike);
+    }
+
+    x = glyph_x;
+  }
 }
 
 size_t RenderTextLinux::IndexOfAdjacentGrapheme(size_t index, bool next) {
@@ -564,8 +619,8 @@
 
     const Font& font = i->font;
     // In Pango, different fonts means different runs, and it breaks Arabic
-    // shaping acorss run boundaries. So, set font only when it is different
-    // from the default faont.
+    // shaping across run boundaries. So, set font only when it is different
+    // from the default font.
     // TODO(xji): we'll eventually need to split up StyleRange into components
     // (ColorRange, FontRange, etc.) so that we can combine adjacent ranges
     // with the same Fonts (to avoid unnecessarily splitting up runs)