Transparency

chrome/common/gfx/chrome_canvas_win.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/common/gfx/chrome_canvas.h"
 
 #include <limits>
 
 #include "base/gfx/rect.h"
 #include "base/logging.h"
@@ skipping 140 matching lines @@
 
   ReleaseDC(NULL, dc);
 }
 
 void ChromeCanvas::DrawStringInt(const std::wstring& text, HFONT font,
                                  const SkColor& color, int x, int y, int w,
                                  int h, int flags) {
   if (!IntersectsClipRectInt(x, y, w, h))
     return;
 
-  getTopPlatformDevice().prepareForGDI(x, y, w, h);
   RECT text_bounds = { x, y, x + w, y + h };
   HDC dc = beginPlatformPaint();
   SetBkMode(dc, TRANSPARENT);
   HFONT old_font = (HFONT)SelectObject(dc, font);
   COLORREF brush_color = RGB(SkColorGetR(color), SkColorGetG(color),
                              SkColorGetB(color));
   SetTextColor(dc, brush_color);
 
   int f = ComputeFormatFlags(flags, text);
   DoDrawText(dc, text, &text_bounds, f);
   endPlatformPaint();
 
   // Restore the old font. This way we don't have to worry if the caller
   // deletes the font and the DC lives longer.
   SelectObject(dc, old_font);
-  getTopPlatformDevice().postProcessGDI(x, y, w, h);
+
+  // Windows will have cleared the alpha channel of the text we drew. Assume
+  // we're drawing to an opaque surface, or at least the text rect area is
+  // opaque.
+  getTopPlatformDevice().makeOpaque(x, y, w, h);
 }
 
 void ChromeCanvas::DrawStringInt(const std::wstring& text,
                                  const ChromeFont& font,
                                  const SkColor& color,
                                  int x, int y,
                                  int w, int h) {
   DrawStringInt(text, font, color, x, y, w, h,
                 l10n_util::DefaultCanvasTextAlignment());
 }
 
 void ChromeCanvas::DrawStringInt(const std::wstring& text,
                                  const ChromeFont& font,
                                  const SkColor& color,
                                  int x, int y, int w, int h, int flags) {
   DrawStringInt(text, font.hfont(), color, x, y, w, h, flags);
 }