improvements of the FPS counter in the HUDLayer

cc/font_atlas.h

 // Copyright 2012 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.
 
 #ifndef CC_FONT_ATLAS_H_
 #define CC_FONT_ATLAS_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 13 matching lines @@
 
 // This class provides basic ability to draw text onto the heads-up display.
 class CC_EXPORT FontAtlas {
 public:
     static scoped_ptr<FontAtlas> create(SkBitmap bitmap, gfx::Rect asciiToRectTable[128], int fontHeight)
     {
         return make_scoped_ptr(new FontAtlas(bitmap, asciiToRectTable, fontHeight));
     }
     ~FontAtlas();
 
+    // Current font height.
+    int fontHeight() const { return m_fontHeight; }
+
     // Draws multiple lines of text where each line of text is separated by '\n'.
     // - Correct glyphs will be drawn for ASCII codes in the range 32-127; any characters
     //   outside that range will be displayed as a default rectangle glyph.
     // - gfx::Size clip is used to avoid wasting time drawing things that are outside the
     //   target canvas bounds.
     // - Should only be called only on the impl thread.
     void drawText(SkCanvas*, const SkPaint&, const std::string& text, const gfx::Point& destPosition, const gfx::Size& clip) const;
 
+    // Gives a text's width and height on the canvas.
+    gfx::Size textSize(const std::string& text);
+
     // Draws the entire atlas at the specified position, just for debugging purposes.
     void drawDebugAtlas(SkCanvas*, const gfx::Point& destPosition) const;
 
 private:
     FontAtlas(SkBitmap, gfx::Rect asciiToRectTable[128], int fontHeight);
 
     void drawOneLineOfTextInternal(SkCanvas*, const SkPaint&, const std::string&, const gfx::Point& destPosition) const;
 
     // The actual texture atlas containing all the pre-rendered glyphs.
     SkBitmap m_atlas;
 
     // The look-up tables mapping ascii characters to their gfx::Rect locations on the atlas.
     gfx::Rect m_asciiToRectTable[128];
 
     int m_fontHeight;
 
     DISALLOW_COPY_AND_ASSIGN(FontAtlas);
 };
 
 }  // namespace cc
 
 #endif  // CC_FONT_ATLAS_H_