grab from latest android
git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gl/SkGLTextCache.h b/src/gl/SkGLTextCache.h
new file mode 100644
index 0000000..eb552aa
--- /dev/null
+++ b/src/gl/SkGLTextCache.h
@@ -0,0 +1,86 @@
+#ifndef SkGLTextCache_DEFINED
+#define SkGLTextCache_DEFINED
+
+#include "SkGL.h"
+
+class SkGlyph;
+
+class SkGLTextCache {
+public:
+ SkGLTextCache();
+ ~SkGLTextCache();
+
+ /** Delete all of the strikes in the cache. Pass true if the texture IDs are
+ still valid, in which case glDeleteTextures will be called. Pass false
+ if they are invalid (e.g. the gl-context has changed), in which case
+ they will just be abandoned.
+ */
+ void deleteAllStrikes(bool texturesAreValid);
+
+ class Strike {
+ public:
+ int width() const { return fStrikeWidth; }
+ int height() const { return fStrikeHeight; }
+ GLuint texture() const { return fTexName; }
+ int widthShift() const { return fStrikeWidthShift; }
+ int heightShift() const { return fStrikeHeightShift; }
+
+ // call this to force us to ignore the texture name in our destructor
+ // only call it right before our destructor
+ void abandonTexture() { fTexName = 0; }
+
+ private:
+ // if next is non-null, its height must match our height
+ Strike(Strike* next, int width, int height);
+ ~Strike();
+
+ Strike* findGlyph(const SkGlyph&, int* offset);
+ Strike* addGlyphAndBind(const SkGlyph&, const uint8_t*, int* offset);
+
+ enum {
+ kMinStrikeWidth = 1024,
+ kMaxGlyphCount = 256
+ };
+
+ Strike* fNext;
+ GLuint fTexName;
+ uint32_t fGlyphIDArray[kMaxGlyphCount]; // stores glyphIDs
+ uint16_t fGlyphOffsetX[kMaxGlyphCount]; // stores x-offsets
+ uint16_t fGlyphCount;
+ uint16_t fNextFreeOffsetX;
+ uint16_t fStrikeWidth;
+ uint16_t fStrikeHeight;
+ uint8_t fStrikeWidthShift; // pow2(fStrikeWidth)
+ uint8_t fStrikeHeightShift; // pow2(fStrikeHeight)
+
+ friend class SkGLTextCache;
+ };
+
+ /** If found, returns the exact strike containing it (there may be more than
+ one with a given height), and sets offset to the offset for that glyph
+ (if not null). Does NOT bind the texture.
+ If not found, returns null and ignores offset param.
+ */
+ Strike* findGlyph(const SkGlyph&, int* offset);
+
+ /** Adds the specified glyph to this list of strikes, returning the new
+ head of the list. If offset is not null, it is set to the offset
+ for this glyph within the strike. The associated texture is bound
+ to the gl context.
+ */
+ Strike* addGlyphAndBind(const SkGlyph&, const uint8_t image[], int* offset);
+
+private:
+ enum {
+ // greater than this we won't cache
+ kMaxGlyphHeightShift = 9,
+
+ kMaxGlyphHeight = 1 << kMaxGlyphHeightShift,
+ kMaxStrikeListCount = kMaxGlyphHeightShift + 1
+ };
+
+ // heads of the N families, one for each pow2 height
+ Strike* fStrikeList[kMaxStrikeListCount];
+};
+
+#endif