add size limit for using glyphcache. above that, draw using paths

include/core/SkPaint.h

Index: include/core/SkPaint.h
diff --git a/include/core/SkPaint.h b/include/core/SkPaint.h
index a6c9bd4d198112e8f88e60ff5de8db16cbb68c72..06a3eb0e475a4a57af7d9b9b42e97a9904c2a40e 100644
--- a/include/core/SkPaint.h
+++ b/include/core/SkPaint.h
@@ -13,6 +13,7 @@
 
 #include "SkColor.h"
 #include "SkDrawLooper.h"
+#include "SkMatrix.h"
 #include "SkXfermode.h"
 #ifdef SK_BUILD_FOR_ANDROID
 #include "SkPaintOptionsAndroid.h"
@@ -30,7 +31,6 @@ struct SkRect;
 class SkGlyphCache;
 class SkImageFilter;
 class SkMaskFilter;
-class SkMatrix;
 class SkPath;
 class SkPathEffect;
 struct SkPoint;
@@ -935,6 +935,22 @@ public:
     const SkRect& doComputeFastBounds(const SkRect& orig, SkRect* storage,
                                       Style) const;
 
+    /**
+     *  Return a matrix that applies the paint's text values: size, scale, skew
+     */
+    static SkMatrix* SetTextMatrix(SkMatrix* matrix, SkScalar size,
+                                   SkScalar scaleX, SkScalar skewX) {
+        matrix->setScale(size * scaleX, size);
+        if (skewX) {
+            matrix->postSkew(skewX, 0);
+        }
+        return matrix;
+    }
+    
+    SkMatrix* setTextMatrix(SkMatrix* matrix) const {
+        return SetTextMatrix(matrix, fTextSize, fTextScaleX, fTextSkewX);
+    }
+    
     SkDEVCODE(void toString(SkString*) const;)
 
 private:
@@ -989,8 +1005,31 @@ private:
     static void Term();
 
     enum {
-        kCanonicalTextSizeForPaths = 64
+        /*  This is the size we use when we ask for a glyph's path. We then
+         *  post-transform it as we draw to match the request.
+         *  This is done to try to re-use cache entries for the path.
+         */
+        kCanonicalTextSizeForPaths  = 64,
+
+        /*
+         *  Above this size (taking into account CTM and textSize), we never use
+         *  the cache for bits or metrics (we might overflow), so we just ask
+         *  for a caononical size and post-transform that.
+         */
+        kMaxSizeForGlyphCache       = 256,

[bungeman-skia, 2013/06/04 14:27:58]

It seems odd that these two numbers would be different. This seems to mean that
we go for a smaller size once hitting 256. I suppose it shouldn't make much
difference, it just seems odd.

[reed1, 2013/06/04 15:58:22]

update comment.

     };
+
+    static bool TooBigToUseCache(const SkMatrix& ctm, const SkMatrix& textM);
+
+    bool tooBigToUseCache() const;
+    bool tooBigToUseCache(const SkMatrix& ctm) const;
+
+    static SkScalar MaxCacheSize2() {
+        static const SkScalar kMaxSize = SkIntToScalar(kMaxSizeForGlyphCache);
+        static const SkScalar kMag2Max = kMaxSize * kMaxSize;
+        return kMag2Max;
+    }
+
     friend class SkAutoGlyphCache;
     friend class SkCanvas;
     friend class SkDraw;