1 files changed, 55 insertions, 0 deletions
diff --git a/src/images/SkScaledBitmapSampler.h b/src/images/SkScaledBitmapSampler.h
new file mode 100644
index 0000000..0bb9924
--- /dev/null
+++ b/src/images/SkScaledBitmapSampler.h
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+#ifndef SkScaledBitmapSampler_DEFINED
+#define SkScaledBitmapSampler_DEFINED
+
+#include "SkTypes.h"
+
+class SkBitmap;
+
+class SkScaledBitmapSampler {
+public:
+    SkScaledBitmapSampler(int origWidth, int origHeight, int cellSize);
+    
+    int scaledWidth() const { return fScaledWidth; }
+    int scaledHeight() const { return fScaledHeight; }
+    
+    int srcY0() const { return fY0; }
+    int srcDY() const { return fDY; }
+
+    enum SrcConfig {
+        kGray,  // 1 byte per pixel
+        kIndex, // 1 byte per pixel
+        kRGB,   // 3 bytes per pixel
+        kRGBX,  // 4 byes per pixel (ignore 4th)
+        kRGBA   // 4 bytes per pixel
+    };
+
+    // Given a dst bitmap (with pixels already allocated) and a src-config,
+    // prepares iterator to process the src colors and write them into dst.
+    // Returns false if the request cannot be fulfulled.
+    bool begin(SkBitmap* dst, SrcConfig sc, bool doDither);
+    // call with row of src pixels, for y = 0...scaledHeight-1.
+    // returns true if the row had non-opaque alpha in it
+    bool next(const uint8_t* SK_RESTRICT src);
+
+private:
+    int fScaledWidth;
+    int fScaledHeight;
+
+    int fX0;    // first X coord to sample
+    int fY0;    // first Y coord (scanline) to sample
+    int fDX;    // step between X samples
+    int fDY;    // step between Y samples
+    
+    typedef bool (*RowProc)(void* SK_RESTRICT dstRow,
+                            const uint8_t* SK_RESTRICT src,
+                            int width, int deltaSrc, int y);
+    
+    // setup state
+    char*   fDstRow; // points into bitmap's pixels
+    int     fDstRowBytes;
+    int     fCurrY; // used for dithering
+    int     fSrcPixelSize;  // 1, 3, 4    
+    RowProc fRowProc;
+};
+
+#endif