Revert of Delete SkImageDecoder

src/images/SkScaledBitmapSampler.h

Index: src/images/SkScaledBitmapSampler.h
diff --git a/src/images/SkScaledBitmapSampler.h b/src/images/SkScaledBitmapSampler.h
new file mode 100644
index 0000000000000000000000000000000000000000..198dc07572c0dcf9b920ab08504d16814a4e7ec0
--- /dev/null
+++ b/src/images/SkScaledBitmapSampler.h
@@ -0,0 +1,107 @@
+
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SkScaledBitmapSampler_DEFINED
+#define SkScaledBitmapSampler_DEFINED
+
+#include "SkTypes.h"
+#include "SkColor.h"
+#include "SkImageDecoder.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 srcDX() const { return fDX; }
+    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
+        kRGB_565 // 2 bytes per pixel
+    };
+
+    struct Options {
+        bool fDither;
+        bool fPremultiplyAlpha;
+        bool fSkipZeros;
+        explicit Options(const SkImageDecoder &dec)
+            : fDither(dec.getDitherImage())
+            , fPremultiplyAlpha(!dec.getRequireUnpremultipliedColors())
+            , fSkipZeros(dec.getSkipWritingZeroes())
+            { }
+    };
+
+    // 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, const SkImageDecoder& decoder,
+               const SkPMColor* = nullptr);
+    bool begin(SkBitmap* dst, SrcConfig sc, const Options& opts,
+               const SkPMColor* = nullptr);
+    // 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);
+
+    // Like next(), but specifies the y value of the source row, so the
+    // rows can come in any order. If the row is not part of the output
+    // sample, it will be skipped. Only sampleInterlaced OR next should
+    // be called for one SkScaledBitmapSampler.
+    bool sampleInterlaced(const uint8_t* SK_RESTRICT src, int srcY);
+
+    typedef bool (*RowProc)(void* SK_RESTRICT dstRow,
+                            const uint8_t* SK_RESTRICT src,
+                            int width, int deltaSrc, int y,
+                            const SkPMColor[]);
+
+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
+
+#ifdef SK_DEBUG
+    // Keep track of whether the caller is using next or sampleInterlaced.
+    // Only one can be used per sampler.
+    enum SampleMode {
+        kUninitialized_SampleMode,
+        kConsecutive_SampleMode,
+        kInterlaced_SampleMode,
+    };
+
+    SampleMode fSampleMode;
+#endif
+
+    // setup state
+    char*   fDstRow; // points into bitmap's pixels
+    size_t  fDstRowBytes;
+    int     fCurrY; // used for dithering
+    int     fSrcPixelSize;  // 1, 3, 4
+    RowProc fRowProc;
+
+    // optional reference to the src colors if the src is a palette model
+    const SkPMColor* fCTable;
+
+#ifdef SK_DEBUG
+    // Helper class allowing a test to have access to fRowProc.
+    friend class RowProcTester;
+#endif
+};
+
+#endif