Scanline decoding for gifs

src/codec/SkCodecPriv.h

 /*
  * Copyright 2015 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCodecPriv_DEFINED
 #define SkCodecPriv_DEFINED
 
@@ skipping 13 matching lines @@
     uint8_t maxAlpha = 0xFF;
 
 #define UPDATE_RESULT_ALPHA(alpha)              \
     zeroAlpha |= (alpha);                       \
     maxAlpha  &= (alpha);
 
 #define COMPUTE_RESULT_ALPHA                    \
     SkSwizzler::GetResult(zeroAlpha, maxAlpha);
 
 /*
+ * returns a scaled dimension based on the original dimension and the sampleSize
+ * NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder
+ */
+static int get_scaled_dimension(int srcDimension, int sampleSize) {
+    if (sampleSize > srcDimension) {
+        return 1;
+    }
+    return srcDimension / sampleSize;
+}
+
+/*
  * Returns the first coordinate that we will keep during a scaled decode.
  * The output can be interpreted as an x-coordinate or a y-coordinate.
  *
  * This does not need to be called and is not called when sampleFactor == 1.
  */
 static int get_start_coord(int sampleFactor) { return sampleFactor / 2; };
 
 /*
  * Given a coordinate in the original image, this returns the corresponding
  * coordinate in the scaled image.  This function is meaningless if
@@ skipping 86 matching lines @@
 /*
  *
  * Copy the codec color table back to the client when kIndex8 color type is requested
  */
 static inline void copy_color_table(const SkImageInfo& dstInfo, SkColorTable* colorTable,
         SkPMColor* inputColorPtr, int* inputColorCount) {
     if (kIndex_8_SkColorType == dstInfo.colorType()) {
         SkASSERT(nullptr != inputColorPtr);
         SkASSERT(nullptr != inputColorCount);
         SkASSERT(nullptr != colorTable);
-        memcpy(inputColorPtr, colorTable->readColors(), *inputColorCount * 4);
+        memcpy(inputColorPtr, colorTable->readColors(), *inputColorCount * sizeof(SkPMColor));
     }
 }
 
 /*
  * Compute row bytes for an image using pixels per byte
  */
 static inline size_t compute_row_bytes_ppb(int width, uint32_t pixelsPerByte) {
     return (width + pixelsPerByte - 1) / pixelsPerByte;
 }
 
@@ skipping 72 matching lines @@
 #endif
 }
 
 #ifdef SK_PRINT_CODEC_MESSAGES
     #define SkCodecPrintf SkDebugf
 #else
     #define SkCodecPrintf(...)
 #endif
 
 #endif // SkCodecPriv_DEFINED