ARGB image encoder for checksums.

src/images/SkImageEncoder_argb.cpp

Index: src/images/SkImageEncoder_argb.cpp
===================================================================
--- src/images/SkImageEncoder_argb.cpp	(revision 0)
+++ src/images/SkImageEncoder_argb.cpp	(working copy)
@@ -0,0 +1,119 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkImageEncoder.h"
+#include "SkBitmap.h"
+#include "SkColorPriv.h"
+#include "SkStream.h"
+#include "SkTemplates.h"
+
+class SkARGBImageEncoder : public SkImageEncoder {
+protected:
+    virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality) SK_OVERRIDE;
+
+private:
+    typedef SkImageEncoder INHERITED;
+};
+
+typedef void (*ScanlineImporter)(const uint8_t* in, uint8_t* argb, int width,
+                                 const SkPMColor* SK_RESTRICT ctable);
+
+static void ARGB_8888_To_ARGB(const uint8_t* in, uint8_t* argb, int width, const SkPMColor*) {
+  const uint32_t* SK_RESTRICT src = (const uint32_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint32_t c = *src++;
+      argb[0] = SkGetPackedA32(c);
+      argb[1] = SkGetPackedR32(c);
+      argb[2] = SkGetPackedG32(c);
+      argb[3] = SkGetPackedB32(c);
+      argb += 4;
+  }
+}
+
+static void RGB_565_To_ARGB(const uint8_t* in, uint8_t* argb, int width, const SkPMColor*) {
+  const uint16_t* SK_RESTRICT src = (const uint16_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint16_t c = *src++;
+      argb[0] = 0xFF;
+      argb[1] = SkPacked16ToR32(c);
+      argb[2] = SkPacked16ToG32(c);
+      argb[3] = SkPacked16ToB32(c);
+      argb += 4;
+  }
+}
+
+static void ARGB_4444_To_ARGB(const uint8_t* in, uint8_t* argb, int width, const SkPMColor*) {
+  const SkPMColor16* SK_RESTRICT src = (const SkPMColor16*)in;
+  for (int i = 0; i < width; ++i) {
+      const SkPMColor16 c = *src++;
+      argb[0] = SkPacked4444ToA32(c);
+      argb[1] = SkPacked4444ToR32(c);
+      argb[2] = SkPacked4444ToG32(c);
+      argb[3] = SkPacked4444ToB32(c);
+      argb += 4;
+  }
+}
+
+static void Index8_To_ARGB(const uint8_t* in, uint8_t* argb, int width,
+                           const SkPMColor* SK_RESTRICT ctable) {
+  const uint8_t* SK_RESTRICT src = (const uint8_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint32_t c = ctable[*src++];
+      argb[0] = SkGetPackedA32(c);
+      argb[1] = SkGetPackedR32(c);
+      argb[2] = SkGetPackedG32(c);
+      argb[3] = SkGetPackedB32(c);
+      argb += 4;
+  }
+}
+
+static ScanlineImporter ChooseImporter(const SkBitmap::Config& config) {
+    switch (config) {
+        case SkBitmap::kARGB_8888_Config:
+            return ARGB_8888_To_ARGB;
+        case SkBitmap::kRGB_565_Config:
+            return RGB_565_To_ARGB;
+        case SkBitmap::kARGB_4444_Config:
+            return ARGB_4444_To_ARGB;
+        case SkBitmap::kIndex8_Config:
+            return Index8_To_ARGB;
+        default:
+            return NULL;
+    }
+}
+
+bool SkARGBImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bitmap, int) {
+    const SkBitmap::Config config = bitmap.getConfig();
+    const ScanlineImporter scanline_import = ChooseImporter(config);
+    if (NULL == scanline_import) {
+        return false;
+    }
+
+    SkAutoLockPixels alp(bitmap);
+    const uint8_t* src = (uint8_t*)bitmap.getPixels();
+    if (NULL == bitmap.getPixels()) {
+        return false;
+    }
+
+    SkAutoLockColors ctLocker;
+    const SkPMColor* colors = ctLocker.lockColors(bitmap);
+
+    const int argbStride = bitmap.width() * 4;
+    SkAutoTDeleteArray<uint8_t> ada(new uint8_t[argbStride]);
+    uint8_t* argb = ada.get();
+    for (int y = 0; y < bitmap.height(); ++y) {
+        scanline_import(src + y * bitmap.rowBytes(), argb, bitmap.width(), colors);
+        stream->write(argb, argbStride);
+    }
+
+    return true;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+DEFINE_ENCODER_CREATOR(ARGBImageEncoder);
+///////////////////////////////////////////////////////////////////////////////