Add SkBitmap::readPixels() and reimplement copyTo and SkCanvas::readPixels

src/core/SkBitmapDevice.cpp

Index: src/core/SkBitmapDevice.cpp
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 86c5702f03845400a38fac4c6dd977fcbc8b136b..09b3b605f85a3e4b36a28e77d88a75135abfae3b 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -141,59 +141,8 @@ void* SkBitmapDevice::onAccessPixels(SkImageInfo* info, size_t* rowBytes) {
     return NULL;
 }
 
-static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB, size_t bytesPerRow,
-                        int rowCount) {
-    SkASSERT(bytesPerRow <= srcRB);
-    SkASSERT(bytesPerRow <= dstRB);
-    for (int i = 0; i < rowCount; ++i) {
-        memcpy(dst, src, bytesPerRow);
-        dst = (char*)dst + dstRB;
-        src = (const char*)src + srcRB;
-    }
-}
-
 #include "SkConfig8888.h"
 
-static bool copy_pixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
-                        const SkImageInfo& srcInfo, const void* srcPixels, size_t srcRowBytes) {
-    if (srcInfo.dimensions() != dstInfo.dimensions()) {
-        return false;
-    }
-    if (4 == srcInfo.bytesPerPixel() && 4 == dstInfo.bytesPerPixel()) {
-        SkDstPixelInfo dstPI;
-        dstPI.fColorType = dstInfo.colorType();
-        dstPI.fAlphaType = dstInfo.alphaType();
-        dstPI.fPixels = dstPixels;
-        dstPI.fRowBytes = dstRowBytes;
-
-        SkSrcPixelInfo srcPI;
-        srcPI.fColorType = srcInfo.colorType();
-        srcPI.fAlphaType = srcInfo.alphaType();
-        srcPI.fPixels = srcPixels;
-        srcPI.fRowBytes = srcRowBytes;
-
-        return srcPI.convertPixelsTo(&dstPI, srcInfo.width(), srcInfo.height());
-    }
-    if (srcInfo.colorType() == dstInfo.colorType()) {
-        switch (srcInfo.colorType()) {
-            case kRGB_565_SkColorType:
-            case kAlpha_8_SkColorType:
-                break;
-            case kARGB_4444_SkColorType:
-                if (srcInfo.alphaType() != dstInfo.alphaType()) {
-                    return false;
-                }
-                break;
-            default:
-                return false;
-        }
-        rect_memcpy(dstPixels, dstRowBytes, srcPixels, srcRowBytes,
-                    srcInfo.width() * srcInfo.bytesPerPixel(), srcInfo.height());
-    }
-    // TODO: add support for more conversions as needed
-    return false;
-}
-
 bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPixels,
                                    size_t srcRowBytes, int x, int y) {
     // since we don't stop creating un-pixeled devices yet, check for no pixels here
@@ -208,7 +157,7 @@ bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPi
     void* dstPixels = fBitmap.getAddr(x, y);
     size_t dstRowBytes = fBitmap.rowBytes();
 
-    if (copy_pixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
+    if (SkPixelInfo::CopyPixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
         fBitmap.notifyPixelsChanged();
         return true;
     }
@@ -217,28 +166,7 @@ bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPi
 
 bool SkBitmapDevice::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                                   int x, int y) {
-    // since we don't stop creating un-pixeled devices yet, check for no pixels here
-    if (NULL == fBitmap.getPixels()) {
-        return false;
-    }
-
-    SkImageInfo srcInfo = fBitmap.info();
-
-    // perhaps can relax these in the future
-    if (4 != dstInfo.bytesPerPixel()) {
-        return false;
-    }
-    if (4 != srcInfo.bytesPerPixel()) {
-        return false;
-    }
-
-    srcInfo.fWidth = dstInfo.width();
-    srcInfo.fHeight = dstInfo.height();
-
-    const void* srcPixels = fBitmap.getAddr(x, y);
-    const size_t srcRowBytes = fBitmap.rowBytes();
-
-    return copy_pixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes);
+    return fBitmap.readPixels(dstInfo, dstPixels, dstRowBytes, x, y);
 }
 
 ///////////////////////////////////////////////////////////////////////////////