Revert of 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 09b3b605f85a3e4b36a28e77d88a75135abfae3b..86c5702f03845400a38fac4c6dd977fcbc8b136b 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -141,7 +141,58 @@
     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) {
@@ -157,7 +208,7 @@
     void* dstPixels = fBitmap.getAddr(x, y);
     size_t dstRowBytes = fBitmap.rowBytes();
 
-    if (SkPixelInfo::CopyPixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
+    if (copy_pixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
         fBitmap.notifyPixelsChanged();
         return true;
     }
@@ -166,7 +217,28 @@
 
 bool SkBitmapDevice::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                                   int x, int y) {
-    return fBitmap.readPixels(dstInfo, dstPixels, dstRowBytes, x, 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);
 }
 
 ///////////////////////////////////////////////////////////////////////////////