1 files changed, 140 insertions, 0 deletions
diff --git a/src/android/SkBitmapRegionCanvas.cpp b/src/android/SkBitmapRegionCanvas.cpp
new file mode 100644
index 0000000000..bac5dc1ffc
--- /dev/null
+++ b/src/android/SkBitmapRegionCanvas.cpp
@@ -0,0 +1,140 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmapRegionCanvas.h"
+#include "SkBitmapRegionDecoderPriv.h"
+#include "SkCanvas.h"
+#include "SkCodecPriv.h"
+
+SkBitmapRegionCanvas::SkBitmapRegionCanvas(SkCodec* decoder)
+    : INHERITED(decoder->getInfo().width(), decoder->getInfo().height())
+    , fDecoder(decoder)
+{}
+
+bool SkBitmapRegionCanvas::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
+        const SkIRect& desiredSubset, int sampleSize, SkColorType dstColorType,
+        bool requireUnpremul) {
+    // Reject color types not supported by this method
+    if (kIndex_8_SkColorType == dstColorType || kGray_8_SkColorType == dstColorType) {
+        SkCodecPrintf("Error: Color type not supported.\n");
+        return false;
+    }
+
+    // Reject requests for unpremultiplied alpha
+    if (requireUnpremul) {
+        SkCodecPrintf("Error: Alpha type not supported.\n");
+        return false;
+    }
+    SkAlphaType dstAlphaType = fDecoder->getInfo().alphaType();
+    if (kUnpremul_SkAlphaType == dstAlphaType) {
+        dstAlphaType = kPremul_SkAlphaType;
+    }
+
+    // FIXME: Can we add checks and support kIndex8 or unpremultiplied alpha in special cases?
+
+    // Fix the input sampleSize if necessary.
+    if (sampleSize < 1) {
+        sampleSize = 1;
+    }
+
+    // The size of the output bitmap is determined by the size of the
+    // requested subset, not by the size of the intersection of the subset
+    // and the image dimensions.
+    // If inputX is negative, we will need to place decoded pixels into the
+    // output bitmap starting at a left offset.  Call this outX.
+    // If outX is non-zero, subsetX must be zero.
+    // If inputY is negative, we will need to place decoded pixels into the
+    // output bitmap starting at a top offset.  Call this outY.
+    // If outY is non-zero, subsetY must be zero.
+    int outX;
+    int outY;
+    SkIRect subset = desiredSubset;
+    SubsetType type = adjust_subset_rect(fDecoder->getInfo().dimensions(), &subset, &outX, &outY);
+    if (SubsetType::kOutside_SubsetType == type) {
+        return false;
+    }
+
+    // Create the image info for the decode
+    SkImageInfo decodeInfo = SkImageInfo::Make(this->width(), this->height(),
+            dstColorType, dstAlphaType);
+
+    // Start the scanline decoder
+    SkCodec::Result r = fDecoder->startScanlineDecode(decodeInfo);
+    if (SkCodec::kSuccess != r) {
+        SkCodecPrintf("Error: Could not start scanline decoder.\n");
+        return false;
+    }
+
+    // Allocate a bitmap for the unscaled decode
+    SkBitmap tmp;
+    SkImageInfo tmpInfo = decodeInfo.makeWH(this->width(), subset.height());
+    if (!tmp.tryAllocPixels(tmpInfo)) {
+        SkCodecPrintf("Error: Could not allocate pixels.\n");
+        return false;
+    }
+
+    // Skip the unneeded rows
+    if (!fDecoder->skipScanlines(subset.y())) {
+        SkCodecPrintf("Error: Failed to skip scanlines.\n");
+        return false;
+    }
+
+    // Decode the necessary rows
+    fDecoder->getScanlines(tmp.getAddr(0, 0), subset.height(), tmp.rowBytes());
+
+    // Calculate the size of the output
+    const int outWidth = get_scaled_dimension(desiredSubset.width(), sampleSize);
+    const int outHeight = get_scaled_dimension(desiredSubset.height(), sampleSize);
+
+    // Initialize the destination bitmap
+    SkImageInfo dstInfo = decodeInfo.makeWH(outWidth, outHeight);
+    bitmap->setInfo(dstInfo, dstInfo.minRowBytes());
+    if (!bitmap->tryAllocPixels(allocator, nullptr)) {
+        SkCodecPrintf("Error: Could not allocate pixels.\n");
+        return false;
+    }
+
+    // Zero the bitmap if the region is not completely within the image.
+    // TODO (msarett): Can we make this faster by implementing it to only
+    //                 zero parts of the image that we won't overwrite with
+    //                 pixels?
+    if (SubsetType::kPartiallyInside_SubsetType == type) {
+        SkCodec::ZeroInitialized zeroInit = allocator ? allocator->zeroInit() :
+                    SkCodec::kNo_ZeroInitialized;
+        if (SkCodec::kNo_ZeroInitialized == zeroInit) {
+            bitmap->eraseColor(0);
+        }
+    }
+
+    // Use a canvas to crop and scale to the destination bitmap
+    SkCanvas canvas(*bitmap);
+    // TODO (msarett): Maybe we can take advantage of the fact that SkRect uses floats?
+    SkRect src = SkRect::MakeXYWH((SkScalar) subset.x(), (SkScalar) 0,
+            (SkScalar) subset.width(), (SkScalar) subset.height());
+    SkRect dst = SkRect::MakeXYWH((SkScalar) (outX / sampleSize), (SkScalar) (outY / sampleSize),
+            (SkScalar) get_scaled_dimension(subset.width(), sampleSize),
+            (SkScalar) get_scaled_dimension(subset.height(), sampleSize));
+    SkPaint paint;
+    // Overwrite the dst with the src pixels
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    // TODO (msarett): Test multiple filter qualities.  kNone is the default.
+    canvas.drawBitmapRect(tmp, src, dst, &paint);
+
+    return true;
+}
+
+bool SkBitmapRegionCanvas::conversionSupported(SkColorType colorType) {
+    // SkCanvas does not draw to these color types.
+    if (kIndex_8_SkColorType == colorType || kGray_8_SkColorType == colorType) {
+        return false;
+    }
+
+    // FIXME: Call virtual function when it lands.
+    SkImageInfo info = SkImageInfo::Make(0, 0, colorType, fDecoder->getInfo().alphaType(),
+            fDecoder->getInfo().profileType());
+    return conversion_possible(info, fDecoder->getInfo());
+}