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-rw-r--r--tools/SkBitmapRegionCanvas.cpp189
-rw-r--r--tools/SkBitmapRegionCanvas.h43
-rw-r--r--tools/SkBitmapRegionDecoderInterface.cpp51
-rw-r--r--tools/SkBitmapRegionDecoderInterface.h77
-rw-r--r--tools/SkBitmapRegionSampler.cpp50
-rw-r--r--tools/SkBitmapRegionSampler.h41
6 files changed, 451 insertions, 0 deletions
diff --git a/tools/SkBitmapRegionCanvas.cpp b/tools/SkBitmapRegionCanvas.cpp
new file mode 100644
index 0000000000..2344d9020f
--- /dev/null
+++ b/tools/SkBitmapRegionCanvas.cpp
@@ -0,0 +1,189 @@
+/*
+ * 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 "SkCanvas.h"
+#include "SkScanlineDecoder.h"
+
+SkBitmapRegionCanvas::SkBitmapRegionCanvas(SkScanlineDecoder* decoder)
+ : INHERITED(decoder->getInfo().width(), decoder->getInfo().height())
+ , fDecoder(decoder)
+{}
+
+/*
+ * Chooses the correct image subset offsets and dimensions for the partial decode.
+ */
+static inline void set_subset_region(int inputOffset, int inputDimension,
+ int imageOriginalDimension, int* imageSubsetOffset, int* outOffset,
+ int* imageSubsetDimension) {
+
+ // This must be at least zero, we can't start decoding the image at a negative coordinate.
+ *imageSubsetOffset = SkTMax(0, inputOffset);
+
+ // If inputOffset is less than zero, we decode to an offset location in the output bitmap.
+ *outOffset = *imageSubsetOffset - inputOffset;
+
+ // Use imageSusetOffset to make sure we don't decode pixels past the edge of the image.
+ // Use outOffset to make sure we don't decode pixels past the edge of the region.
+ *imageSubsetDimension = SkTMin(imageOriginalDimension - *imageSubsetOffset,
+ inputDimension - *outOffset);
+}
+
+/*
+ * Returns a scaled dimension based on the original dimension and the sample size.
+ * TODO: Share this implementation with SkScaledCodec.
+ */
+static int get_scaled_dimension(int srcDimension, int sampleSize) {
+ if (sampleSize > srcDimension) {
+ return 1;
+ }
+ return srcDimension / sampleSize;
+}
+
+/*
+ * Three differences from the Android version:
+ * Returns a Skia bitmap instead of an Android bitmap.
+ * Android version attempts to reuse a recycled bitmap.
+ * Removed the options object and used parameters for color type and
+ * sample size.
+ */
+SkBitmap* SkBitmapRegionCanvas::decodeRegion(int inputX, int inputY,
+ int inputWidth, int inputHeight,
+ int sampleSize,
+ SkColorType dstColorType) {
+ // Reject color types not supported by this method
+ if (kIndex_8_SkColorType == dstColorType || kGray_8_SkColorType == dstColorType) {
+ SkDebugf("Error: Color type not supported.\n");
+ return nullptr;
+ }
+
+ // The client may not necessarily request a region that is fully within
+ // the image. We may need to do some calculation to determine what part
+ // of the image to decode.
+
+ // The left offset of the portion of the image we want, where zero
+ // indicates the left edge of the image.
+ int imageSubsetX;
+
+ // The size of the output bitmap is determined by the size of the
+ // requested region, not by the size of the intersection of the region
+ // and the image dimensions. If inputX is negative, we will need to
+ // place decoded pixels into the output bitmap starting at a left offset.
+ // If this is non-zero, imageSubsetX must be zero.
+ int outX;
+
+ // The width of the portion of the image that we will write to the output
+ // bitmap. If the region is not fully contained within the image, this
+ // will not be the same as inputWidth.
+ int imageSubsetWidth;
+ set_subset_region(inputX, inputWidth, this->width(), &imageSubsetX, &outX, &imageSubsetWidth);
+
+ // The top offset of the portion of the image we want, where zero
+ // indicates the top edge of the image.
+ int imageSubsetY;
+
+ // The size of the output bitmap is determined by the size of the
+ // requested region, not by the size of the intersection of the region
+ // and the image dimensions. If inputY is negative, we will need to
+ // place decoded pixels into the output bitmap starting at a top offset.
+ // If this is non-zero, imageSubsetY must be zero.
+ int outY;
+
+ // The height of the portion of the image that we will write to the output
+ // bitmap. If the region is not fully contained within the image, this
+ // will not be the same as inputHeight.
+ int imageSubsetHeight;
+ set_subset_region(inputY, inputHeight, this->height(), &imageSubsetY, &outY,
+ &imageSubsetHeight);
+
+ if (imageSubsetWidth <= 0 || imageSubsetHeight <= 0) {
+ SkDebugf("Error: Region must intersect part of the image.\n");
+ return nullptr;
+ }
+
+ // Create the image info for the decode
+ SkAlphaType dstAlphaType = fDecoder->getInfo().alphaType();
+ if (kUnpremul_SkAlphaType == dstAlphaType) {
+ dstAlphaType = kPremul_SkAlphaType;
+ }
+ SkImageInfo decodeInfo = SkImageInfo::Make(this->width(), this->height(),
+ dstColorType, dstAlphaType);
+
+ // Start the scanline decoder
+ SkCodec::Result r = fDecoder->start(decodeInfo);
+ if (SkCodec::kSuccess != r) {
+ SkDebugf("Error: Could not start scanline decoder.\n");
+ return nullptr;
+ }
+
+ // Allocate a bitmap for the unscaled decode
+ SkBitmap tmp;
+ SkImageInfo tmpInfo = decodeInfo.makeWH(this->width(), imageSubsetHeight);
+ if (!tmp.tryAllocPixels(tmpInfo)) {
+ SkDebugf("Error: Could not allocate pixels.\n");
+ return nullptr;
+ }
+
+ // Skip the unneeded rows
+ if (SkCodec::kSuccess != fDecoder->skipScanlines(imageSubsetY)) {
+ SkDebugf("Error: Failed to skip scanlines.\n");
+ return nullptr;
+ }
+
+ // Decode the necessary rows
+ SkCodec::Result result = fDecoder->getScanlines(tmp.getAddr(0, 0), imageSubsetHeight,
+ tmp.rowBytes());
+ switch (result) {
+ case SkCodec::kSuccess:
+ case SkCodec::kIncompleteInput:
+ break;
+ default:
+ SkDebugf("Error: Failed to get scanlines.\n");
+ return nullptr;
+ }
+
+ // Calculate the size of the output
+ const int outWidth = get_scaled_dimension(inputWidth, sampleSize);
+ const int outHeight = get_scaled_dimension(inputHeight, sampleSize);
+
+ // Initialize the destination bitmap
+ SkAutoTDelete<SkBitmap> bitmap(new SkBitmap());
+ SkImageInfo dstInfo = decodeInfo.makeWH(outWidth, outHeight);
+ if (!bitmap->tryAllocPixels(dstInfo)) {
+ SkDebugf("Error: Could not allocate pixels.\n");
+ return nullptr;
+ }
+
+ // 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?
+ // TODO (msarett): This could be skipped if memory is zero initialized.
+ // This would matter if this code is moved to Android and
+ // uses Android bitmaps.
+ if (0 != outX || 0 != outY ||
+ inputX + inputWidth > this->width() ||
+ inputY + inputHeight > this->height()) {
+ 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) imageSubsetX, (SkScalar) 0,
+ (SkScalar) imageSubsetWidth, (SkScalar) imageSubsetHeight);
+ SkRect dst = SkRect::MakeXYWH((SkScalar) (outX / sampleSize), (SkScalar) (outY / sampleSize),
+ (SkScalar) get_scaled_dimension(imageSubsetWidth, sampleSize),
+ (SkScalar) get_scaled_dimension(imageSubsetHeight, 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 bitmap.detach();
+}
diff --git a/tools/SkBitmapRegionCanvas.h b/tools/SkBitmapRegionCanvas.h
new file mode 100644
index 0000000000..96631d70d3
--- /dev/null
+++ b/tools/SkBitmapRegionCanvas.h
@@ -0,0 +1,43 @@
+/*
+ * 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 "SkBitmap.h"
+#include "SkBitmapRegionDecoderInterface.h"
+#include "SkScanlineDecoder.h"
+
+/*
+ * This class implements SkBitmapRegionDecoder using an SkScanlineDecoder and
+ * an SkCanvas. It uses the scanline decoder to subset the height. It then
+ * will subset the width and scale by drawing to an SkCanvas.
+ */
+// FIXME (msarett): This implementation does not support WEBP, because WEBP
+// does not have a scanline decoder.
+class SkBitmapRegionCanvas : public SkBitmapRegionDecoderInterface {
+public:
+
+ /*
+ * Takes ownership of pointer to decoder
+ */
+ SkBitmapRegionCanvas(SkScanlineDecoder* decoder);
+
+ /*
+ * Three differences from the Android version:
+ * Returns a Skia bitmap instead of an Android bitmap.
+ * Android version attempts to reuse a recycled bitmap.
+ * Removed the options object and used parameters for color type and
+ * sample size.
+ */
+ SkBitmap* decodeRegion(int start_x, int start_y, int width, int height,
+ int sampleSize, SkColorType prefColorType) override;
+
+private:
+
+ SkAutoTDelete<SkScanlineDecoder> fDecoder;
+
+ typedef SkBitmapRegionDecoderInterface INHERITED;
+
+};
diff --git a/tools/SkBitmapRegionDecoderInterface.cpp b/tools/SkBitmapRegionDecoderInterface.cpp
new file mode 100644
index 0000000000..090f042ce3
--- /dev/null
+++ b/tools/SkBitmapRegionDecoderInterface.cpp
@@ -0,0 +1,51 @@
+/*
+ * 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 "SkBitmapRegionDecoderInterface.h"
+#include "SkBitmapRegionSampler.h"
+#include "SkScanlineDecoder.h"
+#include "SkImageDecoder.h"
+
+SkBitmapRegionDecoderInterface* SkBitmapRegionDecoderInterface::CreateBitmapRegionDecoder(
+ SkStreamRewindable* stream, Strategy strategy) {
+ switch (strategy) {
+ case kOriginal_Strategy: {
+ SkImageDecoder* decoder = SkImageDecoder::Factory(stream);
+ int width, height;
+ if (nullptr == decoder) {
+ SkDebugf("Error: Could not create image decoder.\n");
+ return nullptr;
+ }
+ if (!decoder->buildTileIndex(stream, &width, &height)) {
+ SkDebugf("Error: Could not build tile index.\n");
+ delete decoder;
+ return nullptr;
+ }
+ return new SkBitmapRegionSampler(decoder, width, height);
+ }
+ case kCanvas_Strategy: {
+ SkScanlineDecoder* decoder = SkScanlineDecoder::NewFromStream(stream);
+ if (nullptr == decoder) {
+ SkDebugf("Error: Failed to create decoder.\n");
+ return nullptr;
+ }
+ switch (decoder->getScanlineOrder()) {
+ case SkScanlineDecoder::kTopDown_SkScanlineOrder:
+ case SkScanlineDecoder::kNone_SkScanlineOrder:
+ break;
+ default:
+ SkDebugf("Error: Scanline ordering not supported.\n");
+ return nullptr;
+ }
+ return new SkBitmapRegionCanvas(decoder);
+ }
+ default:
+ SkASSERT(false);
+ return nullptr;
+ }
+}
diff --git a/tools/SkBitmapRegionDecoderInterface.h b/tools/SkBitmapRegionDecoderInterface.h
new file mode 100644
index 0000000000..bc28c2b2af
--- /dev/null
+++ b/tools/SkBitmapRegionDecoderInterface.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBitmapRegionDecoder_DEFINED
+#define SkBitmapRegionDecoder_DEFINED
+
+#include "SkBitmap.h"
+#include "SkStream.h"
+
+/*
+ * This class aims to provide an interface to test multiple implementations of
+ * SkBitmapRegionDecoder.
+ */
+class SkBitmapRegionDecoderInterface {
+public:
+
+ enum Strategy {
+ kCanvas_Strategy, // Draw to the canvas, uses SkCodec
+ kOriginal_Strategy, // Sampling, uses SkImageDecoder
+ // TODO (msarett): Add strategy for SkScaledCodec
+ };
+
+ /*
+ * @param stream Encoded image stream, takes ownership
+ * @param strategy Strategy used for scaling and subsetting
+ * @return Tries to create an SkBitmapRegionDecoder, returns NULL
+ * on failure
+ */
+ static SkBitmapRegionDecoderInterface* CreateBitmapRegionDecoder(
+ SkStreamRewindable* stream, Strategy strategy);
+
+ /*
+ * Decode a scaled region of the encoded image stream
+ *
+ * @param start_x X-coordinate of upper-left corner of region.
+ * This coordinate is unscaled, relative to the original dimensions.
+ * @param start_y Y-coordinate of upper-left corner of region.
+ * This coordinate is unscaled, relative to the original dimensions.
+ * @param width Width of the region to decode.
+ * This distance is unscaled, relative to the original dimensions.
+ * @param height Height of the region to decode.
+ * This distance is unscaled, relative to the original dimensions.
+ * @param sampleSize An integer downscaling factor for the decode.
+ * @param colorType Preferred output colorType.
+ * New implementations should return NULL if they do not support
+ * decoding to this color type.
+ * The old kOriginal_Strategy will decode to a default color type
+ * if this color type is unsupported.
+ * @return Pointer to a bitmap of the decoded region on success, NULL on
+ * failure.
+ */
+ virtual SkBitmap* decodeRegion(int start_x, int start_y, int width,
+ int height, int sampleSize,
+ SkColorType colorType) = 0;
+
+ int width() const { return fWidth; }
+ int height() const { return fHeight; }
+
+ virtual ~SkBitmapRegionDecoderInterface() {}
+
+protected:
+
+ SkBitmapRegionDecoderInterface(int width, int height)
+ : fWidth(width)
+ , fHeight(height)
+ {}
+
+private:
+ const int fWidth;
+ const int fHeight;
+};
+
+#endif
diff --git a/tools/SkBitmapRegionSampler.cpp b/tools/SkBitmapRegionSampler.cpp
new file mode 100644
index 0000000000..98c183daac
--- /dev/null
+++ b/tools/SkBitmapRegionSampler.cpp
@@ -0,0 +1,50 @@
+/*
+ * 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 "SkBitmapRegionSampler.h"
+
+SkBitmapRegionSampler::SkBitmapRegionSampler(SkImageDecoder* decoder, int width,
+ int height)
+ : INHERITED(width, height)
+ , fDecoder(decoder)
+{}
+
+/*
+ * Three differences from the Android version:
+ * Returns a Skia bitmap instead of an Android bitmap.
+ * Android version attempts to reuse a recycled bitmap.
+ * Removed the options object and used parameters for color type and
+ * sample size.
+ */
+SkBitmap* SkBitmapRegionSampler::decodeRegion(int start_x, int start_y,
+ int width, int height,
+ int sampleSize,
+ SkColorType prefColorType) {
+ // Match Android's default settings
+ fDecoder->setDitherImage(true);
+ fDecoder->setPreferQualityOverSpeed(false);
+ fDecoder->setRequireUnpremultipliedColors(false);
+ fDecoder->setSampleSize(sampleSize);
+
+ // kAlpha8 is the legacy representation of kGray8 used by SkImageDecoder
+ if (kGray_8_SkColorType == prefColorType) {
+ prefColorType = kAlpha_8_SkColorType;
+ }
+
+ SkIRect region;
+ region.fLeft = start_x;
+ region.fTop = start_y;
+ region.fRight = start_x + width;
+ region.fBottom = start_y + height;
+
+ SkAutoTDelete<SkBitmap> bitmap(new SkBitmap());
+ if (!fDecoder->decodeSubset(bitmap.get(), region, prefColorType)) {
+ SkDebugf("Error: decodeRegion failed.\n");
+ return nullptr;
+ }
+ return bitmap.detach();
+}
diff --git a/tools/SkBitmapRegionSampler.h b/tools/SkBitmapRegionSampler.h
new file mode 100644
index 0000000000..d2f738d3b5
--- /dev/null
+++ b/tools/SkBitmapRegionSampler.h
@@ -0,0 +1,41 @@
+/*
+ * 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 "SkBitmap.h"
+#include "SkBitmapRegionDecoderInterface.h"
+#include "SkImageDecoder.h"
+#include "SkTemplates.h"
+
+/*
+ * This class aims to duplicate the current implementation of
+ * SkBitmapRegionDecoder in Android.
+ */
+class SkBitmapRegionSampler : public SkBitmapRegionDecoderInterface {
+public:
+
+ /*
+ * Takes ownership of pointer to decoder
+ */
+ SkBitmapRegionSampler(SkImageDecoder* decoder, int width, int height);
+
+ /*
+ * Three differences from the Android version:
+ * Returns a Skia bitmap instead of an Android bitmap.
+ * Android version attempts to reuse a recycled bitmap.
+ * Removed the options object and used parameters for color type and
+ * sample size.
+ */
+ SkBitmap* decodeRegion(int start_x, int start_y, int width, int height,
+ int sampleSize, SkColorType prefColorType) override;
+
+private:
+
+ SkAutoTDelete<SkImageDecoder> fDecoder;
+
+ typedef SkBitmapRegionDecoderInterface INHERITED;
+
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 10:31:24 +0000