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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /image/DownscalingFilter.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'image/DownscalingFilter.h')
-rw-r--r-- | image/DownscalingFilter.h | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/image/DownscalingFilter.h b/image/DownscalingFilter.h new file mode 100644 index 000000000..6b0d3b26b --- /dev/null +++ b/image/DownscalingFilter.h @@ -0,0 +1,380 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/** + * DownscalingSurfaceFilter is a SurfaceFilter implementation for use with + * SurfacePipe which performs Lanczos downscaling. + * + * It's in this header file, separated from the other SurfaceFilters, because + * some preprocessor magic is necessary to ensure that there aren't compilation + * issues on platforms where Skia is unavailable. + */ + +#ifndef mozilla_image_DownscalingFilter_h +#define mozilla_image_DownscalingFilter_h + +#include <algorithm> +#include <ctime> +#include <stdint.h> + +#include "mozilla/Maybe.h" +#include "mozilla/SSE.h" +#include "mozilla/mips.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/gfx/2D.h" +#include "gfxPrefs.h" + +#ifdef MOZ_ENABLE_SKIA +#include "convolver.h" +#include "image_operations.h" +#include "skia/include/core/SkTypes.h" +#endif + +#include "SurfacePipe.h" + +namespace mozilla { +namespace image { + +////////////////////////////////////////////////////////////////////////////// +// DownscalingFilter +////////////////////////////////////////////////////////////////////////////// + +template <typename Next> class DownscalingFilter; + +/** + * A configuration struct for DownscalingConfig. + */ +struct DownscalingConfig +{ + template <typename Next> using Filter = DownscalingFilter<Next>; + gfx::IntSize mInputSize; /// The size of the input image. We'll downscale + /// from this size to the input size of the next + /// SurfaceFilter in the chain. + gfx::SurfaceFormat mFormat; /// The pixel format - BGRA or BGRX. (BGRX has + /// slightly better performance.) +}; + +#ifndef MOZ_ENABLE_SKIA + +/** + * DownscalingFilter requires Skia. This is a fallback implementation for + * non-Skia builds that fails when Configure() is called (which will prevent + * SurfacePipeFactory from returning an instance of it) and crashes if a caller + * manually constructs an instance and attempts to actually use it. Callers + * should avoid this by ensuring that they do not request downscaling in + * non-Skia builds. + */ +template <typename Next> +class DownscalingFilter final : public SurfaceFilter +{ +public: + Maybe<SurfaceInvalidRect> TakeInvalidRect() override { return Nothing(); } + + template <typename... Rest> + nsresult Configure(const DownscalingConfig& aConfig, Rest... aRest) + { + return NS_ERROR_FAILURE; + } + +protected: + uint8_t* DoResetToFirstRow() override { MOZ_CRASH(); return nullptr; } + uint8_t* DoAdvanceRow() override { MOZ_CRASH(); return nullptr; } +}; + +#else + +/** + * DownscalingFilter performs Lanczos downscaling, taking image input data at one size + * and outputting it rescaled to a different size. + * + * The 'Next' template parameter specifies the next filter in the chain. + */ +template <typename Next> +class DownscalingFilter final : public SurfaceFilter +{ +public: + DownscalingFilter() + : mXFilter(MakeUnique<skia::ConvolutionFilter1D>()) + , mYFilter(MakeUnique<skia::ConvolutionFilter1D>()) + , mWindowCapacity(0) + , mRowsInWindow(0) + , mInputRow(0) + , mOutputRow(0) + , mHasAlpha(true) + { + MOZ_ASSERT(gfxPrefs::ImageDownscaleDuringDecodeEnabled(), + "Downscaling even though downscale-during-decode is disabled?"); + } + + ~DownscalingFilter() + { + ReleaseWindow(); + } + + template <typename... Rest> + nsresult Configure(const DownscalingConfig& aConfig, Rest... aRest) + { + nsresult rv = mNext.Configure(aRest...); + if (NS_FAILED(rv)) { + return rv; + } + + if (mNext.IsValidPalettedPipe()) { + NS_WARNING("Created a downscaler for a paletted surface?"); + return NS_ERROR_INVALID_ARG; + } + if (mNext.InputSize() == aConfig.mInputSize) { + NS_WARNING("Created a downscaler, but not downscaling?"); + return NS_ERROR_INVALID_ARG; + } + if (mNext.InputSize().width > aConfig.mInputSize.width) { + NS_WARNING("Created a downscaler, but width is larger"); + return NS_ERROR_INVALID_ARG; + } + if (mNext.InputSize().height > aConfig.mInputSize.height) { + NS_WARNING("Created a downscaler, but height is larger"); + return NS_ERROR_INVALID_ARG; + } + if (aConfig.mInputSize.width <= 0 || aConfig.mInputSize.height <= 0) { + NS_WARNING("Invalid input size for DownscalingFilter"); + return NS_ERROR_INVALID_ARG; + } + + mInputSize = aConfig.mInputSize; + gfx::IntSize outputSize = mNext.InputSize(); + mScale = gfxSize(double(mInputSize.width) / outputSize.width, + double(mInputSize.height) / outputSize.height); + mHasAlpha = aConfig.mFormat == gfx::SurfaceFormat::B8G8R8A8; + + ReleaseWindow(); + + auto resizeMethod = skia::ImageOperations::RESIZE_LANCZOS3; + + skia::resize::ComputeFilters(resizeMethod, + mInputSize.width, outputSize.width, + 0, outputSize.width, + mXFilter.get()); + + skia::resize::ComputeFilters(resizeMethod, + mInputSize.height, outputSize.height, + 0, outputSize.height, + mYFilter.get()); + + // Allocate the buffer, which contains scanlines of the input image. + mRowBuffer.reset(new (fallible) + uint8_t[PaddedWidthInBytes(mInputSize.width)]); + if (MOZ_UNLIKELY(!mRowBuffer)) { + return NS_ERROR_OUT_OF_MEMORY; + } + + // Clear the buffer to avoid writing uninitialized memory to the output. + memset(mRowBuffer.get(), 0, PaddedWidthInBytes(mInputSize.width)); + + // Allocate the window, which contains horizontally downscaled scanlines. (We + // can store scanlines which are already downscaled because our downscaling + // filter is separable.) + mWindowCapacity = mYFilter->max_filter(); + mWindow.reset(new (fallible) uint8_t*[mWindowCapacity]); + if (MOZ_UNLIKELY(!mWindow)) { + return NS_ERROR_OUT_OF_MEMORY; + } + + // Allocate the "window" of recent rows that we keep in memory as input for + // the downscaling code. We intentionally iterate through the entire array + // even if an allocation fails, to ensure that all the pointers in it are + // either valid or nullptr. That in turn ensures that ReleaseWindow() can + // clean up correctly. + bool anyAllocationFailed = false; + const uint32_t windowRowSizeInBytes = PaddedWidthInBytes(outputSize.width); + for (int32_t i = 0; i < mWindowCapacity; ++i) { + mWindow[i] = new (fallible) uint8_t[windowRowSizeInBytes]; + anyAllocationFailed = anyAllocationFailed || mWindow[i] == nullptr; + } + + if (MOZ_UNLIKELY(anyAllocationFailed)) { + return NS_ERROR_OUT_OF_MEMORY; + } + + ConfigureFilter(mInputSize, sizeof(uint32_t)); + return NS_OK; + } + + Maybe<SurfaceInvalidRect> TakeInvalidRect() override + { + Maybe<SurfaceInvalidRect> invalidRect = mNext.TakeInvalidRect(); + + if (invalidRect) { + // Compute the input space invalid rect by scaling. + invalidRect->mInputSpaceRect.ScaleRoundOut(mScale.width, mScale.height); + } + + return invalidRect; + } + +protected: + uint8_t* DoResetToFirstRow() override + { + mNext.ResetToFirstRow(); + + mInputRow = 0; + mOutputRow = 0; + mRowsInWindow = 0; + + return GetRowPointer(); + } + + uint8_t* DoAdvanceRow() override + { + if (mInputRow >= mInputSize.height) { + NS_WARNING("Advancing DownscalingFilter past the end of the input"); + return nullptr; + } + + if (mOutputRow >= mNext.InputSize().height) { + NS_WARNING("Advancing DownscalingFilter past the end of the output"); + return nullptr; + } + + int32_t filterOffset = 0; + int32_t filterLength = 0; + GetFilterOffsetAndLength(mYFilter, mOutputRow, + &filterOffset, &filterLength); + + int32_t inputRowToRead = filterOffset + mRowsInWindow; + MOZ_ASSERT(mInputRow <= inputRowToRead, "Reading past end of input"); + if (mInputRow == inputRowToRead) { + skia::ConvolveHorizontally(mRowBuffer.get(), *mXFilter, + mWindow[mRowsInWindow++], mHasAlpha, + supports_sse2() || supports_mmi()); + } + + MOZ_ASSERT(mOutputRow < mNext.InputSize().height, + "Writing past end of output"); + + while (mRowsInWindow == filterLength) { + DownscaleInputRow(); + + if (mOutputRow == mNext.InputSize().height) { + break; // We're done. + } + + GetFilterOffsetAndLength(mYFilter, mOutputRow, + &filterOffset, &filterLength); + } + + mInputRow++; + + return mInputRow < mInputSize.height ? GetRowPointer() + : nullptr; + } + +private: + uint8_t* GetRowPointer() const { return mRowBuffer.get(); } + + static uint32_t PaddedWidthInBytes(uint32_t aLogicalWidth) + { + // Convert from width in BGRA/BGRX pixels to width in bytes, padding by 15 + // to handle overreads by the SIMD code inside Skia. + return aLogicalWidth * sizeof(uint32_t) + 15; + } + + static void + GetFilterOffsetAndLength(UniquePtr<skia::ConvolutionFilter1D>& aFilter, + int32_t aOutputImagePosition, + int32_t* aFilterOffsetOut, + int32_t* aFilterLengthOut) + { + MOZ_ASSERT(aOutputImagePosition < aFilter->num_values()); + aFilter->FilterForValue(aOutputImagePosition, + aFilterOffsetOut, + aFilterLengthOut); + } + + void DownscaleInputRow() + { + typedef skia::ConvolutionFilter1D::Fixed FilterValue; + + MOZ_ASSERT(mOutputRow < mNext.InputSize().height, + "Writing past end of output"); + + int32_t filterOffset = 0; + int32_t filterLength = 0; + MOZ_ASSERT(mOutputRow < mYFilter->num_values()); + auto filterValues = + mYFilter->FilterForValue(mOutputRow, &filterOffset, &filterLength); + + mNext.template WriteUnsafeComputedRow<uint32_t>([&](uint32_t* aRow, + uint32_t aLength) { + skia::ConvolveVertically(static_cast<const FilterValue*>(filterValues), + filterLength, mWindow.get(), mXFilter->num_values(), + reinterpret_cast<uint8_t*>(aRow), mHasAlpha, + supports_sse2() || supports_mmi()); + }); + + mOutputRow++; + + if (mOutputRow == mNext.InputSize().height) { + return; // We're done. + } + + int32_t newFilterOffset = 0; + int32_t newFilterLength = 0; + GetFilterOffsetAndLength(mYFilter, mOutputRow, + &newFilterOffset, &newFilterLength); + + int diff = newFilterOffset - filterOffset; + MOZ_ASSERT(diff >= 0, "Moving backwards in the filter?"); + + // Shift the buffer. We're just moving pointers here, so this is cheap. + mRowsInWindow -= diff; + mRowsInWindow = std::max(mRowsInWindow, 0); + for (int32_t i = 0; i < mRowsInWindow; ++i) { + std::swap(mWindow[i], mWindow[filterLength - mRowsInWindow + i]); + } + } + + void ReleaseWindow() + { + if (!mWindow) { + return; + } + + for (int32_t i = 0; i < mWindowCapacity; ++i) { + delete[] mWindow[i]; + } + + mWindow = nullptr; + mWindowCapacity = 0; + } + + Next mNext; /// The next SurfaceFilter in the chain. + + gfx::IntSize mInputSize; /// The size of the input image. + gfxSize mScale; /// The scale factors in each dimension. + /// Computed from @mInputSize and + /// the next filter's input size. + + UniquePtr<uint8_t[]> mRowBuffer; /// The buffer into which input is written. + UniquePtr<uint8_t*[]> mWindow; /// The last few rows which were written. + + UniquePtr<skia::ConvolutionFilter1D> mXFilter; /// The Lanczos filter in X. + UniquePtr<skia::ConvolutionFilter1D> mYFilter; /// The Lanczos filter in Y. + + int32_t mWindowCapacity; /// How many rows the window contains. + + int32_t mRowsInWindow; /// How many rows we've buffered in the window. + int32_t mInputRow; /// The current row we're reading. (0-indexed) + int32_t mOutputRow; /// The current row we're writing. (0-indexed) + + bool mHasAlpha; /// If true, the image has transparency. +}; + +#endif + +} // namespace image +} // namespace mozilla + +#endif // mozilla_image_DownscalingFilter_h |