/* -*- 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/. */
/**
* A SurfacePipe is a pipeline that consists of a series of SurfaceFilters
* terminating in a SurfaceSink. Each SurfaceFilter transforms the image data in
* some way before the SurfaceSink ultimately writes it to the surface. This
* design allows for each transformation to be tested independently, for the
* transformations to be combined as needed to meet the needs of different
* situations, and for all image decoders to share the same code for these
* transformations.
*
* Writing to the SurfacePipe is done using lambdas that act as generator
* functions. Because the SurfacePipe machinery controls where the writes take
* place, a bug in an image decoder cannot cause a buffer overflow of the
* underlying surface.
*/
#ifndef mozilla_image_SurfacePipe_h
#define mozilla_image_SurfacePipe_h
#include <stdint.h>
#include "nsDebug.h"
#include "mozilla/Likely.h"
#include "mozilla/Maybe.h"
#include "mozilla/Move.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/Unused.h"
#include "mozilla/Variant.h"
#include "mozilla/gfx/2D.h"
namespace mozilla {
namespace image {
class Decoder;
/**
* An invalid rect for a surface. Results are given both in the space of the
* input image (i.e., before any SurfaceFilters are applied) and in the space
* of the output surface (after all SurfaceFilters).
*/
struct SurfaceInvalidRect {
gfx::IntRect mInputSpaceRect; /// The invalid rect in pre-SurfacePipe space.
gfx::IntRect
mOutputSpaceRect; /// The invalid rect in post-SurfacePipe space.
};
/**
* An enum used to allow the lambdas passed to WritePixels() to communicate
* their state to the caller.
*/
enum class WriteState : uint8_t {
NEED_MORE_DATA, /// The lambda ran out of data.
FINISHED, /// The lambda is done writing to the surface; future writes
/// will fail.
FAILURE /// The lambda encountered an error. The caller may recover
/// if possible and continue to write. (This never indicates
/// an error in the SurfacePipe machinery itself; it's only
/// generated by the lambdas.)
};
/**
* A template alias used to make the return value of WritePixels() lambdas
* (which may return either a pixel value or a WriteState) easier to specify.
*/
template <typename PixelType>
using NextPixel = Variant<PixelType, WriteState>;
/**
* SurfaceFilter is the abstract superclass of SurfacePipe pipeline stages. It
* implements the the code that actually writes to the surface - WritePixels()
* and the other Write*() methods - which are non-virtual for efficiency.
*
* SurfaceFilter's API is nonpublic; only SurfacePipe and other SurfaceFilters
* should use it. Non-SurfacePipe code should use the methods on SurfacePipe.
*
* To implement a SurfaceFilter, it's necessary to subclass SurfaceFilter and
* implement, at a minimum, the pure virtual methods. It's also necessary to
* define a Config struct with a Filter typedef member that identifies the
* matching SurfaceFilter class, and a Configure() template method. See an
* existing SurfaceFilter subclass, such as RemoveFrameRectFilter, for an
* example of how the Configure() method must be implemented. It takes a list of
* Config structs, passes the tail of the list to the next filter in the chain's
* Configure() method, and then uses the head of the list to configure itself. A
* SurfaceFilter's Configure() method must also call
* SurfaceFilter::ConfigureFilter() to provide the Write*() methods with the
* information they need to do their jobs.
*/
class SurfaceFilter {
public:
SurfaceFilter() : mRowPointer(nullptr), mCol(0), mPixelSize(0) {}
virtual ~SurfaceFilter() {}
/**
* Reset this surface to the first row. It's legal for this filter to throw
* away any previously written data at this point, as all rows must be written
* to on every pass.
*
* @return a pointer to the buffer for the first row.
*/
uint8_t* ResetToFirstRow() {
mCol = 0;
mRowPointer = DoResetToFirstRow();
return mRowPointer;
}
/**
* Called by WritePixels() to advance this filter to the next row.
*
* @return a pointer to the buffer for the next row, or nullptr to indicate
* that we've finished the entire surface.
*/
uint8_t* AdvanceRow() {
mCol = 0;
mRowPointer = DoAdvanceRow();
return mRowPointer;
}
/// @return a pointer to the buffer for the current row.
uint8_t* CurrentRowPointer() const { return mRowPointer; }
/// @return true if we've finished writing to the surface.
bool IsSurfaceFinished() const { return mRowPointer == nullptr; }
/// @return the input size this filter expects.
gfx::IntSize InputSize() const { return mInputSize; }
/**
* Write pixels to the surface one at a time by repeatedly calling a lambda
* that yields pixels. WritePixels() is completely memory safe.
*
* Writing continues until every pixel in the surface has been written to
* (i.e., IsSurfaceFinished() returns true) or the lambda returns a WriteState
* which WritePixels() will return to the caller.
*
* The template parameter PixelType must be uint8_t (for paletted surfaces) or
* uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
* size passed to ConfigureFilter().
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove the PixelType template parameter from this
* method.
*
* @param aFunc A lambda that functions as a generator, yielding the next
* pixel in the surface each time it's called. The lambda must
* return a NextPixel<PixelType> value.
*
* @return A WriteState value indicating the lambda generator's state.
* WritePixels() itself will return WriteState::FINISHED if writing
* has finished, regardless of the lambda's internal state.
*/
template <typename PixelType, typename Func>
WriteState WritePixels(Func aFunc) {
Maybe<WriteState> result;
while (!(result = DoWritePixelsToRow<PixelType>(Forward<Func>(aFunc)))) {
}
return *result;
}
/**
* A variant of WritePixels() that writes a single row of pixels to the
* surface one at a time by repeatedly calling a lambda that yields pixels.
* WritePixelsToRow() is completely memory safe.
*
* Writing continues until every pixel in the row has been written to. If the
* surface is complete at that pointer, WriteState::FINISHED is returned;
* otherwise, WritePixelsToRow() returns WriteState::NEED_MORE_DATA. The
* lambda can terminate writing early by returning a WriteState itself, which
* WritePixelsToRow() will return to the caller.
*
* The template parameter PixelType must be uint8_t (for paletted surfaces) or
* uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
* size passed to ConfigureFilter().
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove the PixelType template parameter from this
* method.
*
* @param aFunc A lambda that functions as a generator, yielding the next
* pixel in the surface each time it's called. The lambda must
* return a NextPixel<PixelType> value.
*
* @return A WriteState value indicating the lambda generator's state.
* WritePixels() itself will return WriteState::FINISHED if writing
* the entire surface has finished, or WriteState::NEED_MORE_DATA if
* writing the row has finished, regardless of the lambda's internal
* state.
*/
template <typename PixelType, typename Func>
WriteState WritePixelsToRow(Func aFunc) {
return DoWritePixelsToRow<PixelType>(Forward<Func>(aFunc))
.valueOr(WriteState::NEED_MORE_DATA);
}
/**
* Write a row to the surface by copying from a buffer. This is bounds checked
* and memory safe with respect to the surface, but care must still be taken
* by the caller not to overread the source buffer. This variant of
* WriteBuffer() requires a source buffer which contains |mInputSize.width|
* pixels.
*
* The template parameter PixelType must be uint8_t (for paletted surfaces) or
* uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
* size passed to ConfigureFilter().
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove the PixelType template parameter from this
* method.
*
* @param aSource A buffer to copy from. This buffer must be
* |mInputSize.width| pixels wide, which means
* |mInputSize.width * sizeof(PixelType)| bytes. May not be
* null.
*
* @return WriteState::FINISHED if the entire surface has been written to.
* Otherwise, returns WriteState::NEED_MORE_DATA. If a null |aSource|
* value is passed, returns WriteState::FAILURE.
*/
template <typename PixelType>
WriteState WriteBuffer(const PixelType* aSource) {
return WriteBuffer(aSource, 0, mInputSize.width);
}
/**
* Write a row to the surface by copying from a buffer. This is bounds checked
* and memory safe with respect to the surface, but care must still be taken
* by the caller not to overread the source buffer. This variant of
* WriteBuffer() reads at most @aLength pixels from the buffer and writes them
* to the row starting at @aStartColumn. Any pixels in columns before
* @aStartColumn or after the pixels copied from the buffer are cleared.
*
* Bounds checking failures produce warnings in debug builds because although
* the bounds checking maintains safety, this kind of failure could indicate a
* bug in the calling code.
*
* The template parameter PixelType must be uint8_t (for paletted surfaces) or
* uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
* size passed to ConfigureFilter().
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove the PixelType template parameter from this
* method.
*
* @param aSource A buffer to copy from. This buffer must be @aLength pixels
* wide, which means |aLength * sizeof(PixelType)| bytes. May
* not be null.
* @param aStartColumn The column to start writing to in the row. Columns
* before this are cleared.
* @param aLength The number of bytes, at most, which may be copied from
* @aSource. Fewer bytes may be copied in practice due to
* bounds checking.
*
* @return WriteState::FINISHED if the entire surface has been written to.
* Otherwise, returns WriteState::NEED_MORE_DATA. If a null |aSource|
* value is passed, returns WriteState::FAILURE.
*/
template <typename PixelType>
WriteState WriteBuffer(const PixelType* aSource, const size_t aStartColumn,
const size_t aLength) {
MOZ_ASSERT(mPixelSize == 1 || mPixelSize == 4);
MOZ_ASSERT_IF(mPixelSize == 1, sizeof(PixelType) == sizeof(uint8_t));
MOZ_ASSERT_IF(mPixelSize == 4, sizeof(PixelType) == sizeof(uint32_t));
if (IsSurfaceFinished()) {
return WriteState::FINISHED; // Already done.
}
if (MOZ_UNLIKELY(!aSource)) {
NS_WARNING("Passed a null pointer to WriteBuffer");
return WriteState::FAILURE;
}
PixelType* dest = reinterpret_cast<PixelType*>(mRowPointer);
// Clear the area before |aStartColumn|.
const size_t prefixLength =
std::min<size_t>(mInputSize.width, aStartColumn);
if (MOZ_UNLIKELY(prefixLength != aStartColumn)) {
NS_WARNING("Provided starting column is out-of-bounds in WriteBuffer");
}
memset(dest, 0, mInputSize.width * sizeof(PixelType));
dest += prefixLength;
// Write |aLength| pixels from |aSource| into the row, with bounds checking.
const size_t bufferLength =
std::min<size_t>(mInputSize.width - prefixLength, aLength);
if (MOZ_UNLIKELY(bufferLength != aLength)) {
NS_WARNING("Provided buffer length is out-of-bounds in WriteBuffer");
}
memcpy(dest, aSource, bufferLength * sizeof(PixelType));
dest += bufferLength;
// Clear the rest of the row.
const size_t suffixLength =
mInputSize.width - (prefixLength + bufferLength);
memset(dest, 0, suffixLength * sizeof(PixelType));
AdvanceRow();
return IsSurfaceFinished() ? WriteState::FINISHED
: WriteState::NEED_MORE_DATA;
}
/**
* Write an empty row to the surface. If some pixels have already been written
* to this row, they'll be discarded.
*
* @return WriteState::FINISHED if the entire surface has been written to.
* Otherwise, returns WriteState::NEED_MORE_DATA.
*/
WriteState WriteEmptyRow() {
if (IsSurfaceFinished()) {
return WriteState::FINISHED; // Already done.
}
memset(mRowPointer, 0, mInputSize.width * mPixelSize);
AdvanceRow();
return IsSurfaceFinished() ? WriteState::FINISHED
: WriteState::NEED_MORE_DATA;
}
/**
* Write a row to the surface by calling a lambda that uses a pointer to
* directly write to the row. This is unsafe because SurfaceFilter can't
* provide any bounds checking; that's up to the lambda itself. For this
* reason, the other Write*() methods should be preferred whenever it's
* possible to use them; WriteUnsafeComputedRow() should be used only when
* it's absolutely necessary to avoid extra copies or other performance
* penalties.
*
* This method should never be exposed to SurfacePipe consumers; it's strictly
* for use in SurfaceFilters. If external code needs this method, it should
* probably be turned into a SurfaceFilter.
*
* The template parameter PixelType must be uint8_t (for paletted surfaces) or
* uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
* size passed to ConfigureFilter().
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove the PixelType template parameter from this
* method.
*
* @param aFunc A lambda that writes directly to the row.
*
* @return WriteState::FINISHED if the entire surface has been written to.
* Otherwise, returns WriteState::NEED_MORE_DATA.
*/
template <typename PixelType, typename Func>
WriteState WriteUnsafeComputedRow(Func aFunc) {
MOZ_ASSERT(mPixelSize == 1 || mPixelSize == 4);
MOZ_ASSERT_IF(mPixelSize == 1, sizeof(PixelType) == sizeof(uint8_t));
MOZ_ASSERT_IF(mPixelSize == 4, sizeof(PixelType) == sizeof(uint32_t));
if (IsSurfaceFinished()) {
return WriteState::FINISHED; // Already done.
}
// Call the provided lambda with a pointer to the buffer for the current
// row. This is unsafe because we can't do any bounds checking; the lambda
// itself has to be responsible for that.
PixelType* rowPtr = reinterpret_cast<PixelType*>(mRowPointer);
aFunc(rowPtr, mInputSize.width);
AdvanceRow();
return IsSurfaceFinished() ? WriteState::FINISHED
: WriteState::NEED_MORE_DATA;
}
//////////////////////////////////////////////////////////////////////////////
// Methods Subclasses Should Override
//////////////////////////////////////////////////////////////////////////////
/// @return true if this SurfaceFilter can be used with paletted surfaces.
virtual bool IsValidPalettedPipe() const { return false; }
/**
* @return a SurfaceInvalidRect representing the region of the surface that
* has been written to since the last time TakeInvalidRect() was
* called, or Nothing() if the region is empty (i.e. nothing has been
* written).
*/
virtual Maybe<SurfaceInvalidRect> TakeInvalidRect() = 0;
protected:
/**
* Called by ResetToFirstRow() to actually perform the reset. It's legal to
* throw away any previously written data at this point, as all rows must be
* written to on every pass.
*/
virtual uint8_t* DoResetToFirstRow() = 0;
/**
* Called by AdvanceRow() to actually advance this filter to the next row.
*
* @return a pointer to the buffer for the next row, or nullptr to indicate
* that we've finished the entire surface.
*/
virtual uint8_t* DoAdvanceRow() = 0;
//////////////////////////////////////////////////////////////////////////////
// Methods For Internal Use By Subclasses
//////////////////////////////////////////////////////////////////////////////
/**
* Called by subclasses' Configure() methods to initialize the configuration
* of this filter. After the filter is configured, calls ResetToFirstRow().
*
* @param aInputSize The input size of this filter, in pixels. The previous
* filter in the chain will expect to write into rows
* |aInputSize.width| pixels wide.
* @param aPixelSize How large, in bytes, each pixel in the surface is. This
* should be either 1 for paletted images or 4 for BGRA/BGRX
* images.
*/
void ConfigureFilter(gfx::IntSize aInputSize, uint8_t aPixelSize) {
mInputSize = aInputSize;
mPixelSize = aPixelSize;
ResetToFirstRow();
}
private:
/**
* An internal method used to implement both WritePixels() and
* WritePixelsToRow(). Those methods differ only in their behavior after a row
* is successfully written - WritePixels() continues to write another row,
* while WritePixelsToRow() returns to the caller. This method writes a single
* row and returns Some() if we either finished the entire surface or the
* lambda returned a WriteState indicating that we should return to the
* caller. If the row was successfully written without either of those things
* happening, it returns Nothing(), allowing WritePixels() and
* WritePixelsToRow() to implement their respective behaviors.
*/
template <typename PixelType, typename Func>
Maybe<WriteState> DoWritePixelsToRow(Func aFunc) {
MOZ_ASSERT(mPixelSize == 1 || mPixelSize == 4);
MOZ_ASSERT_IF(mPixelSize == 1, sizeof(PixelType) == sizeof(uint8_t));
MOZ_ASSERT_IF(mPixelSize == 4, sizeof(PixelType) == sizeof(uint32_t));
if (IsSurfaceFinished()) {
return Some(WriteState::FINISHED); // We're already done.
}
PixelType* rowPtr = reinterpret_cast<PixelType*>(mRowPointer);
for (; mCol < mInputSize.width; ++mCol) {
NextPixel<PixelType> result = aFunc();
if (result.template is<PixelType>()) {
rowPtr[mCol] = result.template as<PixelType>();
continue;
}
switch (result.template as<WriteState>()) {
case WriteState::NEED_MORE_DATA:
return Some(WriteState::NEED_MORE_DATA);
case WriteState::FINISHED:
ZeroOutRestOfSurface<PixelType>();
return Some(WriteState::FINISHED);
case WriteState::FAILURE:
// Note that we don't need to record this anywhere, because this
// indicates an error in aFunc, and there's nothing wrong with our
// machinery. The caller can recover as needed and continue writing to
// the row.
return Some(WriteState::FAILURE);
}
}
AdvanceRow(); // We've finished the row.
return IsSurfaceFinished() ? Some(WriteState::FINISHED) : Nothing();
}
template <typename PixelType>
void ZeroOutRestOfSurface() {
WritePixels<PixelType>([] { return AsVariant(PixelType(0)); });
}
gfx::IntSize mInputSize; /// The size of the input this filter expects.
uint8_t* mRowPointer; /// Pointer to the current row or null if finished.
int32_t mCol; /// The current column we're writing to. (0-indexed)
uint8_t mPixelSize; /// How large each pixel in the surface is, in bytes.
};
/**
* SurfacePipe is the public API that decoders should use to interact with a
* SurfaceFilter pipeline.
*/
class SurfacePipe {
public:
SurfacePipe() {}
SurfacePipe(SurfacePipe&& aOther) : mHead(Move(aOther.mHead)) {}
~SurfacePipe() {}
SurfacePipe& operator=(SurfacePipe&& aOther) {
MOZ_ASSERT(this != &aOther);
mHead = Move(aOther.mHead);
return *this;
}
/// Begins a new pass, seeking to the first row of the surface.
void ResetToFirstRow() {
MOZ_ASSERT(mHead, "Use before configured!");
mHead->ResetToFirstRow();
}
/**
* Write pixels to the surface one at a time by repeatedly calling a lambda
* that yields pixels. WritePixels() is completely memory safe.
*
* @see SurfaceFilter::WritePixels() for the canonical documentation.
*/
template <typename PixelType, typename Func>
WriteState WritePixels(Func aFunc) {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->WritePixels<PixelType>(Forward<Func>(aFunc));
}
/**
* A variant of WritePixels() that writes a single row of pixels to the
* surface one at a time by repeatedly calling a lambda that yields pixels.
* WritePixelsToRow() is completely memory safe.
*
* @see SurfaceFilter::WritePixelsToRow() for the canonical documentation.
*/
template <typename PixelType, typename Func>
WriteState WritePixelsToRow(Func aFunc) {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->WritePixelsToRow<PixelType>(Forward<Func>(aFunc));
}
/**
* Write a row to the surface by copying from a buffer. This is bounds checked
* and memory safe with respect to the surface, but care must still be taken
* by the caller not to overread the source buffer. This variant of
* WriteBuffer() requires a source buffer which contains |mInputSize.width|
* pixels.
*
* @see SurfaceFilter::WriteBuffer() for the canonical documentation.
*/
template <typename PixelType>
WriteState WriteBuffer(const PixelType* aSource) {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->WriteBuffer<PixelType>(aSource);
}
/**
* Write a row to the surface by copying from a buffer. This is bounds checked
* and memory safe with respect to the surface, but care must still be taken
* by the caller not to overread the source buffer. This variant of
* WriteBuffer() reads at most @aLength pixels from the buffer and writes them
* to the row starting at @aStartColumn. Any pixels in columns before
* @aStartColumn or after the pixels copied from the buffer are cleared.
*
* @see SurfaceFilter::WriteBuffer() for the canonical documentation.
*/
template <typename PixelType>
WriteState WriteBuffer(const PixelType* aSource, const size_t aStartColumn,
const size_t aLength) {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->WriteBuffer<PixelType>(aSource, aStartColumn, aLength);
}
/**
* Write an empty row to the surface. If some pixels have already been written
* to this row, they'll be discarded.
*
* @see SurfaceFilter::WriteEmptyRow() for the canonical documentation.
*/
WriteState WriteEmptyRow() {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->WriteEmptyRow();
}
/// @return true if we've finished writing to the surface.
bool IsSurfaceFinished() const { return mHead->IsSurfaceFinished(); }
/// @see SurfaceFilter::TakeInvalidRect() for the canonical documentation.
Maybe<SurfaceInvalidRect> TakeInvalidRect() const {
MOZ_ASSERT(mHead, "Use before configured!");
return mHead->TakeInvalidRect();
}
private:
friend class SurfacePipeFactory;
friend class TestSurfacePipeFactory;
explicit SurfacePipe(UniquePtr<SurfaceFilter>&& aHead) : mHead(Move(aHead)) {}
SurfacePipe(const SurfacePipe&) = delete;
SurfacePipe& operator=(const SurfacePipe&) = delete;
UniquePtr<SurfaceFilter> mHead; /// The first filter in the chain.
};
/**
* AbstractSurfaceSink contains shared implementation for both SurfaceSink and
* PalettedSurfaceSink.
*/
class AbstractSurfaceSink : public SurfaceFilter {
public:
AbstractSurfaceSink()
: mImageData(nullptr),
mImageDataLength(0),
mRow(0),
mFlipVertically(false) {}
Maybe<SurfaceInvalidRect> TakeInvalidRect() final;
protected:
uint8_t* DoResetToFirstRow() final;
uint8_t* DoAdvanceRow() final;
virtual uint8_t* GetRowPointer() const = 0;
gfx::IntRect
mInvalidRect; /// The region of the surface that has been written
/// to since the last call to TakeInvalidRect().
uint8_t* mImageData; /// A pointer to the beginning of the surface data.
uint32_t mImageDataLength; /// The length of the surface data.
uint32_t mRow; /// The row to which we're writing. (0-indexed)
bool mFlipVertically; /// If true, write the rows from top to bottom.
};
class SurfaceSink;
/// A configuration struct for SurfaceSink.
struct SurfaceConfig {
using Filter = SurfaceSink;
Decoder* mDecoder; /// Which Decoder to use to allocate the surface.
uint32_t mFrameNum; /// Which frame of animation this surface is for.
gfx::IntSize mOutputSize; /// The size of the surface.
gfx::SurfaceFormat mFormat; /// The surface format (BGRA or BGRX).
bool mFlipVertically; /// If true, write the rows from bottom to top.
};
/**
* A sink for normal (i.e., non-paletted) surfaces. It handles the allocation of
* the surface and protects against buffer overflow. This sink should be used
* for all non-animated images and for the first frame of animated images.
*
* Sinks must always be at the end of the SurfaceFilter chain.
*/
class SurfaceSink final : public AbstractSurfaceSink {
public:
nsresult Configure(const SurfaceConfig& aConfig);
protected:
uint8_t* GetRowPointer() const override;
};
class PalettedSurfaceSink;
struct PalettedSurfaceConfig {
using Filter = PalettedSurfaceSink;
Decoder* mDecoder; /// Which Decoder to use to allocate the surface.
uint32_t mFrameNum; /// Which frame of animation this surface is for.
gfx::IntSize mOutputSize; /// The logical size of the surface.
gfx::IntRect mFrameRect; /// The surface subrect which contains data.
gfx::SurfaceFormat mFormat; /// The surface format (BGRA or BGRX).
uint8_t mPaletteDepth; /// The palette depth of this surface.
bool mFlipVertically; /// If true, write the rows from bottom to top.
};
/**
* A sink for paletted surfaces. It handles the allocation of the surface and
* protects against buffer overflow. This sink can be used for frames of
* animated images except the first.
*
* Sinks must always be at the end of the SurfaceFilter chain.
*
* XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
* which means we can remove PalettedSurfaceSink entirely.
*/
class PalettedSurfaceSink final : public AbstractSurfaceSink {
public:
bool IsValidPalettedPipe() const override { return true; }
nsresult Configure(const PalettedSurfaceConfig& aConfig);
protected:
uint8_t* GetRowPointer() const override;
private:
/**
* The surface subrect which contains data. Note that the surface size we
* actually allocate is the size of the frame rect, not the logical size of
* the surface.
*/
gfx::IntRect mFrameRect;
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_SurfacePipe_h