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118 lines
3.1 KiB
C++
118 lines
3.1 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_LAYERS_SHMEMYCBCRIMAGE_H
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#define MOZILLA_LAYERS_SHMEMYCBCRIMAGE_H
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#include "mozilla/DebugOnly.h"
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#include "base/basictypes.h"
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#include "Shmem.h"
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#include "gfxPoint.h"
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namespace mozilla {
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namespace ipc {
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class Shmem;
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}
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namespace layers {
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/**
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* This class is a view on a YCbCrImage stored in a Shmem at a certain offset.
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* It is only meant as a convenience to access the image data, and does not own
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* the data. The instance can live on the stack and used as follows:
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*
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* const YCbCrImage& yuv = sharedImage.get_YCbCrImage();
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* ShmemYCbCrImage shmImg(yuv.data(), yuv.offset());
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* if (!shmImg.IsValid()) {
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* // handle error
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* }
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* mYSize = shmImg.GetYSize(); // work with the data, etc...
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*/
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class ShmemYCbCrImage
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{
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public:
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typedef mozilla::ipc::Shmem Shmem;
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ShmemYCbCrImage() : mOffset(0) {}
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ShmemYCbCrImage(Shmem& shm, size_t offset = 0) {
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DebugOnly<bool> status = Open(shm,offset);
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NS_ASSERTION(status, "Invalid data in the shmem");
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}
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/**
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* This function is meant as a helper to know how much shared memory we need
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* to allocate in a shmem in order to place a shared YCbCr image blob of
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* given dimensions.
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*/
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static size_t ComputeMinBufferSize(const gfxIntSize& aYSize,
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const gfxIntSize& aCbCrSize);
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/**
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* Write the image informations in a buffer for given dimensions.
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* The provided pointer should point to the beginning of the (chunk of)
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* buffer on which we want to store th image.
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*/
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static void InitializeBufferInfo(uint8_t* aBuffer,
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const gfxIntSize& aYSize,
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const gfxIntSize& aCbCrSize);
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/**
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* Returns true if the shmem's data blob contains a valid YCbCr image.
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*/
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bool IsValid();
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/**
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* Returns the Y channel data pointer.
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*/
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uint8_t* GetYData();
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/**
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* Returns the Cb channel data pointer.
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*/
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uint8_t* GetCbData();
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/**
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* Returns the Cr channel data pointer.
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*/
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uint8_t* GetCrData();
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/**
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* Returns the Y channel stride.
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*/
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uint32_t GetYStride();
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/**
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* Returns the stride of the Cb and Cr channels.
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*/
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uint32_t GetCbCrStride();
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/**
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* Returns the dimensions of the Y Channel.
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*/
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gfxIntSize GetYSize();
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/**
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* Returns the dimensions of the Cb and Cr Channel.
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*/
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gfxIntSize GetCbCrSize();
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/**
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* Copies the data passed in parameter into the shmem.
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*/
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bool CopyData(const uint8_t* aYData,
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const uint8_t* aCbData, const uint8_t* aCrData,
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gfxIntSize aYSize, uint32_t aYStride,
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gfxIntSize aCbCrSize, uint32_t aCbCrStride,
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uint32_t aYSkip, uint32_t aCbCrSkip);
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private:
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bool Open(Shmem& aShmem, size_t aOffset = 0);
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ipc::Shmem mShmem;
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size_t mOffset;
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};
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} // namespace
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} // namespace
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#endif
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