gecko/gfx/layers/ipc/ShmemYCbCrImage.h

118 lines
3.1 KiB
C++

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