gecko/gfx/2d/DataSurfaceHelpers.h
Nathan Froyd d9e6000c7f Bug 1218488 - clarify buffer ownership for nsICanvasRenderingContextInternal::GetBuffer; r=Bas,baku
This patch started life as making ImageEncoder.cpp:EncodingRunnable not
use nsAutoArrayPtr, but the API effects rippled out from there.  On the
whole, I think using UniquePtr throughout has made the code clearer.
2015-10-26 14:31:12 -04:00

109 lines
3.5 KiB
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/* -*- 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_GFX_DATASURFACEHELPERS_H
#define _MOZILLA_GFX_DATASURFACEHELPERS_H
#include "2D.h"
#include "mozilla/UniquePtr.h"
namespace mozilla {
namespace gfx {
void
ConvertBGRXToBGRA(uint8_t* aData, const IntSize &aSize, const int32_t aStride);
/**
* Copy the pixel data from aSrc and pack it into aDst. aSrcSize, aSrcStride
* and aBytesPerPixel give the size, stride and bytes per pixel for aSrc's
* surface. Callers are responsible for making sure that aDst is big enough to
* contain |aSrcSize.width * aSrcSize.height * aBytesPerPixel| bytes.
*/
void
CopySurfaceDataToPackedArray(uint8_t* aSrc, uint8_t* aDst, IntSize aSrcSize,
int32_t aSrcStride, int32_t aBytesPerPixel);
/**
* Convert aSurface to a packed buffer in BGRA format.
*/
UniquePtr<uint8_t[]>
SurfaceToPackedBGRA(DataSourceSurface *aSurface);
/**
* Convert aSurface to a packed buffer in BGR format. The pixel data is
* returned in a buffer allocated with new uint8_t[]. The caller then has
* ownership of the buffer and is responsible for delete[]'ing it.
*
* This function is currently only intended for use with surfaces of format
* SurfaceFormat::B8G8R8X8 since the X components of the pixel data (if any)
* are simply dropped (no attempt is made to un-pre-multiply alpha from the
* color components).
*/
uint8_t*
SurfaceToPackedBGR(DataSourceSurface *aSurface);
/**
* Clears all the bytes in a DataSourceSurface's data array to zero (so to
* transparent black for SurfaceFormat::B8G8R8A8, for example).
* Note that DataSourceSurfaces can be initialized to zero, which is
* more efficient than zeroing the surface after initialization.
*/
void
ClearDataSourceSurface(DataSourceSurface *aSurface);
/**
* Multiplies aStride and aHeight and makes sure the result is limited to
* something sane. To keep things consistent, this should always be used
* wherever we allocate a buffer based on surface stride and height.
*
* @param aExtra Optional argument to specify an additional number of trailing
* bytes (useful for creating intermediate surfaces for filters, for
* example).
*
* @return The result of the multiplication if it is acceptable, or else zero.
*/
size_t
BufferSizeFromStrideAndHeight(int32_t aStride,
int32_t aHeight,
int32_t aExtraBytes = 0);
/**
* Copy aSrcRect from aSrc to aDest starting at aDestPoint.
*/
void
CopyRect(DataSourceSurface* aSrc, DataSourceSurface* aDest,
IntRect aSrcRect, IntPoint aDestPoint);
/**
* Create a non aliasing copy of aSource. This creates a new DataSourceSurface
* using the factory and copies the bits.
*
* @return a dss allocated by Factory that contains a copy a aSource.
*/
already_AddRefed<DataSourceSurface>
CreateDataSourceSurfaceByCloning(DataSourceSurface* aSource);
/**
* Return the byte at aPoint.
*/
uint8_t*
DataAtOffset(DataSourceSurface* aSurface,
DataSourceSurface::MappedSurface* aMap,
IntPoint aPoint);
/**
* Check if aPoint is contained by the surface.
*
* @returns true if and only if aPoint is inside the surface.
*/
bool
SurfaceContainsPoint(SourceSurface* aSurface, const IntPoint& aPoint);
} // namespace gfx
} // namespace mozilla
#endif // _MOZILLA_GFX_DATASURFACEHELPERS_H