gecko-dev/image/DecoderFactory.h

107 строки
3.7 KiB
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/* -*- Mode: C++; tab-width: 2; 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_image_DecoderFactory_h
#define mozilla_image_DecoderFactory_h
#include "mozilla/Maybe.h"
#include "mozilla/gfx/2D.h"
#include "nsCOMPtr.h"
class nsACString;
namespace mozilla {
namespace image {
class Decoder;
class RasterImage;
class SourceBuffer;
enum class DecoderType
{
PNG,
GIF,
JPEG,
BMP,
ICO,
ICON,
UNKNOWN
};
class DecoderFactory
{
public:
/// @return the type of decoder which is appropriate for @aMimeType.
static DecoderType GetDecoderType(const char* aMimeType);
/**
* Creates and initializes a decoder of type @aType. The decoder will send
* notifications to @aImage.
*
* XXX(seth): @aIsRedecode, @aImageIsTransient, and @aImageIsLocked should
* really be part of @aFlags. This requires changes to the way that decoder
* flags work, though. See bug 1185800.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aImage The image will own the decoder and which should receive
* notifications as decoding progresses.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
* @param aTargetSize If not Nothing(), the target size which the image should
* be scaled to during decoding. It's an error to specify
* a target size for a decoder type which doesn't support
* downscale-during-decode.
* @param aFlags Flags specifying what type of output the decoder should
* produce; see GetDecodeFlags() in RasterImage.h.
* @param aIsRedecode Specify 'true' if this image has been decoded before.
* @param aImageIsTransient Specify 'true' if this image is transient.
* @param aImageIsLocked Specify 'true' if this image is locked for the
* lifetime of this decoder, and should be unlocked
* when the decoder finishes.
*/
static already_AddRefed<Decoder>
CreateDecoder(DecoderType aType,
RasterImage* aImage,
SourceBuffer* aSourceBuffer,
const Maybe<gfx::IntSize>& aTargetSize,
uint32_t aFlags,
bool aIsRedecode,
bool aImageIsTransient,
bool aImageIsLocked);
/**
* Creates and initializes a metadata decoder of type @aType. This decoder
* will only decode the image's header, extracting metadata like the size of
* the image. No actual image data will be decoded and no surfaces will be
* allocated. The decoder will send notifications to @aImage.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aImage The image will own the decoder and which should receive
* notifications as decoding progresses.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
*/
static already_AddRefed<Decoder>
CreateMetadataDecoder(DecoderType aType,
RasterImage* aImage,
SourceBuffer* aSourceBuffer);
private:
virtual ~DecoderFactory() = 0;
/**
* An internal method which allocates a new decoder of the requested @aType.
*/
static already_AddRefed<Decoder> GetDecoder(DecoderType aType,
RasterImage* aImage,
bool aIsRedecode);
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_DecoderFactory_h