gecko-dev/gfx/layers/CanvasRenderer.h

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/* -*- 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/. */
#ifndef GFX_CANVASRENDERER_H
#define GFX_CANVASRENDERER_H
#include <stdint.h> // for uint32_t
#include "GLContextTypes.h" // for GLContext
#include "gfxContext.h" // for gfxContext, etc
#include "gfxTypes.h"
#include "gfxPlatform.h" // for gfxImageFormat
#include "mozilla/Assertions.h" // for MOZ_ASSERT, etc
#include "mozilla/Preferences.h" // for Preferences
#include "mozilla/RefPtr.h" // for RefPtr
#include "mozilla/gfx/2D.h" // for DrawTarget
#include "mozilla/mozalloc.h" // for operator delete, etc
#include "nsISupportsImpl.h" // for MOZ_COUNT_CTOR, etc
namespace mozilla {
namespace layers {
class AsyncCanvasRenderer;
class ClientCanvasRenderer;
class CopyableCanvasRenderer;
class PersistentBufferProvider;
class WebRenderCanvasRendererAsync;
struct CanvasInitializeData {
CanvasInitializeData()
: mBufferProvider(nullptr)
, mGLContext(nullptr)
, mRenderer(nullptr)
, mPreTransCallback(nullptr)
, mPreTransCallbackData(nullptr)
, mDidTransCallback(nullptr)
, mDidTransCallbackData(nullptr)
, mFrontbufferGLTex(0)
, mSize(0,0)
, mHasAlpha(false)
, mIsGLAlphaPremult(true)
{ }
// One of these three must be specified for Canvas2D, but never more than one
PersistentBufferProvider* mBufferProvider; // A BufferProvider for the Canvas contents
mozilla::gl::GLContext* mGLContext; // or this, for GL.
AsyncCanvasRenderer* mRenderer; // or this, for OffscreenCanvas
typedef void (* TransactionCallback)(void* closureData);
TransactionCallback mPreTransCallback;
void* mPreTransCallbackData;
TransactionCallback mDidTransCallback;
void* mDidTransCallbackData;
// Frontbuffer override
uint32_t mFrontbufferGLTex;
// The size of the canvas content
gfx::IntSize mSize;
// Whether the canvas drawingbuffer has an alpha channel.
bool mHasAlpha;
// Whether mGLContext contains data that is alpha-premultiplied.
bool mIsGLAlphaPremult;
};
// Based class which used for canvas rendering. There are many derived classes for
// different purposes. such as:
//
// CopyableCanvasRenderer provides a utility which readback canvas content to a
// SourceSurface. BasicCanvasLayer uses CopyableCanvasRenderer.
//
// ShareableCanvasRenderer provides IPC capabilities that allow sending canvas
// content over IPC. This is pure virtual class because the IPC handling is
// different in different LayerManager. So that we have following classes inherite
// ShareableCanvasRenderer.
//
// ClientCanvasRenderer inherites ShareableCanvasRenderer and be used in
// ClientCanvasLayer.
// WebRenderCanvasRenderer inherites ShareableCanvasRenderer and provides all
// functionality that WebRender uses.
// WebRenderCanvasRendererAsync inherites WebRenderCanvasRenderer and be used in
// layers-free mode of WebRender.
//
// class diagram shows below:
//
// +--------------+
// |CanvasRenderer|
// +-------+------+
// ^
// |
// +----------------------+
// |CopyableCanvasRenderer|
// +----------------------+
// ^
// |
// +-----------+-----------+
// |ShareableCanvasRenderer|
// +-----+-----------------+
// ^ ^
// +-------------+ +-------+
// | |
// +--------------------+ +---------+-------------+
// |ClientCanvasRenderer| |WebRenderCanvasRenderer|
// +--------------------+ +-----------+-----------+
// ^
// |
// +-------------+--------------+
// |WebRenderCanvasRendererAsync|
// +----------------------------+
class CanvasRenderer
{
public:
CanvasRenderer();
virtual ~CanvasRenderer();
public:
virtual void Initialize(const CanvasInitializeData& aData);
virtual bool IsDataValid(const CanvasInitializeData& aData) { return true; }
virtual void ClearCachedResources() { }
virtual void Destroy() { }
const gfx::IntSize& GetSize() const { return mSize; }
void SetDirty() { mDirty = true; }
void ResetDirty() { mDirty = false; }
bool IsDirty() const { return mDirty; }
virtual CopyableCanvasRenderer* AsCopyableCanvasRenderer() { return nullptr; }
virtual ClientCanvasRenderer* AsClientCanvasRenderer() { return nullptr; }
virtual WebRenderCanvasRendererAsync* AsWebRenderCanvasRendererAsync() { return nullptr; }
protected:
void FirePreTransactionCallback()
{
if (mPreTransCallback) {
mPreTransCallback(mPreTransCallbackData);
}
}
void FireDidTransactionCallback()
{
if (mDidTransCallback) {
mDidTransCallback(mDidTransCallbackData);
}
}
typedef void (* TransactionCallback)(void* closureData);
TransactionCallback mPreTransCallback;
void* mPreTransCallbackData;
TransactionCallback mDidTransCallback;
void* mDidTransCallbackData;
gfx::IntSize mSize;
private:
/**
* Set to true in Updated(), cleared during a transaction.
*/
bool mDirty;
};
} // namespace layers
} // namespace mozilla
#endif