Source code

Revision control

Copy as Markdown

Other Tools

/* -*- 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 */
#ifndef mozilla_layers_ScreenshotGrabber_h
#define mozilla_layers_ScreenshotGrabber_h
#include "nsISupportsImpl.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/Point.h"
#include "mozilla/gfx/Rect.h"
namespace mozilla {
namespace layers {
namespace profiler_screenshots {
class Window;
class RenderSource;
class DownscaleTarget;
class AsyncReadbackBuffer;
class ScreenshotGrabberImpl;
} // namespace profiler_screenshots
* Used by various renderers / layer managers to grab snapshots from the window
* and submit them to the Gecko profiler.
* Doesn't do any work if the profiler is not running or the "screenshots"
* feature is not enabled.
* Screenshots are scaled down to fit within a fixed size, and read back to
* main memory using async readback. Scaling is done in multiple scale-by-0.5x
* steps using DownscaleTarget::CopyFrom, and readback is done using
* AsyncReadbackBuffers.
class ScreenshotGrabber final {
// Scale the contents of aWindow's current render target into an
// appropriately sized DownscaleTarget and read its contents into an
// AsyncReadbackBuffer. The AsyncReadbackBuffer is not mapped into main
// memory until the second call to MaybeProcessQueue() after this call to
// MaybeGrabScreenshot().
void MaybeGrabScreenshot(profiler_screenshots::Window& aWindow,
const gfx::IntSize& aWindowSize);
// Map the contents of any outstanding AsyncReadbackBuffers from previous
// composites into main memory and submit each screenshot to the profiler.
void MaybeProcessQueue();
// Insert a special profiler marker for a composite that didn't do any actual
// compositing, so that the profiler knows why no screenshot was taken for
// this frame.
void NotifyEmptyFrame();
// Destroy all Window-related resources that this class is holding on to.
void Destroy();
// non-null while ProfilerScreenshots::IsEnabled() returns true
UniquePtr<profiler_screenshots::ScreenshotGrabberImpl> mImpl;
// Interface definitions.
namespace profiler_screenshots {
class Window {
virtual already_AddRefed<RenderSource> GetWindowContents(
const gfx::IntSize& aWindowSize) = 0;
virtual already_AddRefed<DownscaleTarget> CreateDownscaleTarget(
const gfx::IntSize& aSize) = 0;
virtual already_AddRefed<AsyncReadbackBuffer> CreateAsyncReadbackBuffer(
const gfx::IntSize& aSize) = 0;
virtual ~Window() {}
class RenderSource {
const auto& Size() const { return mSize; }
explicit RenderSource(const gfx::IntSize& aSize) : mSize(aSize) {}
virtual ~RenderSource() {}
const gfx::IntSize mSize;
class DownscaleTarget {
virtual already_AddRefed<RenderSource> AsRenderSource() = 0;
const auto& Size() const { return mSize; }
virtual bool DownscaleFrom(RenderSource* aSource,
const gfx::IntRect& aSourceRect,
const gfx::IntRect& aDestRect) = 0;
explicit DownscaleTarget(const gfx::IntSize& aSize) : mSize(aSize) {}
virtual ~DownscaleTarget() {}
const gfx::IntSize mSize;
class AsyncReadbackBuffer {
const auto& Size() const { return mSize; }
virtual void CopyFrom(RenderSource* aSource) = 0;
virtual bool MapAndCopyInto(gfx::DataSourceSurface* aSurface,
const gfx::IntSize& aReadSize) = 0;
explicit AsyncReadbackBuffer(const gfx::IntSize& aSize) : mSize(aSize) {}
virtual ~AsyncReadbackBuffer() {}
const gfx::IntSize mSize;
} // namespace profiler_screenshots
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_ScreenshotGrabber_h