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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 */
#ifndef mozilla_layers_ProfilerScreenshots_h
#define mozilla_layers_ProfilerScreenshots_h
#include <functional>
#include "mozilla/Mutex.h"
#include "mozilla/RefPtr.h"
#include "mozilla/TimeStamp.h"
#include "nsCOMPtr.h"
#include "nsTArray.h"
#include "mozilla/gfx/Point.h"
class nsIThread;
namespace mozilla {
namespace gfx {
class DataSourceSurface;
namespace layers {
* Can be used to submit screenshots from the compositor to the profiler.
* Screenshots have a fixed bounding size. The user of this class will usually
* scale down the window contents first, ideally on the GPU, then read back the
* small scaled down image into main memory, and then call SubmitScreenshot to
* pass the data to the profiler.
* This class encodes each screenshot to a JPEG data URL, on a separate thread.
* This class manages that thread and recycles memory buffers.
* Users of ProfilerScreenshots should have one ProfilerScreenshot instance per
* window, as a unique window id is created by the constructor.
class ProfilerScreenshots final {
* Returns whether the profiler is currently active and is running with the
* "screenshots" feature enabled.
static bool IsEnabled();
* Returns a fixed size that all screenshots should be resized to fit into.
static gfx::IntSize ScreenshotSize() { return gfx::IntSize(350, 350); }
* The main functionality provided by this class.
* This method will synchronously invoke the supplied aPopulateSurface
* callback function with a DataSourceSurface in which the callback should
* store the pixel data. This surface may be larger than aScaledSize, but
* only the data in the rectangle (0, 0, aScaledSize.width,
* aScaledSize.height) will be read.
* @param aWindowIdentifier A pointer-sized integer that can be used to match
* up multiple screenshots from the same window.
* @param aOriginalSize The unscaled size of the snapshotted window.
* @param aScaledSize The scaled size, aScaled <= ScreenshotSize(), which the
* snapshot has been resized to.
* @param aTimeStamp The time at which the snapshot was taken. In
* asynchronous readback implementations, this is the time at which the
* readback / copy command was put into the command stream to the GPU, not
* the time at which the readback data was mapped into main memory.
* @param aPopulateSurface A callback that the caller needs to implement,
* which needs to copy the screenshot pixel data into the surface that's
* supplied to the callback. Called zero or one times, synchronously.
void SubmitScreenshot(
const gfx::IntSize& aOriginalSize, const gfx::IntSize& aScaledSize,
const TimeStamp& aTimeStamp,
const std::function<bool(gfx::DataSourceSurface*)>& aPopulateSurface);
* Recycle a surface from mAvailableSurfaces or create a new one if all
* surfaces are currently in use, up to some maximum limit.
* Returns null if the limit is reached.
* Can be called on any thread.
already_AddRefed<gfx::DataSourceSurface> TakeNextSurface();
* Return aSurface back into the mAvailableSurfaces pool. Can be called on
* any thread.
void ReturnSurface(gfx::DataSourceSurface* aSurface);
// An array of surfaces ready to be recycled. Can be accessed from multiple
// threads, protected by mMutex.
nsTArray<RefPtr<gfx::DataSourceSurface>> mAvailableSurfaces;
// Protects mAvailableSurfaces.
// The total number of surfaces created. If encoding is fast enough to happen
// entirely in the time between two calls to SubmitScreenshot, this should
// never exceed 1.
uint32_t mLiveSurfaceCount;
// Window identifier used to submit screenshots, created in the constructor.
uint32_t mWindowIdentifier;
// Counter incremented each time a new instance is constructed.
static uint32_t sWindowCounter;
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_ProfilerScreenshots_h