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71 lines
2.2 KiB
C++
71 lines
2.2 KiB
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef FLUTTER_SHELL_COMMON_VSYNC_WAITER_H_
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#define FLUTTER_SHELL_COMMON_VSYNC_WAITER_H_
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#include <functional>
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#include <memory>
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#include <mutex>
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#include "flutter/common/task_runners.h"
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#include "flutter/fml/time/time_point.h"
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namespace flutter {
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/// Abstract Base Class that represents a platform specific mechanism for
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/// getting callbacks when a vsync event happens.
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class VsyncWaiter : public std::enable_shared_from_this<VsyncWaiter> {
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public:
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using Callback = std::function<void(fml::TimePoint frame_start_time,
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fml::TimePoint frame_target_time)>;
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virtual ~VsyncWaiter();
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void AsyncWaitForVsync(const Callback& callback);
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/// Add a secondary callback for the next vsync.
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///
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/// See also |PointerDataDispatcher::ScheduleSecondaryVsyncCallback|.
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void ScheduleSecondaryCallback(const fml::closure& callback);
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static constexpr float kUnknownRefreshRateFPS = 0.0;
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// Get the display's maximum refresh rate in the unit of frame per second.
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// Return kUnknownRefreshRateFPS if the refresh rate is unknown.
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virtual float GetDisplayRefreshRate() const;
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protected:
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// On some backends, the |FireCallback| needs to be made from a static C
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// method.
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friend class VsyncWaiterAndroid;
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friend class VsyncWaiterEmbedder;
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const TaskRunners task_runners_;
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VsyncWaiter(TaskRunners task_runners);
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// Implementations are meant to override this method and arm their vsync
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// latches when in response to this invocation. On vsync, they are meant to
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// invoke the |FireCallback| method once (and only once) with the appropriate
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// arguments. This method should not block the current thread.
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virtual void AwaitVSync() = 0;
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void FireCallback(fml::TimePoint frame_start_time,
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fml::TimePoint frame_target_time);
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private:
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std::mutex callback_mutex_;
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Callback callback_;
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std::mutex secondary_callback_mutex_;
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fml::closure secondary_callback_;
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FML_DISALLOW_COPY_AND_ASSIGN(VsyncWaiter);
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};
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} // namespace flutter
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#endif // FLUTTER_SHELL_COMMON_VSYNC_WAITER_H_
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