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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef FLUTTER_SHELL_COMMON_DISPLAY_H_
#define FLUTTER_SHELL_COMMON_DISPLAY_H_
#include <optional>
#include "flutter/fml/macros.h"
#include "flutter/shell/common/variable_refresh_rate_reporter.h"
namespace flutter {
/// Unique ID per display that is stable until the Flutter application restarts.
/// See also: `flutter::Display`
typedef uint64_t DisplayId;
/// To be used when the display refresh rate is unknown.
static constexpr double kUnknownDisplayRefreshRate = 0;
/// Display refers to a graphics hardware system consisting of a framebuffer,
/// typically a monitor or a screen. This class holds the various display
/// settings.
class Display {
public:
//------------------------------------------------------------------------------
/// @brief Construct a new Display object in case where the display id of the
/// display is known. In cases where there is more than one display, every
/// display is expected to have a display id.
///
Display(DisplayId display_id, double refresh_rate)
: display_id_(display_id), refresh_rate_(refresh_rate) {}
//------------------------------------------------------------------------------
/// @brief Construct a new Display object when there is only a single display.
/// When there are multiple displays, every display must have a display id.
///
explicit Display(double refresh_rate)
: display_id_({}), refresh_rate_(refresh_rate) {}
virtual ~Display() = default;
// Get the display's maximum refresh rate in the unit of frame per second.
// Return `kUnknownDisplayRefreshRate` if the refresh rate is unknown.
virtual double GetRefreshRate() const;
/// Returns the `DisplayId` of the display.
std::optional<DisplayId> GetDisplayId() const { return display_id_; }
private:
std::optional<DisplayId> display_id_;
double refresh_rate_;
FML_DISALLOW_COPY_AND_ASSIGN(Display);
};
} // namespace flutter
#endif // FLUTTER_SHELL_COMMON_DISPLAY_H_