content/renderer/render_widget_screen_metrics_emulator.h

// Copyright 2016 The Chromium 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 CONTENT_RENDERER_RENDER_WIDGET_SCREEN_METRICS_EMULATOR_H_
#define CONTENT_RENDERER_RENDER_WIDGET_SCREEN_METRICS_EMULATOR_H_

#include <memory>

#include "content/common/content_export.h"
#include "content/public/common/screen_info.h"
#include "third_party/blink/public/web/web_device_emulation_params.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"

namespace content {
class RenderWidgetScreenMetricsEmulatorDelegate;

// RenderWidgetScreenMetricsEmulator class manages screen emulation inside a
// RenderWidget. This includes resizing, placing view on the screen at desired
// position, changing device scale factor, and scaling down the whole
// widget if required to fit into the browser window.
class CONTENT_EXPORT RenderWidgetScreenMetricsEmulator {
 public:
  RenderWidgetScreenMetricsEmulator(
      RenderWidgetScreenMetricsEmulatorDelegate* delegate,
      const ScreenInfo& screen_info,
      const gfx::Size& widget_size,
      const gfx::Size& visible_viewport_size,
      const gfx::Rect& view_screen_rect,
      const gfx::Rect& window_screen_rect);
  ~RenderWidgetScreenMetricsEmulator();

  const ScreenInfo& original_screen_info() const {
    return original_screen_info_;
  }
  // This rect is the WidgetScreenRect or ViewRect, which is the main frame
  // widget's bounding box, not including OS window decor, in logical DIP screen
  // coordinates.
  const gfx::Rect& original_view_rect() const {
    return original_view_screen_rect_;
  }
  // This rect is the WindowScreenRect or WindowRect, which is the bounding box
  // of the main frame's top level window, including OS window decor, in logical
  // DIP screen coordinates.
  const gfx::Rect& original_window_rect() const {
    return original_window_screen_rect_;
  }

  float scale() const { return emulation_params_.scale; }

  // Emulated position of the main frame widget (aka view) rect.
  gfx::Point ViewRectOrigin();

  // Disables emulation and applies non-emulated values to the RenderWidget.
  // Call this before destroying the RenderWidgetScreenMetricsEmulator.
  void DisableAndApply();

  // Sets new parameters and applies them to the RenderWidget.
  void ChangeEmulationParams(const blink::WebDeviceEmulationParams& params);

  void OnSynchronizeVisualProperties(const ScreenInfo& screen_info,
                                     const gfx::Size& widget_size,
                                     const gfx::Size& visible_viewport_size);
  void OnUpdateScreenRects(const gfx::Rect& view_screen_rect,
                           const gfx::Rect& window_screen_rect);

 private:
  bool emulating_desktop() const {
    return emulation_params_.screen_position ==
           blink::WebDeviceEmulationParams::kDesktop;
  }

  // Applies emulated values to the RenderWidget.
  void Apply();

  RenderWidgetScreenMetricsEmulatorDelegate* const delegate_;

  // Parameters as passed by RenderWidget::EnableScreenMetricsEmulation.
  blink::WebDeviceEmulationParams emulation_params_;

  // Original values to restore back after emulation ends.
  ScreenInfo original_screen_info_;
  gfx::Size original_widget_size_;
  gfx::Size original_visible_viewport_size_;
  gfx::Rect original_view_screen_rect_;
  gfx::Rect original_window_screen_rect_;

  DISALLOW_COPY_AND_ASSIGN(RenderWidgetScreenMetricsEmulator);
};

}  // namespace content

#endif  // CONTENT_RENDERER_RENDER_WIDGET_SCREEN_METRICS_EMULATOR_H_