src/cobalt/system_window/system_window.h

/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef COBALT_SYSTEM_WINDOW_SYSTEM_WINDOW_H_
#define COBALT_SYSTEM_WINDOW_SYSTEM_WINDOW_H_

#include <string>

#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "base/optional.h"
#include "cobalt/base/event_dispatcher.h"
#include "cobalt/math/size.h"

namespace cobalt {
namespace system_window {

// A SystemWindow represents a window on desktop systems as well as
// as a mechanism for routing system events and notifications.
// The SystemWindow routes callbacks for user input, and provides the
// information necessary to create a display render target for a graphics
// system. A SystemWindow is typically created via a call to
// CreateSystemWindow(), which should be implemented on every Cobalt
// platform.
class SystemWindow {
 public:
  // Enumeration of possible responses for the dialog callback.
  enum DialogResponse {
    kDialogPositiveResponse,
    kDialogNegativeResponse,
    kDialogCancelResponse
  };

  // Type of callback to run when user closes a dialog.
  typedef base::Callback<void(DialogResponse response)> DialogCallback;

  // Enumeration of possible message codes for a dialog.
  enum DialogMessageCode {
    kDialogConnectionError,
    kDialogUserSignedOut,
    kDialogUserAgeRestricted
  };

  // Options structure for dialog creation. It is expected that each platform
  // will implement a modal dialog with possible support for:
  // A message code specifying the text to be displayed, which should be
  // localized according to the platform.
  // A callback indicating the user's response: positive, negative or cancel.
  struct DialogOptions {
    DialogMessageCode message_code;
    DialogCallback callback;
  };

  explicit SystemWindow(base::EventDispatcher* event_dispatcher)
      : event_dispatcher_(event_dispatcher) {}
  virtual ~SystemWindow();

  // Launches a system dialog.
  virtual void ShowDialog(const DialogOptions& options);

  // Returns the dimensions of the window.
  virtual math::Size GetWindowSize() const = 0;

  // video pixel ratio = resolution of video output / resolution of window.  Its
  // value is usually 1.0.  Set it to a value greater than 1.0 allows the video
  // to be played in higher resolution than the window.
  virtual float GetVideoPixelRatio() const { return 1.f; }

  base::EventDispatcher* event_dispatcher() const { return event_dispatcher_; }

 private:
  base::EventDispatcher* event_dispatcher_;
};

// The implementation of this function should be platform specific, and will
// create and return a platform-specific system window object. The system
// window object routes callbacks for user input and provides the information
// necessary to create a display render target for a graphics system.
// Explicitly setting a window size will result in the system attempting to
// accommmodate the preferred size, but not all systems may be able to
// fulfill the request.  |window_size| can be left blank to let the system
// choose a default window size.
scoped_ptr<SystemWindow> CreateSystemWindow(
    base::EventDispatcher*, const base::optional<math::Size>& window_size);

}  // namespace system_window
}  // namespace cobalt

#endif  // COBALT_SYSTEM_WINDOW_SYSTEM_WINDOW_H_