camera.hpp

/*
 * Copyright 2019-2022 University of Toronto
 *
 * 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.
 *
 * Authors: Mario Badr, Sameh Attia, Tanner Young-Schultz and Vaughn Betz
 */
 
#ifndef EZGL_CAMERA_HPP
#define EZGL_CAMERA_HPP
 
#include "ezgl/point.hpp"
#include "ezgl/rectangle.hpp"
 
namespace ezgl {
 
class camera {
public:
  point2d world_to_screen(point2d world_coordinates) const;
 
  point2d widget_to_screen(point2d widget_coordinates) const;
 
  point2d widget_to_world(point2d widget_coordinates) const;
 
  rectangle get_world() const
  {
    return m_world;
  }
 
  rectangle get_screen() const
  {
    return m_screen;
  }
 
  rectangle get_widget() const
  {
    return m_widget;
  }
 
  rectangle get_initial_world() const
  {
    return m_initial_world;
  }
 
  void set_world(rectangle new_world);
 
  void reset_world(rectangle new_world);
 
  point2d get_world_scale_factor() const
  {
    return m_screen_to_world;
  }
 
protected:
  // Only an ezgl::canvas can create a camera.
  friend class canvas;
 
  explicit camera(rectangle bounds);
 
  void update_widget(int width, int height);
 
  void update_scale_factors();
 
private:
  // The dimensions of the parent widget.
  rectangle m_widget = {{0, 0}, 1.0, 1.0};
 
  // The dimensions of the world (user-defined bounding box).
  rectangle m_world;
 
  // The dimensions of the screen, which may not match the widget.
  rectangle m_screen;
 
  // The dimensions of the initial world (user-defined bounding box). Needed for zoom_fit
  rectangle m_initial_world;
 
  // The x and y scaling factors.
  point2d m_world_to_widget = {1.0, 1.0};
  point2d m_widget_to_screen = {1.0, 1.0};
  point2d m_screen_to_world = {1.0, 1.0};
};
}
 
#endif //EZGL_CAMERA_HPP