Manages the transformations between coordinate systems. More...

#include <camera.hpp>

Public Member Functions
point2d	world_to_screen (point2d world_coordinates) const
	Convert a point in world coordinates to screen coordinates.

point2d	widget_to_screen (point2d widget_coordinates) const
	Convert a point in widget coordinates to screen coordinates.

point2d	widget_to_world (point2d widget_coordinates) const
	Convert a point in widget coordinates to world coordinates.

rectangle	get_world () const
	Get the currently visible bounds of the world.

rectangle	get_screen () const
	Get the dimensions of the screen.

rectangle	get_widget () const
	Get the dimensions of the widget.

rectangle	get_initial_world () const
	Get the initial bounds of the world. More...

void	set_world (rectangle new_world)
	Update the visible bounds of the world. More...

void	reset_world (rectangle new_world)
	Reset the world coordinates. More...

point2d	get_world_scale_factor () const
	Get the screen to world scaling factor.

Protected Member Functions
	camera (rectangle bounds)
	Create a camera. More...

void	update_widget (int width, int height)
	Update the dimensions of the widget. More...

void	update_scale_factors ()
	Update the scaling factors.

Friends
class	canvas

Detailed Description

Manages the transformations between coordinate systems.

Application code doesn't (and can't) call these functions; they are for ezgl internal use.

The camera class manages transformations between a GTK widget, world, and "screen" coordinate system. A GTK widget has dimensions that change based on the user, and its aspect ratio may not match the world coordinate system. The camera maintains a "screen" within the widget that keeps the same aspect ratio as the world coordinate system, regardless of the dimensions of the widget.

A camera object can only be created by an ezgl::canvas object, who has the responsibility of updating the camera with changes to the widget's dimensions. The only state that can be mutated outside the library is the camera's world coordinate system.

Constructor & Destructor Documentation

◆ camera()

ezgl::camera::camera ( rectangle bounds )

explicitprotected

Create a camera.

Parameters

bounds The initial bounds of the coordinate system.

Member Function Documentation

◆ get_initial_world()

rectangle ezgl::camera::get_initial_world ( ) const

inline

Get the initial bounds of the world.

Needed for zoom_fit

◆ reset_world()

void ezgl::camera::reset_world ( rectangle new_world )

Reset the world coordinates.

Used by change_canvas_world_coordinates().

◆ set_world()

void ezgl::camera::set_world ( rectangle new_world )

Update the visible bounds of the world.

Used in panning and zooming.

◆ update_widget()

void ezgl::camera::update_widget	(	int	width,
		int	height
	)

protected

Update the dimensions of the widget.

This will change the screen where the world is projected. The screen will maintain the aspect ratio of the world's coordinate system while being centered within the screen.

See also: canvas::configure_event

The documentation for this class was generated from the following file:

camera.hpp

Public Member Functions

Protected Member Functions

Friends