A cheap and cheerful GL display window using X and the GLX library. More...

#include <videodisplay.h>

Collaboration diagram for CVD::VideoDisplay:

Public Member Functions
	VideoDisplay (double left, double top, double right, double bottom, double scale=1, int *visualAttr=defAttr, bool map=true)
	Construct (and display) a display window. More...

	VideoDisplay (ImageRef size, const DoNotMapStruct &, int *visualAttr=defAttr)
	Construct (and display) a display window. More...

	VideoDisplay (ImageRef size, double scale=1, int *visualAttr=defAttr)
	Construct (and display) a display window. More...

	~VideoDisplay ()
	Destructor. This also removes the window from the display.

void	set_title (const std::string &s)
	Set the window title. More...

int	get_fd ()
	Returns the connection number for this display.

void	select_events (long event_mask)
	Select which X events to handle (by default, nothing is handled) More...

void	get_event (XEvent *event)
	Get the next X event from the queue by calling XNextEvent. More...

void	locate_display_pointer (int &x, int &y)
	Where is the mouse pointer in the window? More...

void	locate_video_pointer (double &x, double &y)
	Where is the mouse pointer in local GL co-ordinates? More...

void	flush ()
	Flushes the output buffer by calling XFlush.

int	pending ()
	How many events are waiting the queue?

void	set_zoom (double left, double top, double right, double bottom, double scale)
	Set the desired mapping between local GL and image co-ordinates. More...

void	zoom_in (double cx, double cy, double factor=2)
	Change the image mapping to zoom in around the specified point. More...

void	zoom_out (double cx, double cy, double factor=2)
	Change the image mapping to zoom out around the specified point. More...

void	zoom_reset ()
	Reset the image mapping to that when the VideoDisplay was created.

double	video_width () const
	What is the width of the local GL co-ordinates displayed?

double	video_height () const
	What is the height of the local GL co-ordinates displayed?

void	display_to_video (int dx, int dy, double &vx, double &vy)
	Convert image co-ordinates into local GL co-ordinates. More...

void	video_to_display (double dx, double dy, int &vx, int &vy)
	Convert local GL co-ordinates into image co-ordinates. More...

void	make_current ()
	Make this window the current GL context. More...

void	swap_buffers ()
	Swap the front and back GL buffers. More...

Display *	display ()
	What is my display?

Window	window ()
	Which is my window?

Static Public Attributes
static const DoNotMapStruct	DoNotMap

Related Functions
(Note that these are not member functions.)
int	defAttr []
	The default GLX display request, corresponding to the minimum specification Gl display visual (8-bit colour) More...

Detailed Description

A cheap and cheerful GL display window using X and the GLX library.

VideoDisplay maintains for you the mapping between your choice of local GL co-ordinates, and image co-ordinates and provides functions for converting between the two. It does not, however, manage any X events, for example resize or redraw events. To develop a more sophisticated display window, you must select which XEvents to monitor using select_events() and then poll using pending() and use get_event() to handle events.

Constructor & Destructor Documentation

◆ VideoDisplay() [1/3]

CVD::VideoDisplay::VideoDisplay	(	double	left,
		double	top,
		double	right,
		double	bottom,
		double	scale = `1`,
		int *	visualAttr = `defAttr`,
		bool	map = `true`
	)

Construct (and display) a display window.

Parameters

left	The local GL co-ordinate of the left of the window
top	The local GL co-ordinate of the top of the window
right	The local GL co-ordinate of the right of the window
bottom	The local GL co-ordinate of bottom of the window
scale	The number of image pixels per GL unit (default 1:1)
visualAttr	The attributes passed to glXChooseVisual
map	Whether or not to map the window

◆ VideoDisplay() [2/3]

CVD::VideoDisplay::VideoDisplay	(	ImageRef	size,
		const DoNotMapStruct &	,
		int *	visualAttr = `defAttr`
	)

Construct (and display) a display window.

Parameters

size	The GL co-ordinate window goes from (0,0) to (size.x, size.y)
map	Whether or not to map the window
visualAttr	The attributes passed to glXChooseVisual

◆ VideoDisplay() [3/3]

CVD::VideoDisplay::VideoDisplay	(	ImageRef	size,
		double	scale = `1`,
		int *	visualAttr = `defAttr`
	)

Construct (and display) a display window.

Parameters

size	The GL co-ordinate window goes from (0,0) to (size.x, size.y)
scale	The number of image pixels per GL unit (default 1:1)
visualAttr	The attributes passed to glXChooseVisual

Member Function Documentation

◆ display_to_video()

void CVD::VideoDisplay::display_to_video	(	int	dx,
		int	dy,
		double &	vx,
		double &	vy
	)

Convert image co-ordinates into local GL co-ordinates.

Parameters

dx	The image x co-ordinate to convert
dy	The image y co-ordinate to convert
vx	The returned local GL x co-ordinate
vy	The returned local GL y co-ordinate

◆ get_event()

void CVD::VideoDisplay::get_event ( XEvent * event )

Get the next X event from the queue by calling XNextEvent.

If the queue is empty, this function blocks until the next event

Parameters

event The next event

◆ locate_display_pointer()

void CVD::VideoDisplay::locate_display_pointer	(	int &	x,
		int &	y
	)

Where is the mouse pointer in the window?

Parameters

x	The x co-ordinate
y	The y co-ordinate

◆ locate_video_pointer()

void CVD::VideoDisplay::locate_video_pointer	(	double &	x,
		double &	y
	)

Where is the mouse pointer in local GL co-ordinates?

Parameters

x	The x co-ordinate
y	The y co-ordinate

◆ make_current()

void CVD::VideoDisplay::make_current ( )

Make this window the current GL context.

If there is more than one GL window being used in your program, this function should be called before drawing to ensure you draw to the correct window.

◆ select_events()

void CVD::VideoDisplay::select_events ( long event_mask )

Select which X events to handle (by default, nothing is handled)

Parameters

event_mask ORed list of XEvents to handle

◆ set_title()

void CVD::VideoDisplay::set_title ( const std::string & s )

Set the window title.

Parameters

s	The new title

◆ set_zoom()

void CVD::VideoDisplay::set_zoom	(	double	left,
		double	top,
		double	right,
		double	bottom,
		double	scale
	)

Set the desired mapping between local GL and image co-ordinates.

Parameters

left	The local GL co-ordinate of the left of the window
top	The local GL co-ordinate of the top of the window
right	The local GL co-ordinate of the right of the window
bottom	The local GL co-ordinate of bottom of the window
scale	The number if image pixels per GL unit

◆ swap_buffers()

void CVD::VideoDisplay::swap_buffers ( )

Swap the front and back GL buffers.

This calls glXSwapBuffers for the current context.

◆ video_to_display()

void CVD::VideoDisplay::video_to_display	(	double	dx,
		double	dy,
		int &	vx,
		int &	vy
	)

Convert local GL co-ordinates into image co-ordinates.

Parameters

dx	The local GL x co-ordinate to convert
dy	The local GL y co-ordinate to convert
vx	The returned image x co-ordinate
vy	The returned image y co-ordinate

◆ zoom_in()

void CVD::VideoDisplay::zoom_in	(	double	cx,
		double	cy,
		double	factor = `2`
	)

Change the image mapping to zoom in around the specified point.

Parameters

cx	The x co-ordinate of the zoom centre
cy	The y co-ordinate of the zoom centre
factor	The zoom factor (default 2)

◆ zoom_out()

void CVD::VideoDisplay::zoom_out	(	double	cx,
		double	cy,
		double	factor = `2`
	)

inline

Change the image mapping to zoom out around the specified point.

Parameters

cx	The x co-ordinate of the zoom centre
cy	The y co-ordinate of the zoom centre
factor	The zoom factor (default 2)

Friends And Related Function Documentation

◆ defAttr

int defAttr[]

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

cvd/videodisplay.h
cvd_src/videodisplay.cc

Public Member Functions

Static Public Attributes

Related Functions

Detailed Description

Constructor & Destructor Documentation

◆ VideoDisplay() [1/3]

◆ VideoDisplay() [2/3]

◆ VideoDisplay() [3/3]

Member Function Documentation

◆ display_to_video()

◆ get_event()

◆ locate_display_pointer()

◆ locate_video_pointer()

◆ make_current()

◆ select_events()

◆ set_title()

◆ set_zoom()

◆ swap_buffers()

◆ video_to_display()

◆ zoom_in()

◆ zoom_out()

Friends And Related Function Documentation

◆ defAttr