gtkradiant/tools/urt/libs/gtkutil/xorrectangle.h

#if !defined ( INCLUDED_XORRECTANGLE_H )
#define INCLUDED_XORRECTANGLE_H

#include <gtk/gtkwidget.h>
#include "math/vector.h"

class rectangle_t
{
public:
rectangle_t()
	: x( 0 ), y( 0 ), w( 0 ), h( 0 )
{}
rectangle_t( float _x, float _y, float _w, float _h )
	: x( _x ), y( _y ), w( _w ), h( _h )
{}
float x;
float y;
float w;
float h;
};

struct Coord2D
{
	float x, y;
	Coord2D( float _x, float _y )
		: x( _x ), y( _y ){
	}
};

inline Coord2D coord2d_device2screen( const Coord2D& coord, unsigned int width, unsigned int height ){
	return Coord2D( ( ( coord.x + 1.0f ) * 0.5f ) * width, ( ( coord.y + 1.0f ) * 0.5f ) * height );
}

inline rectangle_t rectangle_from_area( const float min[2], const float max[2], unsigned int width, unsigned int height ){
	Coord2D botleft( coord2d_device2screen( Coord2D( min[0], min[1] ), width, height ) );
	Coord2D topright( coord2d_device2screen( Coord2D( max[0], max[1] ), width, height ) );
	return rectangle_t( botleft.x, botleft.y, topright.x - botleft.x, topright.y - botleft.y );
}

class XORRectangle
{

rectangle_t m_rectangle;

GtkWidget* m_widget;
GdkGC* m_gc;

bool initialised() const {
	return m_gc != 0;
}
void lazy_init(){
	if ( !initialised() ) {
		m_gc = gdk_gc_new( m_widget->window );

		GdkColor color = { 0, 0xffff, 0xffff, 0xffff, };
		GdkColormap* colormap = gdk_window_get_colormap( m_widget->window );
		gdk_colormap_alloc_color( colormap, &color, FALSE, TRUE );
		gdk_gc_copy( m_gc, m_widget->style->white_gc );
		gdk_gc_set_foreground( m_gc, &color );
		gdk_gc_set_background( m_gc, &color );

		gdk_gc_set_function( m_gc, GDK_INVERT );
	}
}
void draw() const {
	const int x = float_to_integer( m_rectangle.x );
	const int y = float_to_integer( m_rectangle.y );
	const int w = float_to_integer( m_rectangle.w );
	const int h = float_to_integer( m_rectangle.h );
	gdk_draw_rectangle( m_widget->window, m_gc, FALSE, x, -( h ) - ( y - m_widget->allocation.height ), w, h );
}

public:
XORRectangle( GtkWidget* widget ) : m_widget( widget ), m_gc( 0 ){
}
~XORRectangle(){
	if ( initialised() ) {
		gdk_gc_unref( m_gc );
	}
}
void set( rectangle_t rectangle ){
	if ( GTK_WIDGET_REALIZED( m_widget ) ) {
		lazy_init();
		draw();
		m_rectangle = rectangle;
		draw();
	}
}
};


#endif