cairo graphics 0.4 (line work animation)



/* http://cairographics.org/threaded_animation_with_cairo/ */
/* Hack by Jeffrin Jose Licensed GPL v3 Copyright
August 2010 GPL --> http://www.gnu.org/copyleft/gpl.html */

#include
#include
#include

//the global pixmap that will serve as our buffer
static GdkPixmap *pixmap = NULL;

gboolean on_window_configure_event(GtkWidget * da,
GdkEventConfigure * event, gpointer user_data){
static int oldw = 0;
static int oldh = 0;
//make our selves a properly sized pixmap if our window has been
resized
if (oldw != event->width || oldh != event->height){
//create our new pixmap with the correct size.
GdkPixmap *tmppixmap = gdk_pixmap_new(da->window, event->width,
event->height, -1);
//copy the contents of the old pixmap to the new pixmap. This keeps
ugly uninitialized
//pixmaps from being painted upon resize
int minw = oldw, minh = oldh;
if( event->width width; }
if( event->height height; }
gdk_draw_drawable(tmppixmap, da->style-
>fg_gc[GTK_WIDGET_STATE(da)], pixmap, 0, 0, 0, 0, minw, minh);
//we're done with our old pixmap, so we can get rid of it and replace it
with our properly-sized one.
g_object_unref(pixmap);
pixmap = tmppixmap;
}
oldw = event->width;
oldh = event->height;
return TRUE;
}

gboolean on_window_expose_event(GtkWidget * da, GdkEventExpose *
event, gpointer user_data){
gdk_draw_drawable(da->window,
da->style->fg_gc[GTK_WIDGET_STATE(da)], pixmap,
// Only copy the area that was exposed.
event->area.x, event->area.y,
event->area.x, event->area.y,
event->area.width, event->area.height);
return TRUE;
}

static int currently_drawing = 0;
//do_draw will be executed in a separate thread whenever we would like
to update
//our animation
void *do_draw(void *ptr){

currently_drawing = 1;

int width, height;
gdk_threads_enter();
gdk_drawable_get_size(pixmap, &width, &height);
gdk_threads_leave();

//create a gtk-independant surface to draw on
cairo_surface_t *cst = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
width, height);
cairo_t *cr = cairo_create(cst);

//do some time-consuming drawing
static int i = 0;
++i; i = i % 300; //give a little movement to our animation
cairo_set_source_rgb (cr, .9, .9, .9);
cairo_paint(cr);
cairo_set_source_rgb (cr, 0.8, 0.5, 0.9);
cairo_move_to(cr, 50,50);

int j,k;
/* for(k=0; k<100; ++k){*/ //lets just redraw lots of times to use a
lot of proc power
for(j=0; j window,700,700,-1);
//because we will be painting our pixmap manually during expose events
//we can turn off gtk's automatic painting and double buffering routines.
gtk_widget_set_app_paintable(window, TRUE);
gtk_widget_set_double_buffered(window, FALSE);

(void)g_timeout_add(33, (GSourceFunc)timer_exe, window);

gtk_main();
gdk_threads_leave();

return 0;
}

 

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