/*
 * groupClearCairoContext
 *
 */
void groupClearCairoContext(GroupCairoContext *cc)
{
	cairo_t *cr = cc->cairo;
	cairo_save(cr);
	cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
	cairo_paint(cr);
	cairo_restore(cr);
}

/*
 * groupDestroyCairoContext
 *
 */
static void
groupDestroyCairoContext(GroupSelection *group, CompScreen *s)
{
	GroupTabBar *bar = group->tabBar;
	GroupCairoContext *cc = bar->cc;

	if (cc->cairo)
		cairo_destroy(cc->cairo);

	if (cc->surface)
		cairo_surface_destroy(cc->surface);

	if (cc->texBuf)
		free(cc->texBuf);

	if (&cc->texture)
		finiTexture(s, &cc->texture);

	free(cc);
}

/*
 * groupCreateCairoContext
 *
 */
void groupCreateCairoContext(GroupSelection *group, CompScreen *s)
{
	GroupTabBar *bar = group->tabBar;
	GroupCairoContext *cc = (GroupCairoContext*) malloc(sizeof(GroupCairoContext));

	cc->surface	= NULL;
	cc->cairo	= NULL;
	cc->texBuf  = NULL;

	int w, h;

	// thats the width & height of the texture we need
	w = group->tabBar->region->extents.x2 - group->tabBar->region->extents.x1;
	h = group->tabBar->region->extents.y2 - group->tabBar->region->extents.y1;
	
	// that a beryl intern function which initializes a CompTexture struct
	initTexture(s, &cc->texture);
	// that our image
	cc->texBuf = calloc (4 * w * h, sizeof (unsigned char));
	// here we convert it to CompTexture
	imageToTexture(s, &cc->texture, cc->texBuf, w, h);

	// creating the surface for cairo
	cc->surface = cairo_image_surface_create_for_data (cc->texBuf, CAIRO_FORMAT_ARGB32, w, h, 4 * w);

	if (cairo_surface_status(cc->surface) != CAIRO_STATUS_SUCCESS)
	{
		free(cc->texBuf);
		finiTexture(s, &cc->texture);
        printf ("create_cairo_context() - Couldn't create surface\n");
        return;
	}

	// creating the cairo handler
	cc->cairo = cairo_create(cc->surface);
	if (cairo_status(cc->cairo) != CAIRO_STATUS_SUCCESS)
	{
		free(cc->texBuf);
		finiTexture(s, &cc->texture);
        printf ("create_cairo_context() - Couldn't create context\n");
        return;
	}

	// clean the context
	groupClearCairoContext(cc);

	bar->cc = cc;
}