#define __SP_CANVAS_UTILS_C__

/*
 * Helper stuff for SPCanvas
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *
 * Copyright (C) 1999-2002 authors
 * Copyright (C) 2001-2002 Ximian, Inc.
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include <string.h>
#include <libart_lgpl/art_misc.h>
#include <libart_lgpl/art_affine.h>
#include <libart_lgpl/art_svp.h>
#include <libart_lgpl/art_rgb_svp.h>
#include "sp-canvas-util.h"

void
sp_canvas_update_bbox (SPCanvasItem *item, int x1, int y1, int x2, int y2)
{
	sp_canvas_request_redraw (item->canvas, (int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);
	item->x1 = x1;
	item->y1 = y1;
	item->x2 = x2;
	item->y2 = y2;
	sp_canvas_request_redraw (item->canvas, (int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);
}

void
sp_canvas_item_reset_bounds (SPCanvasItem *item)
{
	item->x1 = 0.0;
	item->y1 = 0.0;
	item->x2 = 0.0;
	item->y2 = 0.0;
}

void
sp_canvas_buf_ensure_buf (SPCanvasBuf *buf)
{
	if (!buf->is_buf) {
		unsigned int r, g, b;
		int x, y;
		r = buf->bg_color >> 16;
		g = (buf->bg_color >> 8) & 0xff;
		b = buf->bg_color & 0xff;
		for (y = buf->rect.y0; y < buf->rect.y1; y++) {
			guchar *p;
			p = buf->buf + (y - buf->rect.y0) * buf->buf_rowstride;
			for (x = buf->rect.x0; x < buf->rect.x1; x++) {
				*p++ = r;
				*p++ = g;
				*p++ = b;
			}
		}
		buf->is_buf = 1;
	}
}

void
sp_canvas_clear_buffer (SPCanvasBuf *buf)
{
	unsigned char r, g, b;

	r = (buf->bg_color >> 16) & 0xff;
	g = (buf->bg_color >> 8) & 0xff;
	b = buf->bg_color & 0xff;

	if ((r != g) || (r != b)) {
		int x, y;
		for (y = buf->rect.y0; y < buf->rect.y1; y++) {
			unsigned char *p;
			p = buf->buf + (y - buf->rect.y0) * buf->buf_rowstride;
			for (x = buf->rect.x0; x < buf->rect.x1; x++) {
				*p++ = r;
				*p++ = g;
				*p++ = b;
			}
		}
	} else {
		int y;
		for (y = buf->rect.y0; y < buf->rect.y1; y++) {
			memset (buf->buf + (y - buf->rect.y0) * buf->buf_rowstride, r, 3 * (buf->rect.x1 - buf->rect.x0));
		}
	}
}

void
sp_canvas_render_svp_translated (SPCanvasBuf * buf, ArtSVP * svp,
	guint32 rgba, gint x, gint y)
{
	guint32 fg_color, bg_color;
	int alpha;

	sp_canvas_buf_ensure_buf (buf);

	if (buf->is_bg) {
		bg_color = buf->bg_color;
		alpha = rgba & 0xff;
		if (alpha == 0xff)
			fg_color = rgba >> 8;
		else {
			/* composite over background color */
			int bg_r, bg_g, bg_b;
			int fg_r, fg_g, fg_b;
			int tmp;

			bg_r = (bg_color >> 16) & 0xff;
			fg_r = (rgba >> 24) & 0xff;
			tmp = (fg_r - bg_r) * alpha;
			fg_r = bg_r + ((tmp + (tmp >> 8) + 0x80) >> 8);

			bg_g = (bg_color >> 8) & 0xff;
			fg_g = (rgba >> 16) & 0xff;
			tmp = (fg_g - bg_g) * alpha;
			fg_g = bg_g + ((tmp + (tmp >> 8) + 0x80) >> 8);

			bg_b = bg_color & 0xff;
			fg_b = (rgba >> 8) & 0xff;
			tmp = (fg_b - bg_b) * alpha;
			fg_b = bg_b + ((tmp + (tmp >> 8) + 0x80) >> 8);

			fg_color = (fg_r << 16) | (fg_g << 8) | fg_b;
		}
		art_rgb_svp_aa (svp,
				buf->rect.x0 - x, buf->rect.y0 - y,
				buf->rect.x1 - x, buf->rect.y1 - y,
				fg_color, bg_color,
				buf->buf, buf->buf_rowstride,
				NULL);
		buf->is_bg = 0;
		buf->is_buf = 1;
	} else {
		art_rgb_svp_alpha (svp,
				   buf->rect.x0 - x, buf->rect.y0 - y,
				   buf->rect.x1 - x, buf->rect.y1 - y,
				   rgba,
				   buf->buf, buf->buf_rowstride,
				   NULL);
	}
}

void sp_canvas_item_i2p_affine (SPCanvasItem * item, double affine[])
{
	g_return_if_fail (item != NULL);
	g_return_if_fail (affine != NULL);

	if (item->xform == NULL) {
		art_affine_identity (affine);
		return;
	}

	affine[0] = item->xform[0];
	affine[1] = item->xform[1];
	affine[2] = item->xform[2];
	affine[3] = item->xform[3];
	affine[4] = item->xform[4];
	affine[5] = item->xform[5];
}

void sp_canvas_item_i2i_affine (SPCanvasItem * from, SPCanvasItem * to, double affine[])
{
	double f2w[6], t2w[6], w2t[6];

	g_return_if_fail (from != NULL);
	g_return_if_fail (to != NULL);
	g_return_if_fail (affine != NULL);

	sp_canvas_item_i2w_affine (from, f2w);
	sp_canvas_item_i2w_affine (to, t2w);
	art_affine_invert (w2t, t2w);

	art_affine_multiply (affine, f2w, w2t);
}

void sp_canvas_item_set_i2w_affine (SPCanvasItem * item, double i2w[])
{
	double p2w[6],w2p[6],i2p[6];
	
	g_return_if_fail (item != NULL);
	g_return_if_fail (i2w != NULL);

	sp_canvas_item_i2w_affine (item->parent, p2w);
	art_affine_invert (w2p, p2w);
	art_affine_multiply (i2p, i2w, w2p);
	sp_canvas_item_affine_absolute (item, i2p);
}

void sp_canvas_item_move_to_z (SPCanvasItem * item, gint z)
{
	gint current_z;

	g_assert (item != NULL);

	current_z = sp_canvas_item_order (item);

	if (z == current_z)
		return;

	if (z > current_z)
		sp_canvas_item_raise (item, z - current_z);

	sp_canvas_item_lower (item, current_z - z);
}

gint
sp_canvas_item_compare_z (SPCanvasItem * a, SPCanvasItem * b)
{
	gint o_a, o_b;

	o_a = sp_canvas_item_order (a);
	o_b = sp_canvas_item_order (b);

	if (a > b) return -1;
	if (a < b) return 1;
	return 0;
}

