/*
* Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation
* All rights reserved.
*
* This file is part of the Gnome Library.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* published by the Free Software Foundation; either the
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* License along with the Gnome Library; see the file COPYING.LIB. If not,
*/
/*
@NOTATION@
*/
/* Miscellaneous utility functions for the GnomeCanvas widget
*
* GnomeCanvas is basically a port of the Tk toolkit's most excellent canvas
* widget. Tk is copyrighted by the Regents of the University of California,
* Sun Microsystems, and other parties.
*
*
* Author: Federico Mena <federico@nuclecu.unam.mx>
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
/* needed for M_PI_2 under 'gcc -ansi -predantic' on GNU/Linux */
#ifndef _BSD_SOURCE
# define _BSD_SOURCE 1
#endif
#include <sys/types.h>
#include <math.h>
#include "gnome-canvas.h"
#include "gnome-canvas-util.h"
/* Here are some helper functions for aa rendering: */
/**
* gnome_canvas_item_reset_bounds:
* @item: A canvas item
*
* Resets the bounding box of a canvas item to an empty rectangle.
**/
void
gnome_canvas_item_reset_bounds (GnomeCanvasItem *item)
{
item->x1 = 0.0;
item->y1 = 0.0;
item->x2 = 0.0;
item->y2 = 0.0;
}
/**
* gnome_canvas_update_bbox:
* @item: the canvas item needing update
* @x1: Left coordinate of the new bounding box
* @y1: Top coordinate of the new bounding box
* @x2: Right coordinate of the new bounding box
* @y2: Bottom coordinate of the new bounding box
*
* Sets the bbox to the new value, requesting full repaint.
**/
void
gnome_canvas_update_bbox (GnomeCanvasItem *item,
gint x1,
gint y1,
gint x2,
gint y2)
{
gnome_canvas_request_redraw (
item->canvas, item->x1, item->y1, item->x2, item->y2);
item->x1 = x1;
item->y1 = y1;
item->x2 = x2;
item->y2 = y2;
gnome_canvas_request_redraw (
item->canvas, item->x1, item->y1, item->x2, item->y2);
}
/**
* gnome_canvas_cairo_create_scratch:
*
* Create a scratch #cairo_t. This is useful for measuring purposes or
* calling functions like cairo_in_fill().
*
* Returns: A new cairo_t. Destroy with cairo_destroy() after use.
**/
cairo_t *
gnome_canvas_cairo_create_scratch (void)
{
cairo_surface_t *surface;
cairo_t *cr;
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 0, 0);
cr = cairo_create (surface);
cairo_surface_destroy (surface);
return cr;
}
/**
* gnome_canvas_matrix_transform_rect:
* @matrix: a cairo matrix
* @x1: x coordinate of top left position of rectangle (in-out)
* @y1: y coordinate of top left position of rectangle (in-out)
* @x2: x coordinate of bottom right position of rectangle (in-out)
* @y2: y coordinate of bottom right position of rectangle (in-out)
*
* Computes the smallest rectangle containing the whole area of the given
* rectangle after applying the transformation given in @matrix.
**/
void
gnome_canvas_matrix_transform_rect (const cairo_matrix_t *matrix,
gdouble *x1,
gdouble *y1,
gdouble *x2,
gdouble *y2)
{
gdouble maxx, maxy, minx, miny;
gdouble tmpx, tmpy;
tmpx = *x1;
tmpy = *y1;
cairo_matrix_transform_point (matrix, &tmpx, &tmpy);
minx = maxx = tmpx;
miny = maxy = tmpy;
tmpx = *x2;
tmpy = *y1;
cairo_matrix_transform_point (matrix, &tmpx, &tmpy);
minx = MIN (minx, tmpx);
maxx = MAX (maxx, tmpx);
miny = MIN (miny, tmpy);
maxy = MAX (maxy, tmpy);
tmpx = *x2;
tmpy = *y2;
cairo_matrix_transform_point (matrix, &tmpx, &tmpy);
minx = MIN (minx, tmpx);
maxx = MAX (maxx, tmpx);
miny = MIN (miny, tmpy);
maxy = MAX (maxy, tmpy);
tmpx = *x1;
tmpy = *y2;
cairo_matrix_transform_point (matrix, &tmpx, &tmpy);
minx = MIN (minx, tmpx);
maxx = MAX (maxx, tmpx);
miny = MIN (miny, tmpy);
maxy = MAX (maxy, tmpy);
*x1 = minx;
*x2 = maxx;
*y1 = miny;
*y2 = maxy;
}
