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/* Libart_LGPL - library of basic graphic primitives
* Copyright (C) 1998 Raph Levien
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include "art_rect.h"
#include <math.h>
#ifndef MAX
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#endif /* MAX */
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif /* MIN */
/* rectangle primitives stolen from gzilla */
/**
* art_irect_intersection: Find intersection of two integer rectangles.
* @dest: Where the result is stored.
* @src1: A source rectangle.
* @src2: Another source rectangle.
*
* Finds the intersection of @src1 and @src2.
**/
void
art_irect_intersect (ArtIRect *dest, const ArtIRect *src1, const ArtIRect *src2) {
dest->x0 = MAX (src1->x0, src2->x0);
dest->y0 = MAX (src1->y0, src2->y0);
dest->x1 = MIN (src1->x1, src2->x1);
dest->y1 = MIN (src1->y1, src2->y1);
}
/**
* art_irect_empty: Determine whether integer rectangle is empty.
* @src: The source rectangle.
*
* Return value: TRUE if @src is an empty rectangle, FALSE otherwise.
**/
gint
art_irect_empty (const ArtIRect *src) {
return (src->x1 <= src->x0 || src->y1 <= src->y0);
}
/**
* art_drect_copy: Make a copy of a rectangle.
* @dest: Where the copy is stored.
* @src: The source rectangle.
*
* Copies the rectangle.
**/
void
art_drect_copy (ArtDRect *dest, const ArtDRect *src) {
dest->x0 = src->x0;
dest->y0 = src->y0;
dest->x1 = src->x1;
dest->y1 = src->y1;
}
/**
* art_drect_union: Find union of two rectangles.
* @dest: Where the result is stored.
* @src1: A source rectangle.
* @src2: Another source rectangle.
*
* Finds the smallest rectangle that includes @src1 and @src2.
**/
void
art_drect_union (ArtDRect *dest, const ArtDRect *src1, const ArtDRect *src2) {
if (art_drect_empty (src1)) {
art_drect_copy (dest, src2);
} else if (art_drect_empty (src2)) {
art_drect_copy (dest, src1);
} else {
dest->x0 = MIN (src1->x0, src2->x0);
dest->y0 = MIN (src1->y0, src2->y0);
dest->x1 = MAX (src1->x1, src2->x1);
dest->y1 = MAX (src1->y1, src2->y1);
}
}
/**
* art_irect_empty: Determine whether rectangle is empty.
* @src: The source rectangle.
*
* Return value: TRUE if @src is an empty rectangle, FALSE otherwise.
**/
gint
art_drect_empty (const ArtDRect *src) {
return (src->x1 <= src->x0 || src->y1 <= src->y0);
}
/**
* art_drect_affine_transform: Affine transform rectangle.
* @dst: Where to store the result.
* @src: The source rectangle.
* @matrix: The affine transformation.
*
* Find the smallest rectangle enclosing the affine transformed @src.
* The result is exactly the affine transformation of @src when
* @matrix specifies a rectilinear affine transformation, otherwise it
* is a conservative approximation.
**/
void
art_drect_affine_transform (ArtDRect *dst,
const ArtDRect *src,
const gdouble matrix[6])
{
gdouble x00, y00, x10, y10;
gdouble x01, y01, x11, y11;
x00 = src->x0 * matrix[0] + src->y0 * matrix[2] + matrix[4];
y00 = src->x0 * matrix[1] + src->y0 * matrix[3] + matrix[5];
x10 = src->x1 * matrix[0] + src->y0 * matrix[2] + matrix[4];
y10 = src->x1 * matrix[1] + src->y0 * matrix[3] + matrix[5];
x01 = src->x0 * matrix[0] + src->y1 * matrix[2] + matrix[4];
y01 = src->x0 * matrix[1] + src->y1 * matrix[3] + matrix[5];
x11 = src->x1 * matrix[0] + src->y1 * matrix[2] + matrix[4];
y11 = src->x1 * matrix[1] + src->y1 * matrix[3] + matrix[5];
dst->x0 = MIN (MIN (x00, x10), MIN (x01, x11));
dst->y0 = MIN (MIN (y00, y10), MIN (y01, y11));
dst->x1 = MAX (MAX (x00, x10), MAX (x01, x11));
dst->y1 = MAX (MAX (y00, y10), MAX (y01, y11));
}
/**
* art_drect_to_irect: Convert rectangle to integer rectangle.
* @dst: Where to store resulting integer rectangle.
* @src: The source rectangle.
*
* Find the smallest integer rectangle that encloses @src.
**/
void
art_drect_to_irect (ArtIRect *dst, ArtDRect *src)
{
dst->x0 = floor (src->x0);
dst->y0 = floor (src->y0);
dst->x1 = ceil (src->x1);
dst->y1 = ceil (src->y1);
}
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