1 /* Libart_LGPL - library of basic graphic primitives
2 * Copyright (C) 1998 Raph Levien
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 #include "art_rgb_affine.h"
25 #include "art_point.h"
26 #include "art_affine.h"
27 #include "art_rgb_affine_private.h"
29 /* This module handles compositing of affine-transformed rgb images
30 over rgb pixel buffers. */
33 * art_rgb_affine: Affine transform source RGB image and composite.
34 * @dst: Destination image RGB buffer.
35 * @x0: Left coordinate of destination rectangle.
36 * @y0: Top coordinate of destination rectangle.
37 * @x1: Right coordinate of destination rectangle.
38 * @y1: Bottom coordinate of destination rectangle.
39 * @dst_rowstride: Rowstride of @dst buffer.
40 * @src: Source image RGB buffer.
41 * @src_width: Width of source image.
42 * @src_height: Height of source image.
43 * @src_rowstride: Rowstride of @src buffer.
44 * @affine: Affine transform.
45 * @level: Filter level.
46 * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
48 * Affine transform the source image stored in @src, compositing over
49 * the area of destination image @dst specified by the rectangle
50 * (@x0, @y0) - (@x1, @y1). As usual in libart, the left and top edges
51 * of this rectangle are included, and the right and bottom edges are
54 * The @alphagamma parameter specifies that the alpha compositing be done
55 * in a gamma-corrected color space. Since the source image is opaque RGB,
56 * this argument only affects the edges. In the current implementation,
59 * The @level parameter specifies the speed/quality tradeoff of the
60 * image interpolation. Currently, only ART_FILTER_NEAREST is
64 art_rgb_affine (art_u8 *dst, int x0, int y0, int x1, int y1, int dst_rowstride,
66 int src_width, int src_height, int src_rowstride,
67 const double affine[6],
69 ArtAlphaGamma *alphagamma)
71 /* Note: this is a slow implementation, and is missing all filter
72 levels other than NEAREST. It is here for clarity of presentation
73 and to establish the interface. */
76 art_u8 *dst_p, *dst_linestart;
83 art_affine_invert (inv, affine);
84 for (y = y0; y < y1; y++)
89 art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height,
91 dst_p = dst_linestart + (run_x0 - x0) * 3;
92 for (x = run_x0; x < run_x1; x++)
95 art_affine_point (&src_pt, &pt, inv);
96 src_x = floor (src_pt.x);
97 src_y = floor (src_pt.y);
98 src_p = src + (src_y * src_rowstride) + src_x * 3;
104 dst_linestart += dst_rowstride;