1 #define ART_RGBA_RGBA_AFFINE_C
3 /* Libart_LGPL - library of basic graphic primitives
4 * Copyright (C) 1998 Raph Levien
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
23 #include <libart_lgpl/art_misc.h>
24 #include <libart_lgpl/art_point.h>
25 #include <libart_lgpl/art_affine.h>
27 #include "art_rgb_affine_private.h"
28 #include "art_rgba_rgba_affine.h"
30 /* This module handles compositing of affine-transformed rgba images
31 over rgba pixel buffers. */
33 /* Composite the source image over the destination image, applying the
37 * gnome_print_art_rgba_rgba_affine: Affine transform source RGBA image and composite.
38 * @dst: Destination image RGB buffer.
39 * @x0: Left coordinate of destination rectangle.
40 * @y0: Top coordinate of destination rectangle.
41 * @x1: Right coordinate of destination rectangle.
42 * @y1: Bottom coordinate of destination rectangle.
43 * @dst_rowstride: Rowstride of @dst buffer.
44 * @src: Source image RGBA buffer.
45 * @src_width: Width of source image.
46 * @src_height: Height of source image.
47 * @src_rowstride: Rowstride of @src buffer.
48 * @affine: Affine transform.
49 * @level: Filter level.
50 * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
52 * Affine transform the source image stored in @src, compositing over
53 * the area of destination image @dst specified by the rectangle
54 * (@x0, @y0) - (@x1, @y1). As usual in libart, the left and top edges
55 * of this rectangle are included, and the right and bottom edges are
58 * The @alphagamma parameter specifies that the alpha compositing be
59 * done in a gamma-corrected color space. In the current
60 * implementation, it is ignored.
62 * The @level parameter specifies the speed/quality tradeoff of the
63 * image interpolation. Currently, only ART_FILTER_NEAREST is
67 gnome_print_art_rgba_rgba_affine (art_u8 *dst,
68 int x0, int y0, int x1, int y1, int dst_rowstride,
70 int src_width, int src_height, int src_rowstride,
71 const double affine[6],
73 ArtAlphaGamma *alphagamma)
75 /* Note: this is a slow implementation, and is missing all filter
76 levels other than NEAREST. It is here for clarity of presentation
77 and to establish the interface. */
80 art_u8 *dst_p, *dst_linestart;
85 art_u8 bg_r, bg_g, bg_b, bg_a, cr, cg, cb;
86 art_u8 fg_r, fg_g, fg_b;
91 art_affine_invert (inv, affine);
92 for (y = y0; y < y1; y++)
97 art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height,
99 dst_p = dst_linestart + (run_x0 - x0) * 4;
100 for (x = run_x0; x < run_x1; x++)
103 art_affine_point (&src_pt, &pt, inv);
104 src_x = floor (src_pt.x);
105 src_y = floor (src_pt.y);
106 src_p = src + (src_y * src_rowstride) + src_x * 4;
107 if (src_x >= 0 && src_x < src_width &&
108 src_y >= 0 && src_y < src_height)
128 cr = (bg_r * bg_a + 0x80) >> 8;
129 cg = (bg_g * bg_g + 0x80) >> 8;
130 cb = (bg_b * bg_b + 0x80) >> 8;
132 tmp = (src_p[0] - bg_r) * alpha;
133 fg_r = bg_r + ((tmp + (tmp >> 8) + 0x80) >> 8);
134 tmp = (src_p[1] - bg_g) * alpha;
135 fg_g = bg_g + ((tmp + (tmp >> 8) + 0x80) >> 8);
136 tmp = (src_p[2] - bg_b) * alpha;
137 fg_b = bg_b + ((tmp + (tmp >> 8) + 0x80) >> 8);
142 dst_p[3] = bg_a + (((255 - bg_a) * alpha + 0x80) >> 8);
145 } else { dst_p[0] = 255; dst_p[1] = 0; dst_p[2] = 0; dst_p[3] = 255;}
148 dst_linestart += dst_rowstride;