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Diffstat (limited to 'src/libart_lgpl/art_rgb.c')
| -rw-r--r-- | src/libart_lgpl/art_rgb.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/libart_lgpl/art_rgb.c b/src/libart_lgpl/art_rgb.c new file mode 100644 index 0000000..c007775 --- /dev/null +++ b/src/libart_lgpl/art_rgb.c @@ -0,0 +1,174 @@ +/* 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 3 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, see <http://www.gnu.org/licenses/>. + * Boston, MA 02111-1307, USA. + */ + +#include "config.h" +#include "art_rgb.h" + +#include <string.h> /* for memset */ + +/* Basic operators for manipulating 24-bit packed RGB buffers. */ + +#define COLOR_RUN_COMPLEX + +#ifdef COLOR_RUN_SIMPLE +/* This is really slow. Is there any way we might speed it up? + Two ideas: + + First, maybe we should be working at 32-bit alignment. Then, + this can be a simple loop over word stores. + + Second, we can keep working at 24-bit alignment, but have some + intelligence about storing. For example, we can iterate over + 4-pixel chunks (aligned at 4 pixels), with an inner loop + something like: + + *buf++ = v1; + *buf++ = v2; + *buf++ = v3; + + One source of extra complexity is the need to make sure linebuf is + aligned to a 32-bit boundary. + + This second alternative has some complexity to it, but is + appealing because it really minimizes the memory bandwidth. */ +void +art_rgb_fill_run (art_u8 *buf, art_u8 r, art_u8 g, art_u8 b, gint n) +{ + int i; + + if (r == g && g == b) + { + memset (buf, g, n + n + n); + } + else + { + for (i = 0; i < n; i++) + { + *buf++ = r; + *buf++ = g; + *buf++ = b; + } + } +} +#endif + +#ifdef COLOR_RUN_COMPLEX +/* This implements the second of the two ideas above. The test results + are _very_ encouraging - it seems the speed is within 10% of + memset, which is quite good! */ +/** + * art_rgb_fill_run: fill a buffer a solid RGB color. + * @buf: Buffer to fill. + * @r: Red, range 0..255. + * @g: Green, range 0..255. + * @b: Blue, range 0..255. + * @n: Number of RGB triples to fill. + * + * Fills a buffer with @n copies of the (@r, @g, @b) triple. Thus, + * locations @buf (inclusive) through @buf + 3 * @n (exclusive) are + * written. + * + * The implementation of this routine is very highly optimized. + **/ +void +art_rgb_fill_run (art_u8 *buf, art_u8 r, art_u8 g, art_u8 b, int n) +{ + int i; + unsigned int v1, v2, v3; + + if (r == g && g == b) + { + memset (buf, g, n + n + n); + } + else + { + if (n < 8) + { + for (i = 0; i < n; i++) + { + *buf++ = r; + *buf++ = g; + *buf++ = b; + } + } else { + /* handle prefix up to byte alignment */ + /* I'm worried about this cast on sizeof(long) != sizeof(uchar *) + architectures, but it _should_ work. */ + for (i = 0; ((unsigned long)buf) & 3; i++) + { + *buf++ = r; + *buf++ = g; + *buf++ = b; + } +#ifndef WORDS_BIGENDIAN + v1 = r | (g << 8) | (b << 16) | (r << 24); + v3 = (v1 << 8) | b; + v2 = (v3 << 8) | g; +#else + v1 = (r << 24) | (g << 16) | (b << 8) | r; + v2 = (v1 << 8) | g; + v3 = (v2 << 8) | b; +#endif + for (; i < n - 3; i += 4) + { + ((art_u32 *)buf)[0] = v1; + ((art_u32 *)buf)[1] = v2; + ((art_u32 *)buf)[2] = v3; + buf += 12; + } + /* handle postfix */ + for (; i < n; i++) + { + *buf++ = r; + *buf++ = g; + *buf++ = b; + } + } + } +} +#endif + +/** + * art_rgb_run_alpha: Render semitransparent color over RGB buffer. + * @buf: Buffer for rendering. + * @r: Red, range 0..255. + * @g: Green, range 0..255. + * @b: Blue, range 0..255. + * @alpha: Alpha, range 0..256. + * @n: Number of RGB triples to render. + * + * Renders a sequential run of solid (@r, @g, @b) color over @buf with + * opacity @alpha. + **/ +void +art_rgb_run_alpha (art_u8 *buf, art_u8 r, art_u8 g, art_u8 b, int alpha, int n) +{ + int i; + int v; + + for (i = 0; i < n; i++) + { + v = *buf; + *buf++ = v + (((r - v) * alpha + 0x80) >> 8); + v = *buf; + *buf++ = v + (((g - v) * alpha + 0x80) >> 8); + v = *buf; + *buf++ = v + (((b - v) * alpha + 0x80) >> 8); + } +} + |