1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/* 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_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)
{
gint 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, gint n)
{
gint i;
guint 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, gint alpha, gint n)
{
gint i;
gint 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);
}
}
|
