/*
* art_rgba.c: Functions for manipulating RGBA pixel data.
*
* Libart_LGPL - library of basic graphic primitives
* Copyright (C) 2000 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_rgba.h"
#define ART_OPTIMIZE_SPACE
#ifndef ART_OPTIMIZE_SPACE
#include "art_rgba_table.c"
#endif
/**
* art_rgba_rgba_composite: Composite RGBA image over RGBA buffer.
* @dst: Destination RGBA buffer.
* @src: Source RGBA buffer.
* @n: Number of RGBA pixels to composite.
*
* Composites the RGBA pixels in @dst over the @src buffer.
**/
void
art_rgba_rgba_composite (art_u8 *dst, const art_u8 *src, int n)
{
int i;
#ifdef WORDS_BIGENDIAN
art_u32 src_rgba, dst_rgba;
#else
art_u32 src_abgr, dst_abgr;
#endif
art_u8 src_alpha, dst_alpha;
for (i = 0; i < n; i++)
{
#ifdef WORDS_BIGENDIAN
src_rgba = ((art_u32 *)src)[i];
src_alpha = src_rgba & 0xff;
#else
src_abgr = ((art_u32 *)src)[i];
src_alpha = (src_abgr >> 24) & 0xff;
#endif
if (src_alpha)
{
if (src_alpha == 0xff ||
(
#ifdef WORDS_BIGENDIAN
dst_rgba = ((art_u32 *)dst)[i],
dst_alpha = dst_rgba & 0xff,
#else
dst_abgr = ((art_u32 *)dst)[i],
dst_alpha = (dst_abgr >> 24),
#endif
dst_alpha == 0))
#ifdef WORDS_BIGENDIAN
((art_u32 *)dst)[i] = src_rgba;
#else
((art_u32 *)dst)[i] = src_abgr;
#endif
else
{
int r, g, b, a;
int src_r, src_g, src_b;
int dst_r, dst_g, dst_b;
int tmp;
int c;
#ifdef ART_OPTIMIZE_SPACE
tmp = (255 - src_alpha) * (255 - dst_alpha) + 0x80;
a = 255 - ((tmp + (tmp >> 8)) >> 8);
c = ((src_alpha << 16) + (a >> 1)) / a;
#else
tmp = art_rgba_composite_table[(src_alpha << 8) + dst_alpha];
c = tmp & 0x1ffff;
a = tmp >> 24;
#endif
#ifdef WORDS_BIGENDIAN
src_r = (src_rgba >> 24) & 0xff;
src_g = (src_rgba >> 16) & 0xff;
src_b = (src_rgba >> 8) & 0xff;
dst_r = (dst_rgba >> 24) & 0xff;
dst_g = (dst_rgba >> 16) & 0xff;
dst_b = (dst_rgba >> 8) & 0xff;
#else
src_r = src_abgr & 0xff;
src_g = (src_abgr >> 8) & 0xff;
src_b = (src_abgr >> 16) & 0xff;
dst_r = dst_abgr & 0xff;
dst_g = (dst_abgr >> 8) & 0xff;
dst_b = (dst_abgr >> 16) & 0xff;
#endif
r = dst_r + (((src_r - dst_r) * c + 0x8000) >> 16);
g = dst_g + (((src_g - dst_g) * c + 0x8000) >> 16);
b = dst_b + (((src_b - dst_b) * c + 0x8000) >> 16);
#ifdef WORDS_BIGENDIAN
((art_u32 *)dst)[i] = (r << 24) | (g << 16) | (b << 8) | a;
#else
((art_u32 *)dst)[i] = (a << 24) | (b << 16) | (g << 8) | r;
#endif
}
}
#if 0
/* it's not clear to me this optimization really wins */
else
{
/* skip over run of transparent pixels */
for (; i < n - 1; i++)
{
#ifdef WORDS_BIGENDIAN
src_rgba = ((art_u32 *)src)[i + 1];
if (src_rgba & 0xff)
break;
#else
src_abgr = ((art_u32 *)src)[i + 1];
if (src_abgr & 0xff000000)
break;
#endif
}
}
#endif
}
}
/**
* art_rgba_fill_run: fill an RGBA 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, solid
* alpha. Thus, locations @buf (inclusive) through @buf + 4 * @n
* (exclusive) are written.
**/
void
art_rgba_fill_run (art_u8 *buf, art_u8 r, art_u8 g, art_u8 b, int n)
{
int i;
#ifdef WORDS_BIGENDIAN
art_u32 src_rgba;
#else
art_u32 src_abgr;
#endif
#ifdef WORDS_BIGENDIAN
src_rgba = (r << 24) | (g << 16) | (b << 8) | 255;
#else
src_abgr = (255 << 24) | (b << 16) | (g << 8) | r;
#endif
for (i = 0; i < n; i++)
{
#ifdef WORDS_BIGENDIAN
((art_u32 *)buf)[i] = src_rgba;
#else
((art_u32 *)buf)[i] = src_abgr;
#endif
}
}
/**
* art_rgba_run_alpha: Render semitransparent color over RGBA buffer.
* @buf: Buffer for rendering.
* @r: Red, range 0..255.
* @g: Green, range 0..255.
* @b: Blue, range 0..255.
* @alpha: Alpha, range 0..255.
* @n: Number of RGB triples to render.
*
* Renders a sequential run of solid (@r, @g, @b) color over @buf with
* opacity @alpha. Note that the range of @alpha is 0..255, in contrast
* to art_rgb_run_alpha, which has a range of 0..256.
**/
void
art_rgba_run_alpha (art_u8 *buf, art_u8 r, art_u8 g, art_u8 b, int alpha, int n)
{
int i;
#ifdef WORDS_BIGENDIAN
art_u32 src_rgba, dst_rgba;
#else
art_u32 src_abgr, dst_abgr;
#endif
art_u8 dst_alpha;
int a;
int dst_r, dst_g, dst_b;
int tmp;
int c;
#ifdef WORDS_BIGENDIAN
src_rgba = (r << 24) | (g << 16) | (b << 8) | alpha;
#else
src_abgr = (alpha << 24) | (b << 16) | (g << 8) | r;
#endif
for (i = 0; i < n; i++)
{
#ifdef WORDS_BIGENDIAN
dst_rgba = ((art_u32 *)buf)[i];
dst_alpha = dst_rgba & 0xff;
#else
dst_abgr = ((art_u32 *)buf)[i];
dst_alpha = (dst_abgr >> 24) & 0xff;
#endif
if (dst_alpha)
{
#ifdef ART_OPTIMIZE_SPACE
tmp = (255 - alpha) * (255 - dst_alpha) + 0x80;
a = 255 - ((tmp + (tmp >> 8)) >> 8);
c = ((alpha << 16) + (a >> 1)) / a;
#else
tmp = art_rgba_composite_table[(alpha << 8) + dst_alpha];
c = tmp & 0x1ffff;
a = tmp >> 24;
#endif
#ifdef WORDS_BIGENDIAN
dst_r = (dst_rgba >> 24) & 0xff;
dst_g = (dst_rgba >> 16) & 0xff;
dst_b = (dst_rgba >> 8) & 0xff;
#else
dst_r = dst_abgr & 0xff;
dst_g = (dst_abgr >> 8) & 0xff;
dst_b = (dst_abgr >> 16) & 0xff;
#endif
dst_r += (((r - dst_r) * c + 0x8000) >> 16);
dst_g += (((g - dst_g) * c + 0x8000) >> 16);
dst_b += (((b - dst_b) * c + 0x8000) >> 16);
#ifdef WORDS_BIGENDIAN
((art_u32 *)buf)[i] = (dst_r << 24) | (dst_g << 16) | (dst_b << 8) | a;
#else
((art_u32 *)buf)[i] = (a << 24) | (dst_b << 16) | (dst_g << 8) | dst_r;
#endif
}
else
{
#ifdef WORDS_BIGENDIAN
((art_u32 *)buf)[i] = src_rgba;
#else
((art_u32 *)buf)[i] = src_abgr;
#endif
}
}
}
