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/*
*
* Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
* 2005 Lars Knoll & Zack Rusin, Trolltech
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of Keith Packard not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. Keith Packard makes no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "pixman-private.h"
void
_pixman_gradient_walker_init (pixman_gradient_walker_t *walker,
gradient_t * gradient,
pixman_repeat_t repeat)
{
walker->num_stops = gradient->n_stops;
walker->stops = gradient->stops;
walker->left_x = 0;
walker->right_x = 0x10000;
walker->stepper = 0;
walker->left_ag = 0;
walker->left_rb = 0;
walker->right_ag = 0;
walker->right_rb = 0;
walker->repeat = repeat;
walker->need_reset = TRUE;
}
static void
gradient_walker_reset (pixman_gradient_walker_t *walker,
pixman_fixed_48_16_t pos)
{
int32_t x, left_x, right_x;
pixman_color_t *left_c, *right_c;
int n, count = walker->num_stops;
pixman_gradient_stop_t *stops = walker->stops;
if (walker->repeat == PIXMAN_REPEAT_NORMAL)
{
x = (int32_t)pos & 0xffff;
}
else if (walker->repeat == PIXMAN_REPEAT_REFLECT)
{
x = (int32_t)pos & 0xffff;
if ((int32_t)pos & 0x10000)
x = 0x10000 - x;
}
else
{
x = pos;
}
for (n = 0; n < count; n++)
{
if (x < stops[n].x)
break;
}
left_x = stops[n - 1].x;
left_c = &stops[n - 1].color;
right_x = stops[n].x;
right_c = &stops[n].color;
if (walker->repeat == PIXMAN_REPEAT_NORMAL)
{
left_x += (pos - x);
right_x += (pos - x);
}
else if (walker->repeat == PIXMAN_REPEAT_REFLECT)
{
if ((int32_t)pos & 0x10000)
{
pixman_color_t *tmp_c;
int32_t tmp_x;
tmp_x = 0x10000 - right_x;
right_x = 0x10000 - left_x;
left_x = tmp_x;
tmp_c = right_c;
right_c = left_c;
left_c = tmp_c;
x = 0x10000 - x;
}
left_x += (pos - x);
right_x += (pos - x);
}
walker->left_x = left_x;
walker->right_x = right_x;
walker->left_ag = ((left_c->alpha >> 8) << 16) | (left_c->green >> 8);
walker->left_rb = ((left_c->red & 0xff00) << 8) | (left_c->blue >> 8);
walker->right_ag = ((right_c->alpha >> 8) << 16) | (right_c->green >> 8);
walker->right_rb = ((right_c->red & 0xff00) << 8) | (right_c->blue >> 8);
if (walker->left_x == walker->right_x ||
(walker->left_ag == walker->right_ag &&
walker->left_rb == walker->right_rb))
{
walker->stepper = 0;
}
else
{
int32_t width = right_x - left_x;
walker->stepper = ((1 << 24) + width / 2) / width;
}
walker->need_reset = FALSE;
}
uint32_t
_pixman_gradient_walker_pixel (pixman_gradient_walker_t *walker,
pixman_fixed_48_16_t x)
{
int dist, idist;
uint32_t t1, t2, a, color;
if (walker->need_reset || x < walker->left_x || x >= walker->right_x)
gradient_walker_reset (walker, x);
dist = ((int)(x - walker->left_x) * walker->stepper) >> 16;
idist = 256 - dist;
/* combined INTERPOLATE and premultiply */
t1 = walker->left_rb * idist + walker->right_rb * dist;
t1 = (t1 >> 8) & 0xff00ff;
t2 = walker->left_ag * idist + walker->right_ag * dist;
t2 &= 0xff00ff00;
color = t2 & 0xff000000;
a = t2 >> 24;
t1 = t1 * a + 0x800080;
t1 = (t1 + ((t1 >> 8) & 0xff00ff)) >> 8;
t2 = (t2 >> 8) * a + 0x800080;
t2 = (t2 + ((t2 >> 8) & 0xff00ff));
return (color | (t1 & 0xff00ff) | (t2 & 0xff00));
}
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