255 lines
6.3 KiB
C
255 lines
6.3 KiB
C
/*
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*
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* Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
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* 2005 Lars Knoll & Zack Rusin, Trolltech
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name of Keith Packard not be used in
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* advertising or publicity pertaining to distribution of the software without
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* specific, written prior permission. Keith Packard makes no
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* representations about the suitability of this software for any purpose. It
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* is provided "as is" without express or implied warranty.
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*
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
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* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
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* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include "pixman-private.h"
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void
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_pixman_gradient_walker_init (pixman_gradient_walker_t *walker,
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gradient_t * gradient,
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unsigned int spread)
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{
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walker->num_stops = gradient->n_stops;
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walker->stops = gradient->stops;
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walker->left_x = 0;
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walker->right_x = 0x10000;
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walker->stepper = 0;
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walker->left_ag = 0;
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walker->left_rb = 0;
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walker->right_ag = 0;
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walker->right_rb = 0;
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walker->spread = spread;
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walker->need_reset = TRUE;
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}
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void
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_pixman_gradient_walker_reset (pixman_gradient_walker_t *walker,
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pixman_fixed_32_32_t pos)
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{
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int32_t x, left_x, right_x;
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pixman_color_t *left_c, *right_c;
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int n, count = walker->num_stops;
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pixman_gradient_stop_t * stops = walker->stops;
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static const pixman_color_t transparent_black = { 0, 0, 0, 0 };
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switch (walker->spread)
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{
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case PIXMAN_REPEAT_NORMAL:
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x = (int32_t)pos & 0xFFFF;
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for (n = 0; n < count; n++)
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if (x < stops[n].x)
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break;
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if (n == 0)
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{
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left_x = stops[count - 1].x - 0x10000;
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left_c = &stops[count - 1].color;
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}
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else
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{
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left_x = stops[n - 1].x;
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left_c = &stops[n - 1].color;
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}
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if (n == count)
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{
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right_x = stops[0].x + 0x10000;
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right_c = &stops[0].color;
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}
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else
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{
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right_x = stops[n].x;
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right_c = &stops[n].color;
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}
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left_x += (pos - x);
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right_x += (pos - x);
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break;
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case PIXMAN_REPEAT_PAD:
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for (n = 0; n < count; n++)
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if (pos < stops[n].x)
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break;
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if (n == 0)
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{
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left_x = INT32_MIN;
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left_c = &stops[0].color;
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}
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else
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{
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left_x = stops[n - 1].x;
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left_c = &stops[n - 1].color;
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}
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if (n == count)
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{
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right_x = INT32_MAX;
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right_c = &stops[n - 1].color;
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}
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else
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{
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right_x = stops[n].x;
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right_c = &stops[n].color;
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}
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break;
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case PIXMAN_REPEAT_REFLECT:
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x = (int32_t)pos & 0xFFFF;
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if ((int32_t)pos & 0x10000)
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x = 0x10000 - x;
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for (n = 0; n < count; n++)
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if (x < stops[n].x)
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break;
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if (n == 0)
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{
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left_x = -stops[0].x;
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left_c = &stops[0].color;
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}
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else
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{
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left_x = stops[n - 1].x;
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left_c = &stops[n - 1].color;
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}
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if (n == count)
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{
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right_x = 0x20000 - stops[n - 1].x;
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right_c = &stops[n - 1].color;
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}
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else
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{
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right_x = stops[n].x;
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right_c = &stops[n].color;
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}
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if ((int32_t)pos & 0x10000)
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{
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pixman_color_t *tmp_c;
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int32_t tmp_x;
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tmp_x = 0x10000 - right_x;
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right_x = 0x10000 - left_x;
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left_x = tmp_x;
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tmp_c = right_c;
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right_c = left_c;
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left_c = tmp_c;
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x = 0x10000 - x;
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}
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left_x += (pos - x);
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right_x += (pos - x);
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break;
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default: /* REPEAT_NONE */
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for (n = 0; n < count; n++)
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if (pos < stops[n].x)
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break;
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if (n == 0)
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{
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left_x = INT32_MIN;
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right_x = stops[0].x;
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left_c = right_c = (pixman_color_t*) &transparent_black;
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}
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else if (n == count)
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{
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left_x = stops[n - 1].x;
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right_x = INT32_MAX;
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left_c = right_c = (pixman_color_t*) &transparent_black;
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}
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else
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{
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left_x = stops[n - 1].x;
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right_x = stops[n].x;
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left_c = &stops[n - 1].color;
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right_c = &stops[n].color;
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}
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}
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walker->left_x = left_x;
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walker->right_x = right_x;
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walker->left_ag = ((left_c->alpha >> 8) << 16) | (left_c->green >> 8);
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walker->left_rb = ((left_c->red & 0xff00) << 8) | (left_c->blue >> 8);
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walker->right_ag = ((right_c->alpha >> 8) << 16) | (right_c->green >> 8);
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walker->right_rb = ((right_c->red & 0xff00) << 8) | (right_c->blue >> 8);
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if (walker->left_x == walker->right_x ||
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( walker->left_ag == walker->right_ag &&
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walker->left_rb == walker->right_rb ) )
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{
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walker->stepper = 0;
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}
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else
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{
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int32_t width = right_x - left_x;
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walker->stepper = ((1 << 24) + width / 2) / width;
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}
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walker->need_reset = FALSE;
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}
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#define PIXMAN_GRADIENT_WALKER_NEED_RESET(w, x) \
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( (w)->need_reset || (x) < (w)->left_x || (x) >= (w)->right_x)
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/* the following assumes that PIXMAN_GRADIENT_WALKER_NEED_RESET(w,x) is FALSE */
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uint32_t
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_pixman_gradient_walker_pixel (pixman_gradient_walker_t *walker,
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pixman_fixed_32_32_t x)
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{
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int dist, idist;
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uint32_t t1, t2, a, color;
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if (PIXMAN_GRADIENT_WALKER_NEED_RESET (walker, x))
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_pixman_gradient_walker_reset (walker, x);
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dist = ((int)(x - walker->left_x) * walker->stepper) >> 16;
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idist = 256 - dist;
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/* combined INTERPOLATE and premultiply */
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t1 = walker->left_rb * idist + walker->right_rb * dist;
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t1 = (t1 >> 8) & 0xff00ff;
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t2 = walker->left_ag * idist + walker->right_ag * dist;
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t2 &= 0xff00ff00;
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color = t2 & 0xff000000;
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a = t2 >> 24;
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t1 = t1 * a + 0x800080;
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t1 = (t1 + ((t1 >> 8) & 0xff00ff)) >> 8;
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t2 = (t2 >> 8) * a + 0x800080;
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t2 = (t2 + ((t2 >> 8) & 0xff00ff));
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return (color | (t1 & 0xff00ff) | (t2 & 0xff00));
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}
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