393 lines
9.3 KiB
C
393 lines
9.3 KiB
C
/*
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* Copyright © 2004 Keith Packard
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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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* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS 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 <stdio.h>
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#include "pixman-private.h"
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/*
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* Compute the smallest value greater than or equal to y which is on a
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* grid row.
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*/
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PIXMAN_EXPORT pixman_fixed_t
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pixman_sample_ceil_y (pixman_fixed_t y, int n)
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{
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pixman_fixed_t f = pixman_fixed_frac (y);
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pixman_fixed_t i = pixman_fixed_floor (y);
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f = DIV (f - Y_FRAC_FIRST (n) + (STEP_Y_SMALL (n) - pixman_fixed_e), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +
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Y_FRAC_FIRST (n);
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if (f > Y_FRAC_LAST (n))
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{
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if (pixman_fixed_to_int (i) == 0x7fff)
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{
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f = 0xffff; /* saturate */
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}
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else
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{
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f = Y_FRAC_FIRST (n);
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i += pixman_fixed_1;
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}
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}
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return (i | f);
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}
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/*
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* Compute the largest value strictly less than y which is on a
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* grid row.
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*/
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PIXMAN_EXPORT pixman_fixed_t
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pixman_sample_floor_y (pixman_fixed_t y,
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int n)
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{
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pixman_fixed_t f = pixman_fixed_frac (y);
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pixman_fixed_t i = pixman_fixed_floor (y);
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f = DIV (f - pixman_fixed_e - Y_FRAC_FIRST (n), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +
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Y_FRAC_FIRST (n);
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if (f < Y_FRAC_FIRST (n))
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{
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if (pixman_fixed_to_int (i) == 0x8000)
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{
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f = 0; /* saturate */
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}
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else
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{
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f = Y_FRAC_LAST (n);
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i -= pixman_fixed_1;
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}
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}
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return (i | f);
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}
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/*
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* Step an edge by any amount (including negative values)
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*/
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PIXMAN_EXPORT void
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pixman_edge_step (pixman_edge_t *e,
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int n)
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{
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pixman_fixed_48_16_t ne;
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e->x += n * e->stepx;
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ne = e->e + n * (pixman_fixed_48_16_t) e->dx;
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if (n >= 0)
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{
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if (ne > 0)
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{
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int nx = (ne + e->dy - 1) / e->dy;
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e->e = ne - nx * (pixman_fixed_48_16_t) e->dy;
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e->x += nx * e->signdx;
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}
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}
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else
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{
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if (ne <= -e->dy)
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{
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int nx = (-ne) / e->dy;
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e->e = ne + nx * (pixman_fixed_48_16_t) e->dy;
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e->x -= nx * e->signdx;
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}
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}
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}
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/*
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* A private routine to initialize the multi-step
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* elements of an edge structure
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*/
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static void
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_pixman_edge_multi_init (pixman_edge_t * e,
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int n,
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pixman_fixed_t *stepx_p,
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pixman_fixed_t *dx_p)
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{
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pixman_fixed_t stepx;
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pixman_fixed_48_16_t ne;
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ne = n * (pixman_fixed_48_16_t) e->dx;
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stepx = n * e->stepx;
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if (ne > 0)
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{
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int nx = ne / e->dy;
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ne -= nx * e->dy;
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stepx += nx * e->signdx;
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}
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*dx_p = ne;
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*stepx_p = stepx;
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}
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/*
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* Initialize one edge structure given the line endpoints and a
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* starting y value
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*/
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PIXMAN_EXPORT void
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pixman_edge_init (pixman_edge_t *e,
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int n,
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pixman_fixed_t y_start,
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pixman_fixed_t x_top,
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pixman_fixed_t y_top,
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pixman_fixed_t x_bot,
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pixman_fixed_t y_bot)
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{
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pixman_fixed_t dx, dy;
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e->x = x_top;
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e->e = 0;
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dx = x_bot - x_top;
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dy = y_bot - y_top;
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e->dy = dy;
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e->dx = 0;
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if (dy)
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{
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if (dx >= 0)
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{
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e->signdx = 1;
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e->stepx = dx / dy;
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e->dx = dx % dy;
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e->e = -dy;
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}
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else
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{
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e->signdx = -1;
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e->stepx = -(-dx / dy);
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e->dx = -dx % dy;
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e->e = 0;
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}
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_pixman_edge_multi_init (e, STEP_Y_SMALL (n),
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&e->stepx_small, &e->dx_small);
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_pixman_edge_multi_init (e, STEP_Y_BIG (n),
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&e->stepx_big, &e->dx_big);
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}
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pixman_edge_step (e, y_start - y_top);
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}
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/*
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* Initialize one edge structure given a line, starting y value
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* and a pixel offset for the line
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*/
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PIXMAN_EXPORT void
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pixman_line_fixed_edge_init (pixman_edge_t * e,
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int n,
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pixman_fixed_t y,
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const pixman_line_fixed_t *line,
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int x_off,
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int y_off)
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{
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pixman_fixed_t x_off_fixed = pixman_int_to_fixed (x_off);
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pixman_fixed_t y_off_fixed = pixman_int_to_fixed (y_off);
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const pixman_point_fixed_t *top, *bot;
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if (line->p1.y <= line->p2.y)
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{
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top = &line->p1;
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bot = &line->p2;
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}
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else
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{
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top = &line->p2;
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bot = &line->p1;
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}
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pixman_edge_init (e, n, y,
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top->x + x_off_fixed,
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top->y + y_off_fixed,
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bot->x + x_off_fixed,
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bot->y + y_off_fixed);
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}
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PIXMAN_EXPORT void
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pixman_add_traps (pixman_image_t * image,
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int16_t x_off,
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int16_t y_off,
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int ntrap,
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pixman_trap_t * traps)
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{
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int bpp;
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int width;
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int height;
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pixman_fixed_t x_off_fixed;
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pixman_fixed_t y_off_fixed;
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pixman_edge_t l, r;
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pixman_fixed_t t, b;
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_pixman_image_validate (image);
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width = image->bits.width;
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height = image->bits.height;
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bpp = PIXMAN_FORMAT_BPP (image->bits.format);
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x_off_fixed = pixman_int_to_fixed (x_off);
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y_off_fixed = pixman_int_to_fixed (y_off);
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while (ntrap--)
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{
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t = traps->top.y + y_off_fixed;
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if (t < 0)
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t = 0;
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t = pixman_sample_ceil_y (t, bpp);
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b = traps->bot.y + y_off_fixed;
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if (pixman_fixed_to_int (b) >= height)
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b = pixman_int_to_fixed (height) - 1;
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b = pixman_sample_floor_y (b, bpp);
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if (b >= t)
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{
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/* initialize edge walkers */
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pixman_edge_init (&l, bpp, t,
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traps->top.l + x_off_fixed,
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traps->top.y + y_off_fixed,
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traps->bot.l + x_off_fixed,
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traps->bot.y + y_off_fixed);
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pixman_edge_init (&r, bpp, t,
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traps->top.r + x_off_fixed,
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traps->top.y + y_off_fixed,
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traps->bot.r + x_off_fixed,
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traps->bot.y + y_off_fixed);
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pixman_rasterize_edges (image, &l, &r, t, b);
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}
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traps++;
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}
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}
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#if 0
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static void
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dump_image (pixman_image_t *image,
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const char * title)
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{
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int i, j;
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if (!image->type == BITS)
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printf ("%s is not a regular image\n", title);
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if (!image->bits.format == PIXMAN_a8)
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printf ("%s is not an alpha mask\n", title);
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printf ("\n\n\n%s: \n", title);
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for (i = 0; i < image->bits.height; ++i)
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{
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uint8_t *line =
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(uint8_t *)&(image->bits.bits[i * image->bits.rowstride]);
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for (j = 0; j < image->bits.width; ++j)
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printf ("%c", line[j] ? '#' : ' ');
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printf ("\n");
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}
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}
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#endif
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PIXMAN_EXPORT void
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pixman_add_trapezoids (pixman_image_t * image,
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int16_t x_off,
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int y_off,
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int ntraps,
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const pixman_trapezoid_t *traps)
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{
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int i;
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#if 0
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dump_image (image, "before");
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#endif
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for (i = 0; i < ntraps; ++i)
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{
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const pixman_trapezoid_t *trap = &(traps[i]);
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if (!pixman_trapezoid_valid (trap))
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continue;
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pixman_rasterize_trapezoid (image, trap, x_off, y_off);
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}
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#if 0
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dump_image (image, "after");
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#endif
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}
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PIXMAN_EXPORT void
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pixman_rasterize_trapezoid (pixman_image_t * image,
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const pixman_trapezoid_t *trap,
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int x_off,
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int y_off)
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{
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int bpp;
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int width;
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int height;
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pixman_fixed_t x_off_fixed;
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pixman_fixed_t y_off_fixed;
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pixman_edge_t l, r;
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pixman_fixed_t t, b;
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return_if_fail (image->type == BITS);
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_pixman_image_validate (image);
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if (!pixman_trapezoid_valid (trap))
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return;
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width = image->bits.width;
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height = image->bits.height;
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bpp = PIXMAN_FORMAT_BPP (image->bits.format);
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x_off_fixed = pixman_int_to_fixed (x_off);
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y_off_fixed = pixman_int_to_fixed (y_off);
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t = trap->top + y_off_fixed;
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if (t < 0)
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t = 0;
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t = pixman_sample_ceil_y (t, bpp);
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b = trap->bottom + y_off_fixed;
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if (pixman_fixed_to_int (b) >= height)
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b = pixman_int_to_fixed (height) - 1;
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b = pixman_sample_floor_y (b, bpp);
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if (b >= t)
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{
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/* initialize edge walkers */
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pixman_line_fixed_edge_init (&l, bpp, t, &trap->left, x_off, y_off);
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pixman_line_fixed_edge_init (&r, bpp, t, &trap->right, x_off, y_off);
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pixman_rasterize_edges (image, &l, &r, t, b);
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}
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}
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