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kolibrios/programs/develop/libraries/pixman/pixman-trap.c
Sergey Semyonov (Serge) 4dd0483a93 pixman-1.0 
git-svn-id: svn://kolibrios.org@1891 a494cfbc-eb01-0410-851d-a64ba20cac60
2011-02-27 17:46:46 +00:00

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