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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.
*/
#ifndef rasterize_span
#endif
static void
RASTERIZE_EDGES (pixman_image_t *image,
pixman_edge_t *l,
pixman_edge_t *r,
pixman_fixed_t t,
pixman_fixed_t b)
{
pixman_fixed_t y = t;
uint32_t *line;
uint32_t *buf = (image)->bits.bits;
int stride = (image)->bits.rowstride;
int width = (image)->bits.width;
line = buf + pixman_fixed_to_int (y) * stride;
for (;;)
{
pixman_fixed_t lx;
pixman_fixed_t rx;
int lxi;
int rxi;
lx = l->x;
rx = r->x;
#if N_BITS == 1
/* For the non-antialiased case, round the coordinates up, in effect
* sampling just slightly to the left of the pixel. This is so that
* when the sample point lies exactly on the line, we round towards
* north-west.
*
* (The AA case does a similar adjustment in RENDER_SAMPLES_X)
*/
/* we cast to unsigned to get defined behaviour for overflow */
lx = (unsigned)lx + X_FRAC_FIRST(1) - pixman_fixed_e;
rx = (unsigned)rx + X_FRAC_FIRST(1) - pixman_fixed_e;
#endif
/* clip X */
if (lx < 0)
lx = 0;
if (pixman_fixed_to_int (rx) >= width)
#if N_BITS == 1
rx = pixman_int_to_fixed (width);
#else
/* Use the last pixel of the scanline, covered 100%.
* We can't use the first pixel following the scanline,
* because accessing it could result in a buffer overrun.
*/
rx = pixman_int_to_fixed (width) - 1;
#endif
/* Skip empty (or backwards) sections */
if (rx > lx)
{
/* Find pixel bounds for span */
lxi = pixman_fixed_to_int (lx);
rxi = pixman_fixed_to_int (rx);
#if N_BITS == 1
{
#define LEFT_MASK(x) \
(((x) & 0x1f) ? \
SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
#define RIGHT_MASK(x) \
(((32 - (x)) & 0x1f) ? \
SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
#define MASK_BITS(x,w,l,n,r) { \
n = (w); \
r = RIGHT_MASK ((x) + n); \
l = LEFT_MASK (x); \
if (l) { \
n -= 32 - ((x) & 0x1f); \
if (n < 0) { \
n = 0; \
l &= r; \
r = 0; \
} \
} \
n >>= 5; \
}
uint32_t *a = line;
uint32_t startmask;
uint32_t endmask;
int nmiddle;
int width = rxi - lxi;
int x = lxi;
a += x >> 5;
x &= 0x1f;
MASK_BITS (x, width, startmask, nmiddle, endmask);
if (startmask) {
WRITE(image, a, READ(image, a) | startmask);
a++;
}
while (nmiddle--)
WRITE(image, a++, 0xffffffff);
if (endmask)
WRITE(image, a, READ(image, a) | endmask);
}
#else
{
DEFINE_ALPHA(line,lxi);
int lxs;
int rxs;
/* Sample coverage for edge pixels */
lxs = RENDER_SAMPLES_X (lx, N_BITS);
rxs = RENDER_SAMPLES_X (rx, N_BITS);
/* Add coverage across row */
if (lxi == rxi)
{
ADD_ALPHA (rxs - lxs);
}
else
{
int xi;
ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
STEP_ALPHA;
for (xi = lxi + 1; xi < rxi; xi++)
{
ADD_ALPHA (N_X_FRAC(N_BITS));
STEP_ALPHA;
}
ADD_ALPHA (rxs);
}
}
#endif
}
if (y == b)
break;
#if N_BITS > 1
if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
{
RENDER_EDGE_STEP_SMALL (l);
RENDER_EDGE_STEP_SMALL (r);
y += STEP_Y_SMALL(N_BITS);
}
else
#endif
{
RENDER_EDGE_STEP_BIG (l);
RENDER_EDGE_STEP_BIG (r);
y += STEP_Y_BIG(N_BITS);
line += stride;
}
}
}
#undef rasterize_span
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