2 * Copyright © 2004 Keith Packard
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation, and that the name of Keith Packard not be used in
9 * advertising or publicity pertaining to distribution of the software without
10 * specific, written prior permission. Keith Packard makes no
11 * representations about the suitability of this software for any purpose. It
12 * is provided "as is" without express or implied warranty.
14 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
20 * PERFORMANCE OF THIS SOFTWARE.
27 rasterizeEdges (pixman_image_t *image,
35 uint32_t *buf = (image)->bits.bits;
36 int stride = (image)->bits.rowstride;
37 int width = (image)->bits.width;
39 line = buf + pixman_fixed_to_int (y) * stride;
49 /* For the non-antialiased case, round the coordinates up, in effect
50 * sampling the center of the pixel. (The AA case does a similar
51 * adjustment in RenderSamplesX) */
52 lx = l->x + X_FRAC_FIRST(1);
53 rx = r->x + X_FRAC_FIRST(1);
61 if (pixman_fixed_to_int (rx) >= width)
63 rx = pixman_int_to_fixed (width);
65 /* Use the last pixel of the scanline, covered 100%.
66 * We can't use the first pixel following the scanline,
67 * because accessing it could result in a buffer overrun.
69 rx = pixman_int_to_fixed (width) - 1;
72 /* Skip empty (or backwards) sections */
76 /* Find pixel bounds for span */
77 lxi = pixman_fixed_to_int (lx);
78 rxi = pixman_fixed_to_int (rx);
86 int width = rxi - lxi;
92 FbMaskBits (x, width, startmask, nmiddle, endmask);
94 WRITE(image, a, READ(image, a) | startmask);
98 WRITE(image, a++, FB_ALLONES);
100 WRITE(image, a, READ(image, a) | endmask);
104 DefineAlpha(line,lxi);
108 /* Sample coverage for edge pixels */
109 lxs = RenderSamplesX (lx, N_BITS);
110 rxs = RenderSamplesX (rx, N_BITS);
112 /* Add coverage across row */
115 AddAlpha (rxs - lxs);
121 AddAlpha (N_X_FRAC(N_BITS) - lxs);
123 for (xi = lxi + 1; xi < rxi; xi++)
125 AddAlpha (N_X_FRAC(N_BITS));
138 if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
140 RenderEdgeStepSmall (l);
141 RenderEdgeStepSmall (r);
142 y += STEP_Y_SMALL(N_BITS);
147 RenderEdgeStepBig (l);
148 RenderEdgeStepBig (r);
149 y += STEP_Y_BIG(N_BITS);