1 /*
2 * Copyright © 2004 Keith Packard
3 *
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.
13 *
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.
21 */
22
23 #ifndef rasterize_span
24 #endif
25
26 static void
RASTERIZE_EDGES(pixman_image_t * image,pixman_edge_t * l,pixman_edge_t * r,pixman_fixed_t t,pixman_fixed_t b)27 RASTERIZE_EDGES (pixman_image_t *image,
28 pixman_edge_t *l,
29 pixman_edge_t *r,
30 pixman_fixed_t t,
31 pixman_fixed_t b)
32 {
33 pixman_fixed_t y = t;
34 uint32_t *line;
35 uint32_t *buf = (image)->bits.bits;
36 int stride = (image)->bits.rowstride;
37 int width = (image)->bits.width;
38
39 line = buf + pixman_fixed_to_int (y) * stride;
40
41 for (;;)
42 {
43 pixman_fixed_t lx;
44 pixman_fixed_t rx;
45 int lxi;
46 int rxi;
47
48 lx = l->x;
49 rx = r->x;
50 #if N_BITS == 1
51 /* For the non-antialiased case, round the coordinates up, in effect
52 * sampling just slightly to the left of the pixel. This is so that
53 * when the sample point lies exactly on the line, we round towards
54 * north-west.
55 *
56 * (The AA case does a similar adjustment in RENDER_SAMPLES_X)
57 */
58 lx += X_FRAC_FIRST(1) - pixman_fixed_e;
59 rx += X_FRAC_FIRST(1) - pixman_fixed_e;
60 #endif
61 /* clip X */
62 if (lx < 0)
63 lx = 0;
64 if (pixman_fixed_to_int (rx) >= width)
65 #if N_BITS == 1
66 rx = pixman_int_to_fixed (width);
67 #else
68 /* Use the last pixel of the scanline, covered 100%.
69 * We can't use the first pixel following the scanline,
70 * because accessing it could result in a buffer overrun.
71 */
72 rx = pixman_int_to_fixed (width) - 1;
73 #endif
74
75 /* Skip empty (or backwards) sections */
76 if (rx > lx)
77 {
78
79 /* Find pixel bounds for span */
80 lxi = pixman_fixed_to_int (lx);
81 rxi = pixman_fixed_to_int (rx);
82
83 #if N_BITS == 1
84 {
85
86 #define LEFT_MASK(x) \
87 (((x) & 0x1f) ? \
88 SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
89 #define RIGHT_MASK(x) \
90 (((32 - (x)) & 0x1f) ? \
91 SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
92
93 #define MASK_BITS(x,w,l,n,r) { \
94 n = (w); \
95 r = RIGHT_MASK ((x) + n); \
96 l = LEFT_MASK (x); \
97 if (l) { \
98 n -= 32 - ((x) & 0x1f); \
99 if (n < 0) { \
100 n = 0; \
101 l &= r; \
102 r = 0; \
103 } \
104 } \
105 n >>= 5; \
106 }
107
108 uint32_t *a = line;
109 uint32_t startmask;
110 uint32_t endmask;
111 int nmiddle;
112 int width = rxi - lxi;
113 int x = lxi;
114
115 a += x >> 5;
116 x &= 0x1f;
117
118 MASK_BITS (x, width, startmask, nmiddle, endmask);
119
120 if (startmask) {
121 WRITE(image, a, READ(image, a) | startmask);
122 a++;
123 }
124 while (nmiddle--)
125 WRITE(image, a++, 0xffffffff);
126 if (endmask)
127 WRITE(image, a, READ(image, a) | endmask);
128 }
129 #else
130 {
131 DEFINE_ALPHA(line,lxi);
132 int lxs;
133 int rxs;
134
135 /* Sample coverage for edge pixels */
136 lxs = RENDER_SAMPLES_X (lx, N_BITS);
137 rxs = RENDER_SAMPLES_X (rx, N_BITS);
138
139 /* Add coverage across row */
140 if (lxi == rxi)
141 {
142 ADD_ALPHA (rxs - lxs);
143 }
144 else
145 {
146 int xi;
147
148 ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
149 STEP_ALPHA;
150 for (xi = lxi + 1; xi < rxi; xi++)
151 {
152 ADD_ALPHA (N_X_FRAC(N_BITS));
153 STEP_ALPHA;
154 }
155 ADD_ALPHA (rxs);
156 }
157 }
158 #endif
159 }
160
161 if (y == b)
162 break;
163
164 #if N_BITS > 1
165 if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
166 {
167 RENDER_EDGE_STEP_SMALL (l);
168 RENDER_EDGE_STEP_SMALL (r);
169 y += STEP_Y_SMALL(N_BITS);
170 }
171 else
172 #endif
173 {
174 RENDER_EDGE_STEP_BIG (l);
175 RENDER_EDGE_STEP_BIG (r);
176 y += STEP_Y_BIG(N_BITS);
177 line += stride;
178 }
179 }
180 }
181
182 #undef rasterize_span
183