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 /* we cast to unsigned to get defined behaviour for overflow */
59 lx = (unsigned)lx + X_FRAC_FIRST(1) - pixman_fixed_e;
60 rx = (unsigned)rx + X_FRAC_FIRST(1) - pixman_fixed_e;
61 #endif
62 /* clip X */
63 if (lx < 0)
64 lx = 0;
65 if (pixman_fixed_to_int (rx) >= width)
66 #if N_BITS == 1
67 rx = pixman_int_to_fixed (width);
68 #else
69 /* Use the last pixel of the scanline, covered 100%.
70 * We can't use the first pixel following the scanline,
71 * because accessing it could result in a buffer overrun.
72 */
73 rx = pixman_int_to_fixed (width) - 1;
74 #endif
75
76 /* Skip empty (or backwards) sections */
77 if (rx > lx)
78 {
79
80 /* Find pixel bounds for span */
81 lxi = pixman_fixed_to_int (lx);
82 rxi = pixman_fixed_to_int (rx);
83
84 #if N_BITS == 1
85 {
86
87 #define LEFT_MASK(x) \
88 (((x) & 0x1f) ? \
89 SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
90 #define RIGHT_MASK(x) \
91 (((32 - (x)) & 0x1f) ? \
92 SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
93
94 #define MASK_BITS(x,w,l,n,r) { \
95 n = (w); \
96 r = RIGHT_MASK ((x) + n); \
97 l = LEFT_MASK (x); \
98 if (l) { \
99 n -= 32 - ((x) & 0x1f); \
100 if (n < 0) { \
101 n = 0; \
102 l &= r; \
103 r = 0; \
104 } \
105 } \
106 n >>= 5; \
107 }
108
109 uint32_t *a = line;
110 uint32_t startmask;
111 uint32_t endmask;
112 int nmiddle;
113 int width = rxi - lxi;
114 int x = lxi;
115
116 a += x >> 5;
117 x &= 0x1f;
118
119 MASK_BITS (x, width, startmask, nmiddle, endmask);
120
121 if (startmask) {
122 WRITE(image, a, READ(image, a) | startmask);
123 a++;
124 }
125 while (nmiddle--)
126 WRITE(image, a++, 0xffffffff);
127 if (endmask)
128 WRITE(image, a, READ(image, a) | endmask);
129 }
130 #else
131 {
132 DEFINE_ALPHA(line,lxi);
133 int lxs;
134 int rxs;
135
136 /* Sample coverage for edge pixels */
137 lxs = RENDER_SAMPLES_X (lx, N_BITS);
138 rxs = RENDER_SAMPLES_X (rx, N_BITS);
139
140 /* Add coverage across row */
141 if (lxi == rxi)
142 {
143 ADD_ALPHA (rxs - lxs);
144 }
145 else
146 {
147 int xi;
148
149 ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
150 STEP_ALPHA;
151 for (xi = lxi + 1; xi < rxi; xi++)
152 {
153 ADD_ALPHA (N_X_FRAC(N_BITS));
154 STEP_ALPHA;
155 }
156 ADD_ALPHA (rxs);
157 }
158 }
159 #endif
160 }
161
162 if (y == b)
163 break;
164
165 #if N_BITS > 1
166 if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
167 {
168 RENDER_EDGE_STEP_SMALL (l);
169 RENDER_EDGE_STEP_SMALL (r);
170 y += STEP_Y_SMALL(N_BITS);
171 }
172 else
173 #endif
174 {
175 RENDER_EDGE_STEP_BIG (l);
176 RENDER_EDGE_STEP_BIG (r);
177 y += STEP_Y_BIG(N_BITS);
178 line += stride;
179 }
180 }
181 }
182
183 #undef rasterize_span
184