Line data Source code
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
27 0 : 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 0 : pixman_fixed_t y = t;
34 : uint32_t *line;
35 0 : uint32_t *buf = (image)->bits.bits;
36 0 : int stride = (image)->bits.rowstride;
37 0 : int width = (image)->bits.width;
38 :
39 0 : line = buf + pixman_fixed_to_int (y) * stride;
40 :
41 : for (;;)
42 0 : {
43 : pixman_fixed_t lx;
44 : pixman_fixed_t rx;
45 : int lxi;
46 : int rxi;
47 :
48 0 : lx = l->x;
49 0 : 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 0 : lx = (unsigned)lx + X_FRAC_FIRST(1) - pixman_fixed_e;
60 0 : rx = (unsigned)rx + X_FRAC_FIRST(1) - pixman_fixed_e;
61 : #endif
62 : /* clip X */
63 0 : if (lx < 0)
64 0 : lx = 0;
65 0 : if (pixman_fixed_to_int (rx) >= width)
66 : #if N_BITS == 1
67 0 : 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 0 : rx = pixman_int_to_fixed (width) - 1;
74 : #endif
75 :
76 : /* Skip empty (or backwards) sections */
77 0 : if (rx > lx)
78 : {
79 :
80 : /* Find pixel bounds for span */
81 0 : lxi = pixman_fixed_to_int (lx);
82 0 : 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 0 : uint32_t *a = line;
110 : uint32_t startmask;
111 : uint32_t endmask;
112 : int nmiddle;
113 0 : int width = rxi - lxi;
114 0 : int x = lxi;
115 :
116 0 : a += x >> 5;
117 0 : x &= 0x1f;
118 :
119 0 : MASK_BITS (x, width, startmask, nmiddle, endmask);
120 :
121 0 : if (startmask) {
122 0 : WRITE(image, a, READ(image, a) | startmask);
123 0 : a++;
124 : }
125 0 : while (nmiddle--)
126 0 : WRITE(image, a++, 0xffffffff);
127 0 : if (endmask)
128 0 : WRITE(image, a, READ(image, a) | endmask);
129 : }
130 : #else
131 : {
132 0 : DEFINE_ALPHA(line,lxi);
133 : int lxs;
134 : int rxs;
135 :
136 : /* Sample coverage for edge pixels */
137 0 : lxs = RENDER_SAMPLES_X (lx, N_BITS);
138 0 : rxs = RENDER_SAMPLES_X (rx, N_BITS);
139 :
140 : /* Add coverage across row */
141 0 : if (lxi == rxi)
142 : {
143 0 : ADD_ALPHA (rxs - lxs);
144 : }
145 : else
146 : {
147 : int xi;
148 :
149 0 : ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
150 0 : STEP_ALPHA;
151 0 : for (xi = lxi + 1; xi < rxi; xi++)
152 : {
153 0 : ADD_ALPHA (N_X_FRAC(N_BITS));
154 0 : STEP_ALPHA;
155 : }
156 0 : ADD_ALPHA (rxs);
157 : }
158 : }
159 : #endif
160 : }
161 :
162 0 : if (y == b)
163 0 : break;
164 :
165 : #if N_BITS > 1
166 0 : if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
167 : {
168 0 : RENDER_EDGE_STEP_SMALL (l);
169 0 : RENDER_EDGE_STEP_SMALL (r);
170 0 : y += STEP_Y_SMALL(N_BITS);
171 : }
172 : else
173 : #endif
174 : {
175 0 : RENDER_EDGE_STEP_BIG (l);
176 0 : RENDER_EDGE_STEP_BIG (r);
177 0 : y += STEP_Y_BIG(N_BITS);
178 0 : line += stride;
179 : }
180 : }
181 0 : }
182 :
183 : #undef rasterize_span
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