| 1 | /*
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| 2 | * Copyright © 2004 Keith Packard
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| 3 | *
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| 4 | * Permission to use, copy, modify, distribute, and sell this software and its
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| 5 | * documentation for any purpose is hereby granted without fee, provided that
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| 6 | * the above copyright notice appear in all copies and that both that
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| 7 | * copyright notice and this permission notice appear in supporting
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| 8 | * documentation, and that the name of Keith Packard not be used in
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| 9 | * advertising or publicity pertaining to distribution of the software without
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| 10 | * specific, written prior permission. Keith Packard makes no
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| 11 | * representations about the suitability of this software for any purpose. It
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| 12 | * is provided "as is" without express or implied warranty.
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| 13 | *
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| 14 | * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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| 15 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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| 16 | * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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| 17 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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| 18 | * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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| 19 | * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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| 20 | * PERFORMANCE OF THIS SOFTWARE.
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| 21 | */
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| 22 |
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| 23 | #ifndef rasterize_span
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| 24 | #endif
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| 25 |
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| 26 | static void
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| 27 | RASTERIZE_EDGES (pixman_image_t *image,
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| 28 | pixman_edge_t *l,
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| 29 | pixman_edge_t *r,
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| 30 | pixman_fixed_t t,
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| 31 | pixman_fixed_t b)
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| 32 | {
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| 33 | pixman_fixed_t y = t;
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| 34 | uint32_t *line;
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| 35 | uint32_t *buf = (image)->bits.bits;
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| 36 | int stride = (image)->bits.rowstride;
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| 37 | int width = (image)->bits.width;
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| 38 |
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| 39 | line = buf + pixman_fixed_to_int (y) * stride;
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| 40 |
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| 41 | for (;;)
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| 42 | {
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| 43 | pixman_fixed_t lx;
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| 44 | pixman_fixed_t rx;
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| 45 | int lxi;
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| 46 | int rxi;
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| 47 |
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| 48 | lx = l->x;
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| 49 | rx = r->x;
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| 50 | #if N_BITS == 1
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| 51 | /* For the non-antialiased case, round the coordinates up, in effect
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| 52 | * sampling the center of the pixel. (The AA case does a similar
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| 53 | * adjustment in RENDER_SAMPLES_X) */
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| 54 | lx += X_FRAC_FIRST(1);
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| 55 | rx += X_FRAC_FIRST(1);
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| 56 | #endif
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| 57 | /* clip X */
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| 58 | if (lx < 0)
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| 59 | lx = 0;
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| 60 | if (pixman_fixed_to_int (rx) >= width)
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| 61 | #if N_BITS == 1
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| 62 | rx = pixman_int_to_fixed (width);
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| 63 | #else
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| 64 | /* Use the last pixel of the scanline, covered 100%.
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| 65 | * We can't use the first pixel following the scanline,
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| 66 | * because accessing it could result in a buffer overrun.
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| 67 | */
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| 68 | rx = pixman_int_to_fixed (width) - 1;
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| 69 | #endif
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| 70 |
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| 71 | /* Skip empty (or backwards) sections */
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| 72 | if (rx > lx)
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| 73 | {
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| 74 |
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| 75 | /* Find pixel bounds for span */
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| 76 | lxi = pixman_fixed_to_int (lx);
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| 77 | rxi = pixman_fixed_to_int (rx);
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| 78 |
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| 79 | #if N_BITS == 1
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| 80 | {
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| 81 |
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| 82 | #ifdef WORDS_BIGENDIAN
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| 83 | # define SCREEN_SHIFT_LEFT(x,n) ((x) << (n))
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| 84 | # define SCREEN_SHIFT_RIGHT(x,n) ((x) >> (n))
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| 85 | #else
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| 86 | # define SCREEN_SHIFT_LEFT(x,n) ((x) >> (n))
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| 87 | # define SCREEN_SHIFT_RIGHT(x,n) ((x) << (n))
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| 88 | #endif
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| 89 |
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| 90 | #define LEFT_MASK(x) \
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| 91 | (((x) & 0x1f) ? \
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| 92 | SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
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| 93 | #define RIGHT_MASK(x) \
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| 94 | (((32 - (x)) & 0x1f) ? \
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| 95 | SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
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| 96 |
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| 97 | #define MASK_BITS(x,w,l,n,r) { \
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| 98 | n = (w); \
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| 99 | r = RIGHT_MASK ((x) + n); \
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| 100 | l = LEFT_MASK (x); \
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| 101 | if (l) { \
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| 102 | n -= 32 - ((x) & 0x1f); \
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| 103 | if (n < 0) { \
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| 104 | n = 0; \
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| 105 | l &= r; \
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| 106 | r = 0; \
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| 107 | } \
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| 108 | } \
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| 109 | n >>= 5; \
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| 110 | }
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| 111 |
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| 112 | uint32_t *a = line;
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| 113 | uint32_t startmask;
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| 114 | uint32_t endmask;
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| 115 | int nmiddle;
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| 116 | int width = rxi - lxi;
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| 117 | int x = lxi;
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| 118 |
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| 119 | a += x >> 5;
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| 120 | x &= 0x1f;
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| 121 |
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| 122 | MASK_BITS (x, width, startmask, nmiddle, endmask);
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| 123 |
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| 124 | if (startmask) {
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| 125 | WRITE(image, a, READ(image, a) | startmask);
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| 126 | a++;
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| 127 | }
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| 128 | while (nmiddle--)
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| 129 | WRITE(image, a++, 0xffffffff);
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| 130 | if (endmask)
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| 131 | WRITE(image, a, READ(image, a) | endmask);
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| 132 | }
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| 133 | #else
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| 134 | {
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| 135 | DEFINE_ALPHA(line,lxi);
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| 136 | int lxs;
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| 137 | int rxs;
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| 138 |
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| 139 | /* Sample coverage for edge pixels */
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| 140 | lxs = RENDER_SAMPLES_X (lx, N_BITS);
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| 141 | rxs = RENDER_SAMPLES_X (rx, N_BITS);
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| 142 |
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| 143 | /* Add coverage across row */
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| 144 | if (lxi == rxi)
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| 145 | {
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| 146 | ADD_ALPHA (rxs - lxs);
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| 147 | }
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| 148 | else
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| 149 | {
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| 150 | int xi;
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| 151 |
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| 152 | ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
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| 153 | STEP_ALPHA;
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| 154 | for (xi = lxi + 1; xi < rxi; xi++)
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| 155 | {
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| 156 | ADD_ALPHA (N_X_FRAC(N_BITS));
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| 157 | STEP_ALPHA;
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| 158 | }
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| 159 | ADD_ALPHA (rxs);
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| 160 | }
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| 161 | }
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| 162 | #endif
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| 163 | }
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| 164 |
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| 165 | if (y == b)
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| 166 | break;
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| 167 |
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| 168 | #if N_BITS > 1
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| 169 | if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
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| 170 | {
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| 171 | RENDER_EDGE_STEP_SMALL (l);
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| 172 | RENDER_EDGE_STEP_SMALL (r);
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| 173 | y += STEP_Y_SMALL(N_BITS);
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| 174 | }
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| 175 | else
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| 176 | #endif
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| 177 | {
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| 178 | RENDER_EDGE_STEP_BIG (l);
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| 179 | RENDER_EDGE_STEP_BIG (r);
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| 180 | y += STEP_Y_BIG(N_BITS);
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| 181 | line += stride;
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| 182 | }
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| 183 | }
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| 184 | }
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| 185 |
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| 186 | #undef rasterize_span
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