183 lines
4.4 KiB
C
183 lines
4.4 KiB
C
/*
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* Copyright © 2004 Keith Packard
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name of Keith Packard not be used in
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* advertising or publicity pertaining to distribution of the software without
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* specific, written prior permission. Keith Packard makes no
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* representations about the suitability of this software for any purpose. It
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* is provided "as is" without express or implied warranty.
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*
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* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef rasterize_span
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#endif
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static void
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RASTERIZE_EDGES (pixman_image_t *image,
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pixman_edge_t *l,
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pixman_edge_t *r,
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pixman_fixed_t t,
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pixman_fixed_t b)
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{
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pixman_fixed_t y = t;
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uint32_t *line;
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uint32_t *buf = (image)->bits.bits;
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int stride = (image)->bits.rowstride;
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int width = (image)->bits.width;
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line = buf + pixman_fixed_to_int (y) * stride;
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for (;;)
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{
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pixman_fixed_t lx;
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pixman_fixed_t rx;
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int lxi;
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int rxi;
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lx = l->x;
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rx = r->x;
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#if N_BITS == 1
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/* For the non-antialiased case, round the coordinates up, in effect
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* sampling just slightly to the left of the pixel. This is so that
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* when the sample point lies exactly on the line, we round towards
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* north-west.
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*
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* (The AA case does a similar adjustment in RENDER_SAMPLES_X)
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*/
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lx += X_FRAC_FIRST(1) - pixman_fixed_e;
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rx += X_FRAC_FIRST(1) - pixman_fixed_e;
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#endif
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/* clip X */
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if (lx < 0)
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lx = 0;
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if (pixman_fixed_to_int (rx) >= width)
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#if N_BITS == 1
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rx = pixman_int_to_fixed (width);
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#else
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/* Use the last pixel of the scanline, covered 100%.
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* We can't use the first pixel following the scanline,
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* because accessing it could result in a buffer overrun.
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*/
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rx = pixman_int_to_fixed (width) - 1;
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#endif
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/* Skip empty (or backwards) sections */
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if (rx > lx)
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{
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/* Find pixel bounds for span */
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lxi = pixman_fixed_to_int (lx);
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rxi = pixman_fixed_to_int (rx);
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#if N_BITS == 1
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{
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#define LEFT_MASK(x) \
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(((x) & 0x1f) ? \
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SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
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#define RIGHT_MASK(x) \
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(((32 - (x)) & 0x1f) ? \
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SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
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#define MASK_BITS(x,w,l,n,r) { \
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n = (w); \
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r = RIGHT_MASK ((x) + n); \
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l = LEFT_MASK (x); \
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if (l) { \
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n -= 32 - ((x) & 0x1f); \
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if (n < 0) { \
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n = 0; \
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l &= r; \
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r = 0; \
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} \
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} \
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n >>= 5; \
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}
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uint32_t *a = line;
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uint32_t startmask;
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uint32_t endmask;
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int nmiddle;
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int width = rxi - lxi;
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int x = lxi;
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a += x >> 5;
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x &= 0x1f;
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MASK_BITS (x, width, startmask, nmiddle, endmask);
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if (startmask) {
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WRITE(image, a, READ(image, a) | startmask);
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a++;
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}
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while (nmiddle--)
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WRITE(image, a++, 0xffffffff);
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if (endmask)
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WRITE(image, a, READ(image, a) | endmask);
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}
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#else
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{
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DEFINE_ALPHA(line,lxi);
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int lxs;
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int rxs;
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/* Sample coverage for edge pixels */
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lxs = RENDER_SAMPLES_X (lx, N_BITS);
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rxs = RENDER_SAMPLES_X (rx, N_BITS);
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/* Add coverage across row */
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if (lxi == rxi)
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{
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ADD_ALPHA (rxs - lxs);
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}
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else
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{
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int xi;
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ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
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STEP_ALPHA;
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for (xi = lxi + 1; xi < rxi; xi++)
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{
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ADD_ALPHA (N_X_FRAC(N_BITS));
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STEP_ALPHA;
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}
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ADD_ALPHA (rxs);
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}
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}
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#endif
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}
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if (y == b)
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break;
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#if N_BITS > 1
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if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
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{
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RENDER_EDGE_STEP_SMALL (l);
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RENDER_EDGE_STEP_SMALL (r);
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y += STEP_Y_SMALL(N_BITS);
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}
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else
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#endif
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{
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RENDER_EDGE_STEP_BIG (l);
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RENDER_EDGE_STEP_BIG (r);
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y += STEP_Y_BIG(N_BITS);
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line += stride;
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}
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}
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}
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#undef rasterize_span
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