144 lines
3.1 KiB
C
144 lines
3.1 KiB
C
/*
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* $Id$
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*
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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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#ifdef HAVE_DIX_CONFIG_H
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#include <dix-config.h>
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#endif
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#ifndef rasterizeSpan
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#endif
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static void
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rasterizeEdges (FbBits *buf,
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int width,
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int stride,
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RenderEdge *l,
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RenderEdge *r,
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xFixed t,
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xFixed b)
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{
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xFixed y = t;
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FbBits *line;
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line = buf + xFixedToInt (y) * stride;
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for (;;)
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{
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xFixed lx, rx;
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int lxi, rxi;
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/* clip X */
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lx = l->x;
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if (lx < 0)
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lx = 0;
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rx = r->x;
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if (xFixedToInt (rx) >= width)
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rx = IntToxFixed (width);
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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 = xFixedToInt (lx);
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rxi = xFixedToInt (rx);
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#if N_BITS == 1
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{
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FbBits *a = line;
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FbBits startmask, 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 >> FB_SHIFT;
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x &= FB_MASK;
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FbMaskBits (x, width, startmask, nmiddle, endmask);
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if (startmask)
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*a++ |= startmask;
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while (nmiddle--)
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*a++ = FB_ALLONES;
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if (endmask)
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*a |= endmask;
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}
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#else
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{
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DefineAlpha(line,lxi);
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int lxs, rxs;
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/* Sample coverage for edge pixels */
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lxs = RenderSamplesX (lx, N_BITS);
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rxs = RenderSamplesX (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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AddAlpha (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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AddAlpha (N_X_FRAC(N_BITS) - lxs);
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StepAlpha;
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for (xi = lxi + 1; xi < rxi; xi++)
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{
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AddAlpha (N_X_FRAC(N_BITS));
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StepAlpha;
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}
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/* Do not add in a 0 alpha here. This check is necessary
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* to avoid a buffer overrun when rx is exactly on a pixel
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* boundary.
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*/
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if (rxs != 0)
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AddAlpha (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 (xFixedFrac (y) != Y_FRAC_LAST(N_BITS))
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{
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RenderEdgeStepSmall (l);
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RenderEdgeStepSmall (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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RenderEdgeStepBig (l);
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RenderEdgeStepBig (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 rasterizeSpan
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