315 lines
8.6 KiB
C
315 lines
8.6 KiB
C
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/*
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* $Id: fbedge.c,v 1.1.1.1 2006/11/26 18:15:37 matthieu Exp $
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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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#include <string.h>
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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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#include "fb.h"
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#ifdef RENDER
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#include "picturestr.h"
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#include "mipict.h"
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#include "renderedge.h"
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#include "fbpict.h"
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/*
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* 4 bit alpha
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*/
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#define N_BITS 4
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#define rasterizeEdges fbRasterizeEdges4
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#if BITMAP_BIT_ORDER == LSBFirst
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#define Shift4(o) ((o) << 2)
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#else
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#define Shift4(o) ((1-(o)) << 2)
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#endif
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#define Get4(x,o) (((x) >> Shift4(o)) & 0xf)
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#define Put4(x,o,v) (((x) & ~(0xf << Shift4(o))) | (((v) & 0xf) << Shift4(o)))
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#define DefineAlpha(line,x) \
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CARD8 *__ap = (CARD8 *) line + ((x) >> 1); \
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int __ao = (x) & 1
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#define StepAlpha ((__ap += __ao), (__ao ^= 1))
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#define AddAlpha(a) { \
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CARD8 __o = *__ap; \
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CARD8 __a = (a) + Get4(__o, __ao); \
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*__ap = Put4 (__o, __ao, __a | (0 - ((__a) >> 4))); \
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}
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#include "fbedgeimp.h"
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#undef AddAlpha
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#undef StepAlpha
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#undef DefineAlpha
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#undef rasterizeEdges
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#undef N_BITS
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/*
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* 1 bit alpha
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*/
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#define N_BITS 1
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#define rasterizeEdges fbRasterizeEdges1
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#include "fbedgeimp.h"
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#undef rasterizeEdges
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#undef N_BITS
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/*
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* 8 bit alpha
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*/
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static INLINE CARD8
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clip255 (int x)
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{
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if (x > 255) return 255;
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return x;
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}
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static INLINE void
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add_saturate_8 (CARD8 *buf, int value, int length)
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{
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while (length--)
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{
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*buf = clip255 (*buf + value);
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buf++;
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}
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}
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/*
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* We want to detect the case where we add the same value to a long
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* span of pixels. The triangles on the end are filled in while we
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* count how many sub-pixel scanlines contribute to the middle section.
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*
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* +--------------------------+
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* fill_height =| \ /
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* +------------------+
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* |================|
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* fill_start fill_end
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*/
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static void
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fbRasterizeEdges8 (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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int fill_start = -1, fill_end = -1;
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int fill_size = 0;
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line = buf + xFixedToInt (y) * stride;
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for (;;)
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{
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CARD8 *ap = (CARD8 *) line;
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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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int lxs, rxs;
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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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/* Sample coverage for edge pixels */
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lxs = RenderSamplesX (lx, 8);
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rxs = RenderSamplesX (rx, 8);
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/* Add coverage across row */
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if (lxi == rxi)
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{
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ap[lxi] = clip255 (ap[lxi] + rxs - lxs);
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}
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else
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{
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ap[lxi] = clip255 (ap[lxi] + N_X_FRAC(8) - lxs);
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/* Move forward so that lxi/rxi is the pixel span */
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lxi++;
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/* Don't bother trying to optimize the fill unless
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* the span is longer than 4 pixels. */
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if (rxi - lxi > 4)
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{
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if (fill_start < 0)
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{
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fill_start = lxi;
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fill_end = rxi;
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fill_size++;
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}
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else
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{
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if (lxi >= fill_end || rxi < fill_start)
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{
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/* We're beyond what we saved, just fill it */
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add_saturate_8 (ap + fill_start,
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fill_size * N_X_FRAC(8),
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fill_end - fill_start);
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fill_start = lxi;
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fill_end = rxi;
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fill_size = 1;
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}
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else
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{
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/* Update fill_start */
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if (lxi > fill_start)
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{
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add_saturate_8 (ap + fill_start,
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fill_size * N_X_FRAC(8),
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lxi - fill_start);
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fill_start = lxi;
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}
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else if (lxi < fill_start)
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{
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add_saturate_8 (ap + lxi, N_X_FRAC(8),
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fill_start - lxi);
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}
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/* Update fill_end */
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if (rxi < fill_end)
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{
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add_saturate_8 (ap + rxi,
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fill_size * N_X_FRAC(8),
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fill_end - rxi);
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fill_end = rxi;
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}
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else if (fill_end < rxi)
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{
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add_saturate_8 (ap + fill_end,
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N_X_FRAC(8),
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rxi - fill_end);
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}
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fill_size++;
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}
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}
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}
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else
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{
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add_saturate_8 (ap + lxi, N_X_FRAC(8), rxi - lxi);
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}
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/* Do not add in a 0 alpha here. This check is
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* necessary to avoid a buffer overrun, (when rx
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* is exactly on a pixel boundary). */
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if (rxs)
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ap[rxi] = clip255 (ap[rxi] + rxs);
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}
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}
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if (y == b) {
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/* We're done, make sure we clean up any remaining fill. */
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if (fill_start != fill_end) {
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if (fill_size == N_Y_FRAC(8))
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{
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memset (ap + fill_start, 0xff, fill_end - fill_start);
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}
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else
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{
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add_saturate_8 (ap + fill_start, fill_size * N_X_FRAC(8),
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fill_end - fill_start);
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}
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}
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break;
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}
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if (xFixedFrac (y) != Y_FRAC_LAST(8))
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{
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RenderEdgeStepSmall (l);
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RenderEdgeStepSmall (r);
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y += STEP_Y_SMALL(8);
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}
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else
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{
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RenderEdgeStepBig (l);
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RenderEdgeStepBig (r);
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y += STEP_Y_BIG(8);
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if (fill_start != fill_end)
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{
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if (fill_size == N_Y_FRAC(8))
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{
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memset (ap + fill_start, 0xff, fill_end - fill_start);
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}
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else
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{
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add_saturate_8 (ap + fill_start, fill_size * N_X_FRAC(8),
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fill_end - fill_start);
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}
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fill_start = fill_end = -1;
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fill_size = 0;
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}
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line += stride;
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}
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}
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}
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void
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fbRasterizeEdges (FbBits *buf,
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int bpp,
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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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switch (bpp) {
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case 1:
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fbRasterizeEdges1 (buf, width, stride, l, r, t, b);
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break;
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case 4:
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fbRasterizeEdges4 (buf, width, stride, l, r, t, b);
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break;
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case 8:
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fbRasterizeEdges8 (buf, width, stride, l, r, t, b);
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break;
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}
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}
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#endif /* RENDER */
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