315 lines
		
	
	
		
			8.5 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			315 lines
		
	
	
		
			8.5 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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#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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