IABSD.fr/xenocara/xserver/fb/fbedgeimp.h

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• Author : matthieu
  Date : 2006-11-26 18:13:41
  Hash : 889b8606
  Message : Importing xserver from X.Org 7.2RC2

• xserver/fb/fbedgeimp.h

• /*
   * $Id: fbedgeimp.h,v 1.1.1.1 2006/11/26 18:15:35 matthieu Exp $
   *
   * Copyright © 2004 Keith Packard
   *
   * Permission to use, copy, modify, distribute, and sell this software and its
   * documentation for any purpose is hereby granted without fee, provided that
   * the above copyright notice appear in all copies and that both that
   * copyright notice and this permission notice appear in supporting
   * documentation, and that the name of Keith Packard not be used in
   * advertising or publicity pertaining to distribution of the software without
   * specific, written prior permission.  Keith Packard makes no
   * representations about the suitability of this software for any purpose.  It
   * is provided "as is" without express or implied warranty.
   *
   * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
   * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
   * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
   * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
   * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
   * PERFORMANCE OF THIS SOFTWARE.
   */
  
  #ifdef HAVE_DIX_CONFIG_H
  #include <dix-config.h>
  #endif
  
  #ifndef rasterizeSpan
  #endif
  
  static void
  rasterizeEdges (FbBits		*buf,
  		int		width,
  		int		stride,
  		RenderEdge	*l,
  		RenderEdge	*r,
  		xFixed		t,
  		xFixed		b)
  {
      xFixed  y = t;
      FbBits  *line;
      
      line = buf + xFixedToInt (y) * stride;
      
      for (;;)
      {
  	xFixed	lx, rx;
  	int	lxi, rxi;
  	
  	/* clip X */
  	lx = l->x;
  	if (lx < 0)
  	    lx = 0;
  	rx = r->x;
  	if (xFixedToInt (rx) >= width)
  	    rx = IntToxFixed (width);
  	
  	/* Skip empty (or backwards) sections */
  	if (rx > lx)
  	{
  
  	    /* Find pixel bounds for span */
  	    lxi = xFixedToInt (lx);
  	    rxi = xFixedToInt (rx);
  
  #if N_BITS == 1
  	    {
  		FbBits  *a = line;
  		FbBits  startmask, endmask;
  		int	    nmiddle;
  		int	    width = rxi - lxi;
  		int	    x = lxi;
  
  		a += x >> FB_SHIFT;
  		x &= FB_MASK;
  
  		FbMaskBits (x, width, startmask, nmiddle, endmask);
  		if (startmask)
  		    *a++ |= startmask;
  		while (nmiddle--)
  		    *a++ = FB_ALLONES;
  		if (endmask)
  		    *a |= endmask;
  	    }
  #else
  	    {
  		DefineAlpha(line,lxi);
  		int	    lxs, rxs;
  
  		/* Sample coverage for edge pixels */
  		lxs = RenderSamplesX (lx, N_BITS);
  		rxs = RenderSamplesX (rx, N_BITS);
  
  		/* Add coverage across row */
  		if (lxi == rxi)
  		{
  		    AddAlpha (rxs - lxs);
  		}
  		else
  		{
  		    int	xi;
  
  		    AddAlpha (N_X_FRAC(N_BITS) - lxs);
  		    StepAlpha;
  		    for (xi = lxi + 1; xi < rxi; xi++)
  		    {
  			AddAlpha (N_X_FRAC(N_BITS));
  			StepAlpha;
  		    }
  		    /* Do not add in a 0 alpha here. This check is necessary
  		     * to avoid a buffer overrun when rx is exactly on a pixel
  		     * boundary.
  		     */
  		    if (rxs != 0)
  			AddAlpha (rxs);
  		}
  	    }
  #endif
  	}
  
  	if (y == b)
  	    break;
  
  #if N_BITS > 1
  	if (xFixedFrac (y) != Y_FRAC_LAST(N_BITS))
  	{
  	    RenderEdgeStepSmall (l);
  	    RenderEdgeStepSmall (r);
  	    y += STEP_Y_SMALL(N_BITS);
  	}
  	else
  #endif
  	{
  	    RenderEdgeStepBig (l);
  	    RenderEdgeStepBig (r);
  	    y += STEP_Y_BIG(N_BITS);
  	    line += stride;
  	}
      }
  }
  
  #undef rasterizeSpan