106 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			106 lines
		
	
	
		
			3.1 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 _RENDEREDGE_H_
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#define _RENDEREDGE_H_
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#include "picturestr.h"
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#define MAX_ALPHA(n)	((1 << (n)) - 1)
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#define N_Y_FRAC(n)	((n) == 1 ? 1 : (1 << ((n)/2)) - 1)
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#define N_X_FRAC(n)	((1 << ((n)/2)) + 1)
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#define STEP_Y_SMALL(n)	(xFixed1 / N_Y_FRAC(n))
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#define STEP_Y_BIG(n)	(xFixed1 - (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
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#define Y_FRAC_FIRST(n)	(STEP_Y_SMALL(n) / 2)
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#define Y_FRAC_LAST(n)	(Y_FRAC_FIRST(n) + (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
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#define STEP_X_SMALL(n)	(xFixed1 / N_X_FRAC(n))
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#define STEP_X_BIG(n)	(xFixed1 - (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
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#define X_FRAC_FIRST(n)	(STEP_X_SMALL(n) / 2)
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#define X_FRAC_LAST(n)	(X_FRAC_FIRST(n) + (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
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#define RenderSamplesX(x,n)	((n) == 1 ? 0 : (xFixedFrac (x) + X_FRAC_FIRST(n)) / STEP_X_SMALL(n))
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/*
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 * An edge structure.  This represents a single polygon edge
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 * and can be quickly stepped across small or large gaps in the
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 * sample grid
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 */
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typedef pixman_edge_t RenderEdge;
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/*
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 * Step across a small sample grid gap
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 */
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#define RenderEdgeStepSmall(edge) { \
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    edge->x += edge->stepx_small;   \
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    edge->e += edge->dx_small;	    \
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    if (edge->e > 0)		    \
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    {				    \
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	edge->e -= edge->dy;	    \
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	edge->x += edge->signdx;    \
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    }				    \
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}
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/*
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 * Step across a large sample grid gap
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 */
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#define RenderEdgeStepBig(edge) {   \
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    edge->x += edge->stepx_big;	    \
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    edge->e += edge->dx_big;	    \
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    if (edge->e > 0)		    \
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    {				    \
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	edge->e -= edge->dy;	    \
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	edge->x += edge->signdx;    \
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    }				    \
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}
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xFixed
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RenderSampleCeilY (xFixed y, int bpp);
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xFixed
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RenderSampleFloorY (xFixed y, int bpp);
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void
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RenderEdgeStep (RenderEdge *e, int n);
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void
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RenderEdgeInit (RenderEdge	*e,
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		int		bpp,
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		xFixed		y_start,
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		xFixed		x_top,
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		xFixed		y_top,
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		xFixed		x_bot,
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		xFixed		y_bot);
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void
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RenderLineFixedEdgeInit (RenderEdge *e,
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			 int	    bpp,
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			 xFixed	    y,
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			 xLineFixed *line,
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			 int	    x_off,
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			 int	    y_off);
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#endif /* _RENDEREDGE_H_ */
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