fbpict.h

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

/*
 * Copyright © 2000 Keith Packard
 *             2005 Lars Knoll & Zack Rusin, Trolltech
 *
 * 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.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS 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.
 */

#ifndef _FBPICT_H_
#define _FBPICT_H_

#include "pixman-xserver-compat.h"
#include "renderedge.h"

#define FbIntMult(a,b,t) ( (t) = (a) * (b) + 0x80, ( ( ( (t)>>8 ) + (t) )>>8 ) )
#define FbIntDiv(a,b)	 (((CARD16) (a) * 255) / (b))

#define FbGet8(v,i)   ((CARD16) (CARD8) ((v) >> i))

/*
 * There are two ways of handling alpha -- either as a single unified value or
 * a separate value for each component, hence each macro must have two
 * versions.  The unified alpha version has a 'U' at the end of the name,
 * the component version has a 'C'.  Similarly, functions which deal with
 * this difference will have two versions using the same convention.
 */

#define FbOverU(x,y,i,a,t) ((t) = FbIntMult(FbGet8(y,i),(a),(t)) + FbGet8(x,i),\
			   (CARD32) ((CARD8) ((t) | (0 - ((t) >> 8)))) << (i))

#define FbOverC(x,y,i,a,t) ((t) = FbIntMult(FbGet8(y,i),FbGet8(a,i),(t)) + FbGet8(x,i),\
			    (CARD32) ((CARD8) ((t) | (0 - ((t) >> 8)))) << (i))

#define FbInU(x,i,a,t) ((CARD32) FbIntMult(FbGet8(x,i),(a),(t)) << (i))

#define FbInC(x,i,a,t) ((CARD32) FbIntMult(FbGet8(x,i),FbGet8(a,i),(t)) << (i))

#define FbGen(x,y,i,ax,ay,t,u,v) ((t) = (FbIntMult(FbGet8(y,i),ay,(u)) + \
					 FbIntMult(FbGet8(x,i),ax,(v))),\
				  (CARD32) ((CARD8) ((t) | \
						     (0 - ((t) >> 8)))) << (i))

#define FbAdd(x,y,i,t)	((t) = FbGet8(x,i) + FbGet8(y,i), \
			 (CARD32) ((CARD8) ((t) | (0 - ((t) >> 8)))) << (i))

#define Alpha(x) ((x) >> 24)
#define Red(x) (((x) >> 16) & 0xff)
#define Green(x) (((x) >> 8) & 0xff)
#define Blue(x) ((x) & 0xff)

#define IsRGB(pict) ((pict)->image_format.red > (pict)->image_format.blue)

#define fbComposeGetSolid(pict, dest, bits) { \
    FbBits	*__bits__; \
    FbStride	__stride__; \
    int		__bpp__; \
    int		__xoff__,__yoff__; \
\
    fbGetDrawable((pict)->pDrawable,__bits__,__stride__,__bpp__,__xoff__,__yoff__); \
    switch (__bpp__) { \
    case 32: \
	(bits) = *(CARD32 *) __bits__; \
	break; \
    case 24: \
	(bits) = Fetch24 ((CARD8 *) __bits__); \
	break; \
    case 16: \
	(bits) = *(CARD16 *) __bits__; \
	(bits) = cvt0565to0888(bits); \
	break; \
    case 8: \
	(bits) = *(CARD8 *) __bits__; \
	(bits) = (bits) << 24; \
	break; \
    case 1: \
	(bits) = *(CARD32 *) __bits__; \
	(bits) = FbLeftStipBits((bits),1) ? 0xff000000 : 0x00000000;\
	break; \
    default: \
	return; \
    } \
    /* manage missing src alpha */ \
    if ((pict)->image_format.alphaMask == 0) \
	(bits) |= 0xff000000; \
    /* Handle RGB/BGR mismatch */ \
    if (dest && IsRGB(dest) != IsRGB(pict)) \
        bits = (((bits & 0xff000000)) | \
		((bits & 0x00ff0000) >> 16) | \
		((bits & 0x0000ff00)) | \
		((bits & 0x000000ff) << 16)); \
}

#define fbComposeGetStart(pict,x,y,type,stride,line,mul) {\
    FbBits	*__bits__; \
    FbStride	__stride__; \
    int		__bpp__; \
    int		__xoff__,__yoff__; \
\
    fbGetDrawable((pict)->pDrawable,__bits__,__stride__,__bpp__,__xoff__,__yoff__); \
    (stride) = __stride__ * sizeof (FbBits) / sizeof (type); \
    (line) = ((type *) __bits__) + (stride) * ((y) + __yoff__) + (mul) * ((x) + __xoff__); \
}

#define cvt8888to0565(s)    ((((s) >> 3) & 0x001f) | \
			     (((s) >> 5) & 0x07e0) | \
			     (((s) >> 8) & 0xf800))
#define cvt0565to0888(s)    (((((s) << 3) & 0xf8) | (((s) >> 2) & 0x7)) | \
			     ((((s) << 5) & 0xfc00) | (((s) >> 1) & 0x300)) | \
			     ((((s) << 8) & 0xf80000) | (((s) << 3) & 0x70000)))

#if IMAGE_BYTE_ORDER == MSBFirst
#define Fetch24(a)  ((unsigned long) (a) & 1 ? \
		     ((*(a) << 16) | *((CARD16 *) ((a)+1))) : \
		     ((*((CARD16 *) (a)) << 8) | *((a)+2)))
#define Store24(a,v) ((unsigned long) (a) & 1 ? \
		      ((*(a) = (CARD8) ((v) >> 16)), \
		       (*((CARD16 *) ((a)+1)) = (CARD16) (v))) : \
		      ((*((CARD16 *) (a)) = (CARD16) ((v) >> 8)), \
		       (*((a)+2) = (CARD8) (v))))
#else
#define Fetch24(a)  ((unsigned long) (a) & 1 ? \
		     ((*(a)) | (*((CARD16 *) ((a)+1)) << 8)) : \
		     ((*((CARD16 *) (a))) | (*((a)+2) << 16)))
#define Store24(a,v) ((unsigned long) (a) & 1 ? \
		      ((*(a) = (CARD8) (v)), \
		       (*((CARD16 *) ((a)+1)) = (CARD16) ((v) >> 8))) : \
		      ((*((CARD16 *) (a)) = (CARD16) (v)),\
		       (*((a)+2) = (CARD8) ((v) >> 16))))
#endif

/*
  The methods below use some tricks to be able to do two color
  components at the same time.
*/

/*
  x_c = (x_c * a) / 255
*/
#define FbByteMul(x, a) do {                                      \
        CARD32 t = ((x & 0xff00ff) * a) + 0x800080;               \
        t = (t + ((t >> 8) & 0xff00ff)) >> 8;                     \
        t &= 0xff00ff;                                            \
                                                                  \
        x = (((x >> 8) & 0xff00ff) * a) + 0x800080;               \
        x = (x + ((x >> 8) & 0xff00ff));                          \
        x &= 0xff00ff00;                                          \
        x += t;                                                   \
    } while (0)

/*
  x_c = (x_c * a) / 255 + y
*/
#define FbByteMulAdd(x, a, y) do {                                \
        CARD32 t = ((x & 0xff00ff) * a) + 0x800080;               \
        t = (t + ((t >> 8) & 0xff00ff)) >> 8;                     \
        t &= 0xff00ff;                                            \
        t += y & 0xff00ff;                                        \
        t |= 0x1000100 - ((t >> 8) & 0xff00ff);                   \
        t &= 0xff00ff;                                            \
                                                                  \
        x = (((x >> 8) & 0xff00ff) * a) + 0x800080;                 \
        x = (x + ((x >> 8) & 0xff00ff)) >> 8;                       \
        x &= 0xff00ff;                                              \
        x += (y >> 8) & 0xff00ff;                                   \
        x |= 0x1000100 - ((t >> 8) & 0xff00ff);                     \