icbltone.c

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

			}
		    }
		}
		if (!w)
		    break;
		/*
		 * Load another set and reset number of available units
		 */
		LoadBits;
		n = unitsPerSrc;
		if (n > w)
		    n = w;
	    }
	}
	/*
	 * Consume stipple bits for endmask
	 */
	if (endmask)
	{
	    if (endNeedsLoad)
	    {
		LoadBits;
	    }
#if FB_UNIT > 32
	    if (pixelsPerDst == 16)
		mask = FbStipple16Bits(FbLeftStipBits(bits,16));
	    else
#endif
		mask = fbBits[FbLeftStipBits(bits,pixelsPerDst)];
#ifndef FBNOPIXADDR
	    if (fbLane)
	    {
		fbTransparentSpan (dst, mask & endmask, fgxor, 1);
	    }
	    else
#endif
	    {
		if (mask || !transparent)
		    FbDoRightMaskByteStippleRRop (dst, mask,
						  fgand, fgxor, bgand, bgxor,
						  endbyte, endmask);
	    }
	}
	dst += dstStride;
	src += srcStride;
    }
}

#ifdef FB_24BIT

/*
 * Crufty macros to initialize the mask array, most of this
 * is to avoid compile-time warnings about shift overflow
 */

#if BITMAP_BIT_ORDER == MSBFirst
#define Mask24Pos(x,r) ((x)*24-(r))
#else
#define Mask24Pos(x,r) ((x)*24-((r) ? 24 - (r) : 0))
#endif

#define Mask24Neg(x,r)	(Mask24Pos(x,r) < 0 ? -Mask24Pos(x,r) : 0)
#define Mask24Check(x,r)    (Mask24Pos(x,r) < 0 ? 0 : \
			     Mask24Pos(x,r) >= FB_UNIT ? 0 : Mask24Pos(x,r))

#define Mask24(x,r) (Mask24Pos(x,r) < FB_UNIT ? \
		     (Mask24Pos(x,r) < 0 ? \
		      0xffffff >> Mask24Neg (x,r) : \
		      0xffffff << Mask24Check(x,r)) : 0)

#define SelMask24(b,n,r)	((((b) >> n) & 1) * Mask24(n,r))

/*
 * Untested for MSBFirst or FB_UNIT == 32
 */

#if FB_UNIT == 64
#define C4_24(b,r) \
    (SelMask24(b,0,r) | \
     SelMask24(b,1,r) | \
     SelMask24(b,2,r) | \
     SelMask24(b,3,r))

#define FbStip24New(rot)    (2 + (rot != 0))
#define FbStip24Len	    4

static const FbBits fbStipple24Bits[3][1 << FbStip24Len] = {
    /* rotate 0 */
    {
	C4_24( 0, 0), C4_24( 1, 0), C4_24( 2, 0), C4_24( 3, 0),
	C4_24( 4, 0), C4_24( 5, 0), C4_24( 6, 0), C4_24( 7, 0),
	C4_24( 8, 0), C4_24( 9, 0), C4_24(10, 0), C4_24(11, 0),
	C4_24(12, 0), C4_24(13, 0), C4_24(14, 0), C4_24(15, 0),
    },
    /* rotate 8 */
    {
	C4_24( 0, 8), C4_24( 1, 8), C4_24( 2, 8), C4_24( 3, 8),
	C4_24( 4, 8), C4_24( 5, 8), C4_24( 6, 8), C4_24( 7, 8),
	C4_24( 8, 8), C4_24( 9, 8), C4_24(10, 8), C4_24(11, 8),
	C4_24(12, 8), C4_24(13, 8), C4_24(14, 8), C4_24(15, 8),
    },
    /* rotate 16 */
    {
	C4_24( 0,16), C4_24( 1,16), C4_24( 2,16), C4_24( 3,16),
	C4_24( 4,16), C4_24( 5,16), C4_24( 6,16), C4_24( 7,16),
	C4_24( 8,16), C4_24( 9,16), C4_24(10,16), C4_24(11,16),
	C4_24(12,16), C4_24(13,16), C4_24(14,16), C4_24(15,16),
    }
};

#endif

#if FB_UNIT == 32
#define C2_24(b,r)  \
    (SelMask24(b,0,r) | \
     SelMask24(b,1,r))

#define FbStip24Len	    2
#if BITMAP_BIT_ORDER == MSBFirst
#define FbStip24New(rot)    (1 + (rot == 0))
#else
#define FbStip24New(rot)    (1 + (rot == 8))
#endif

static const FbBits fbStipple24Bits[3][1 << FbStip24Len] = {
    /* rotate 0 */
    {
	C2_24( 0, 0), C2_24 ( 1, 0), C2_24 ( 2, 0), C2_24 ( 3, 0),
    },
    /* rotate 8 */
    {
	C2_24( 0, 8), C2_24 ( 1, 8), C2_24 ( 2, 8), C2_24 ( 3, 8),
    },
    /* rotate 16 */
    {
	C2_24( 0,16), C2_24 ( 1,16), C2_24 ( 2,16), C2_24 ( 3,16),
    }
};
#endif

#if BITMAP_BIT_ORDER == LSBFirst

#define FbMergeStip24Bits(left, right, new) \
	(FbStipLeft (left, new) | FbStipRight ((right), (FbStip24Len - (new))))

#define FbMergePartStip24Bits(left, right, llen, rlen) \
	(left | FbStipRight(right, llen))

#else

#define FbMergeStip24Bits(left, right, new) \
	((FbStipLeft (left, new) & ((1 << FbStip24Len) - 1)) | right)

#define FbMergePartStip24Bits(left, right, llen, rlen) \
	(FbStipLeft(left, rlen) | right)

#endif

#define fbFirstStipBits(len,stip) {\
    int	__len = (len); \
    if (len <= remain) { \
	stip = FbLeftStipBits(bits, len); \
    } else { \
	stip = FbLeftStipBits(bits, remain); \
	bits = *src++; \
	__len = (len) - remain; \
	stip = FbMergePartStip24Bits(stip, FbLeftStipBits(bits, __len), \
				     remain, __len); \
	remain = FB_STIP_UNIT; \
    } \
    bits = FbStipLeft (bits, __len); \
    remain -= __len; \
}

#define fbInitStipBits(offset,len,stip) {\
    bits = FbStipLeft (*src++,offset); \
    remain = FB_STIP_UNIT - offset; \
    fbFirstStipBits(len,stip); \
    stip = FbMergeStip24Bits (0, stip, len); \
}

#define fbNextStipBits(rot,stip) {\
    int	    __new = FbStip24New(rot); \
    FbStip  __right; \
    fbFirstStipBits(__new, __right); \
    stip = FbMergeStip24Bits (stip, __right, __new); \
    rot = FbNext24Rot (rot); \
}

/*
 * Use deep mask tables that incorporate rotation, pull
 * a variable number of bits out of the stipple and
 * reuse the right bits as needed for the next write
 *
 * Yes, this is probably too much code, but most 24-bpp screens
 * have no acceleration so this code is used for stipples, copyplane
 * and text
 */
void
fbBltOne24 (FbStip	*srcLine,
	    FbStride	srcStride,  /* FbStip units per scanline */
	    int		srcX,	    /* bit position of source */
	    FbBits	*dst,
	    FbStride	dstStride,  /* FbBits units per scanline */
	    int		dstX,	    /* bit position of dest */
	    int		dstBpp,	    /* bits per destination unit */

	    int		width,	    /* width in bits of destination */
	    int		height,	    /* height in scanlines */

	    FbBits	fgand,	    /* rrop values */
	    FbBits	fgxor,
	    FbBits	bgand,
	    FbBits	bgxor)
{
    FbStip	*src;
    FbBits	leftMask, rightMask, mask;
    int		nlMiddle, nl;
    FbStip	stip, bits;
    int		remain;
    int		dstS;
    int		firstlen;
    int		rot0, rot;
    int		nDst;

    srcLine += srcX >> FB_STIP_SHIFT;
    dst += dstX >> FB_SHIFT;
    srcX &= FB_STIP_MASK;
    dstX &= FB_MASK;
    rot0 = FbFirst24Rot (dstX);

    FbMaskBits (dstX, width, leftMask, nlMiddle, rightMask);

    dstS = (dstX + 23) / 24;
    firstlen = FbStip24Len - dstS;

    nDst = nlMiddle;
    if (leftMask)
	nDst++;
    dstStride -= nDst;

    /* opaque copy */
    if (bgand == 0 && fgand == 0)
    {
	while (height--)
	{
	    rot = rot0;
	    src = srcLine;
	    srcLine += srcStride;
	    fbInitStipBits (srcX,firstlen, stip);
	    if (leftMask)
	    {
		mask = fbStipple24Bits[rot >> 3][stip];
		*dst = (*dst & ~leftMask) | (FbOpaqueStipple (mask,
							      FbRot24(fgxor, rot),
							      FbRot24(bgxor, rot))
					     & leftMask);
		dst++;
		fbNextStipBits(rot,stip);
	    }
	    nl = nlMiddle;
	    while (nl--)
	    {
		mask = fbStipple24Bits[rot>>3][stip];
		*dst = FbOpaqueStipple (mask,
					FbRot24(fgxor, rot),
					FbRot24(bgxor, rot));
		dst++;
		fbNextStipBits(rot,stip);
	    }
	    if (rightMask)
	    {
		mask = fbStipple24Bits[rot >> 3][stip];
		*dst = (*dst & ~rightMask) | (FbOpaqueStipple (mask,
							       FbRot24(fgxor, rot),
							       FbRot24(bgxor, rot))
					      & rightMask);
	    }
	    dst += dstStride;
	    src += srcStride;
	}
    }
    /* transparent copy */
    else if (bgand == FB_ALLONES && bgxor == 0 && fgand == 0)
    {
	while (height--)
	{
	    rot = rot0;
	    src = srcLine;
	    srcLine += srcStride;
	    fbInitStipBits (srcX, firstlen, stip);
	    if (leftMask)
	    {
		if (stip)
		{
		    mask = fbStipple24Bits[rot >> 3][stip] & leftMask;
		    *dst = (*dst & ~mask) | (FbRot24(fgxor, rot) & mask);
		}
		dst++;
		fbNextStipBits (rot, stip);
	    }
	    nl = nlMiddle;
	    while (nl--)
	    {
		if (stip)
		{
		    mask = fbStipple24Bits[rot>>3][stip];
		    *dst = (*dst & ~mask) | (FbRot24(fgxor,rot) & mask);
		}
		dst++;
		fbNextStipBits (rot, stip);
	    }
	    if (rightMask)
	    {
		if (stip)
		{
		    mask = fbStipple24Bits[rot >> 3][stip] & rightMask;
		    *dst = (*dst & ~mask) | (FbRot24(fgxor, rot) & mask);
		}
	    }
	    dst += dstStride;
	}
    }
    else
    {
	while (height--)
	{
	    rot = rot0;
	    src = srcLine;
	    srcLine += srcStride;
	    fbInitStipBits (srcX, firstlen, stip);
	    if (leftMask)
	    {
		mask = fbStipple24Bits[rot >> 3][stip];
		*dst = FbStippleRRopMask (*dst, mask,
					  FbRot24(fgand, rot),
					  FbRot24(fgxor, rot),
					  FbRot24(bgand, rot),
					  FbRot24(bgxor, rot),
					  leftMask);
		dst++;
		fbNextStipBits(rot,stip);
	    }
	    nl = nlMiddle;
	    while (nl--)
	    {
		mask = fbStipple24Bits[rot >> 3][stip];
		*dst = FbStippleRRop (*dst, mask,
				      FbRot24(fgand, rot),
				      FbRot24(fgxor, rot),
				      FbRot24(bgand, rot),
				      FbRot24(bgxor, rot));
		dst++;
		fbNextStipBits(rot,stip);
	    }
	    if (rightMask)
	    {
		mask = fbStipple24Bits[rot >> 3][stip];
		*dst = FbStippleRRopMask (*dst, mask,
					  FbRot24(fgand, rot),
					  FbRot24(fgxor, rot),
					  FbRot24(bgand, rot),
					  FbRot24(bgxor, rot),
					  rightMask);
	    }
	    dst += dstStride;
	}
    }
}
#endif