icblt.c

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

/*
 * Id: $
 *
 * Copyright © 1998 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.
 */

#include "pixman-xserver-compat.h"

#define InitializeShifts(sx,dx,ls,rs) { \
    if (sx != dx) { \
	if (sx > dx) { \
	    ls = sx - dx; \
	    rs = FB_UNIT - ls; \
	} else { \
	    rs = dx - sx; \
	    ls = FB_UNIT - rs; \
	} \
    } \
}

void
fbBlt (FbBits   *srcLine,
       FbStride	srcStride,
       int	srcX,

       FbBits   *dstLine,
       FbStride dstStride,
       int	dstX,

       int	width,
       int	height,

       int	alu,
       FbBits	pm,
       int	bpp,

       Bool	reverse,
       Bool	upsidedown)
{
    FbBits  *src, *dst;
    int	    leftShift, rightShift;
    FbBits  startmask, endmask;
    FbBits  bits, bits1;
    int	    n, nmiddle;
    Bool    destInvarient;
    int	    startbyte, endbyte;
    FbDeclareMergeRop ();

    /* are we just copying multiples of 8 bits?  if so, run, forrest, run!
       the memcpy()'s should be pluggable ala mplayer|xine - perhaps we can get
       one of the above to give up their code for us.
     */
    if((pm==FB_ALLONES) && (alu==GXcopy) && !reverse && (srcX&7)==0 && (dstX&7)==0 && (width&7)==0)
    {
		CARD8 *isrc=(CARD8 *)srcLine;
		CARD8 *idst=(CARD8 *)dstLine;
		int sstride=srcStride*sizeof(FbBits);
		int dstride=dstStride*sizeof(FbBits);
		int j;
		width>>=3;
		isrc+=(srcX>>3);
		idst+=(dstX>>3);
		if(!upsidedown)
			for(j=0;j<height;j++)
				memcpy(idst+j*dstride, isrc+j*sstride, width);
		else
			for(j=(height-1);j>=0;j--)
				memcpy(idst+j*dstride, isrc+j*sstride, width);

		return;
    }

#ifdef FB_24BIT
    if (bpp == 24 && !FbCheck24Pix (pm))
    {
	fbBlt24 (srcLine, srcStride, srcX, dstLine, dstStride, dstX,
		 width, height, alu, pm, reverse, upsidedown);
	return;
    }
#endif
    FbInitializeMergeRop(alu, pm);
    destInvarient = FbDestInvarientMergeRop();
    if (upsidedown)
    {
	srcLine += (height - 1) * (srcStride);
	dstLine += (height - 1) * (dstStride);
	srcStride = -srcStride;
	dstStride = -dstStride;
    }
    FbMaskBitsBytes (dstX, width, destInvarient, startmask, startbyte,
		     nmiddle, endmask, endbyte);
    if (reverse)
    {
	srcLine += ((srcX + width - 1) >> FB_SHIFT) + 1;
	dstLine += ((dstX + width - 1) >> FB_SHIFT) + 1;
	srcX = (srcX + width - 1) & FB_MASK;
	dstX = (dstX + width - 1) & FB_MASK;
    }
    else
    {
	srcLine += srcX >> FB_SHIFT;
	dstLine += dstX >> FB_SHIFT;
	srcX &= FB_MASK;
	dstX &= FB_MASK;
    }
    if (srcX == dstX)
    {
	while (height--)
	{
	    src = srcLine;
	    srcLine += srcStride;
	    dst = dstLine;
	    dstLine += dstStride;
	    if (reverse)
	    {
		if (endmask)
		{
		    bits = *--src;
		    --dst;
		    FbDoRightMaskByteMergeRop(dst, bits, endbyte, endmask);
		}
		n = nmiddle;
		if (destInvarient)
		{
		    while (n--)
			*--dst = FbDoDestInvarientMergeRop(*--src);
		}
		else
		{
		    while (n--)
		    {
			bits = *--src;
			--dst;
			*dst = FbDoMergeRop (bits, *dst);
		    }
		}
		if (startmask)
		{
		    bits = *--src;
		    --dst;
		    FbDoLeftMaskByteMergeRop(dst, bits, startbyte, startmask);
		}
	    }
	    else
	    {
		if (startmask)
		{
		    bits = *src++;
		    FbDoLeftMaskByteMergeRop(dst, bits, startbyte, startmask);
		    dst++;
		}
		n = nmiddle;
		if (destInvarient)
		{
#if 0
		    /*
		     * This provides some speedup on screen->screen blts
		     * over the PCI bus, usually about 10%.  But fb
		     * isn't usually used for this operation...
		     */
		    if (_ca2 + 1 == 0 && _cx2 == 0)
		    {
			FbBits	t1, t2, t3, t4;
			while (n >= 4)
			{
			    t1 = *src++;
			    t2 = *src++;
			    t3 = *src++;
			    t4 = *src++;
			    *dst++ = t1;
			    *dst++ = t2;
			    *dst++ = t3;
			    *dst++ = t4;
			    n -= 4;
			}
		    }
#endif
		    while (n--)
			*dst++ = FbDoDestInvarientMergeRop(*src++);
		}
		else
		{
		    while (n--)
		    {
			bits = *src++;
			*dst = FbDoMergeRop (bits, *dst);
			dst++;
		    }
		}
		if (endmask)
		{
		    bits = *src;
		    FbDoRightMaskByteMergeRop(dst, bits, endbyte, endmask);
		}
	    }
	}
    }
    else
    {
	if (srcX > dstX)
	{
	    leftShift = srcX - dstX;
	    rightShift = FB_UNIT - leftShift;
	}
	else
	{
	    rightShift = dstX - srcX;
	    leftShift = FB_UNIT - rightShift;
	}
	while (height--)
	{
	    src = srcLine;
	    srcLine += srcStride;
	    dst = dstLine;
	    dstLine += dstStride;

	    bits1 = 0;
	    if (reverse)
	    {
		if (srcX < dstX)
		    bits1 = *--src;
		if (endmask)
		{
		    bits = FbScrRight(bits1, rightShift);
		    if (FbScrRight(endmask, leftShift))
		    {
			bits1 = *--src;
			bits |= FbScrLeft(bits1, leftShift);
		    }
		    --dst;
		    FbDoRightMaskByteMergeRop(dst, bits, endbyte, endmask);
		}
		n = nmiddle;
		if (destInvarient)
		{
		    while (n--)
		    {
			bits = FbScrRight(bits1, rightShift);
			bits1 = *--src;
			bits |= FbScrLeft(bits1, leftShift);
			--dst;
			*dst = FbDoDestInvarientMergeRop(bits);
		    }
		}
		else
		{
		    while (n--)
		    {
			bits = FbScrRight(bits1, rightShift);
			bits1 = *--src;
			bits |= FbScrLeft(bits1, leftShift);
			--dst;
			*dst = FbDoMergeRop(bits, *dst);
		    }
		}
		if (startmask)
		{
		    bits = FbScrRight(bits1, rightShift);
		    if (FbScrRight(startmask, leftShift))
		    {
			bits1 = *--src;
			bits |= FbScrLeft(bits1, leftShift);
		    }
		    --dst;
		    FbDoLeftMaskByteMergeRop (dst, bits, startbyte, startmask);
		}
	    }
	    else
	    {
		if (srcX > dstX)
		    bits1 = *src++;
		if (startmask)
		{
		    bits = FbScrLeft(bits1, leftShift);
		    bits1 = *src++;
		    bits |= FbScrRight(bits1, rightShift);
		    FbDoLeftMaskByteMergeRop (dst, bits, startbyte, startmask);
		    dst++;
		}
		n = nmiddle;
		if (destInvarient)
		{
		    while (n--)
		    {
			bits = FbScrLeft(bits1, leftShift);
			bits1 = *src++;
			bits |= FbScrRight(bits1, rightShift);
			*dst = FbDoDestInvarientMergeRop(bits);
			dst++;
		    }
		}
		else
		{
		    while (n--)
		    {
			bits = FbScrLeft(bits1, leftShift);
			bits1 = *src++;
			bits |= FbScrRight(bits1, rightShift);
			*dst = FbDoMergeRop(bits, *dst);
			dst++;
		    }
		}
		if (endmask)
		{
		    bits = FbScrLeft(bits1, leftShift);
		    if (FbScrLeft(endmask, rightShift))
		    {
			bits1 = *src;
			bits |= FbScrRight(bits1, rightShift);
		    }
		    FbDoRightMaskByteMergeRop (dst, bits, endbyte, endmask);
		}
	    }
	}
    }
}

#ifdef FB_24BIT

#undef DEBUG_BLT24
#ifdef DEBUG_BLT24

static unsigned long
getPixel (char *src, int x)
{
    unsigned long   l;

    l = 0;
    memcpy (&l, src + x * 3, 3);
    return l;
}
#endif

static void
fbBlt24Line (FbBits	    *src,
	     int	    srcX,

	     FbBits	    *dst,
	     int	    dstX,

	     int	    width,

	     int	    alu,
	     FbBits	    pm,

	     Bool	    reverse)
{
#ifdef DEBUG_BLT24
    char    *origDst = (char *) dst;
    FbBits  *origLine = dst + ((dstX >> FB_SHIFT) - 1);
    int	    origNlw = ((width + FB_MASK) >> FB_SHIFT) + 3;
    int	    origX = dstX / 24;
#endif

    int	    leftShift, rightShift;
    FbBits  startmask, endmask;
    int	    n;

    FbBits  bits, bits1;
    FbBits  mask;

    int	    rot;
    FbDeclareMergeRop ();

    FbInitializeMergeRop (alu, FB_ALLONES);
    FbMaskBits(dstX, width, startmask, n, endmask);
#ifdef DEBUG_BLT24
    ErrorF ("dstX %d width %d reverse %d\n", dstX, width, reverse);
#endif
    if (reverse)
    {
	src += ((srcX + width - 1) >> FB_SHIFT) + 1;
	dst += ((dstX + width - 1) >> FB_SHIFT) + 1;
	rot = FbFirst24Rot (((dstX + width - 8) & FB_MASK));
	rot = FbPrev24Rot(rot);
#ifdef DEBUG_BLT24
	ErrorF ("dstX + width - 8: %d rot: %d\n", (dstX + width - 8) & FB_MASK, rot);
#endif
	srcX = (srcX + width - 1) & FB_MASK;
	dstX = (dstX + width - 1) & FB_MASK;
    }
    else
    {
	src += srcX >> FB_SHIFT;
	dst += dstX >> FB_SHIFT;
	srcX &= FB_MASK;
	dstX &= FB_MASK;
	rot = FbFirst24Rot (dstX);
#ifdef DEBUG_BLT24
	ErrorF ("dstX: %d rot: %d\n", dstX, rot);
#endif
    }
    mask = FbRot24(pm,rot);
#ifdef DEBUG_BLT24
    ErrorF ("pm 0x%x mask 0x%x\n", pm, mask);
#endif
    if (srcX == dstX)
    {
	if (reverse)
	{
	    if (endmask)
	    {
		bits = *--src;
		--dst;
		*dst = FbDoMaskMergeRop (bits, *dst, mask & endmask);
		mask = FbPrev24Pix (mask);
	    }
	    while (n--)
	    {
		bits = *--src;
		--dst;
		*dst = FbDoMaskMergeRop (bits, *dst, mask);
		mask = FbPrev24Pix (mask);
	    }
	    if (startmask)
	    {
		bits = *--src;
		--dst;
		*dst = FbDoMaskMergeRop(bits, *dst, mask & startmask);
	    }
	}
	else
	{
	    if (startmask)
	    {
		bits = *src++;
		*dst = FbDoMaskMergeRop (bits, *dst, mask & startmask);
		dst++;
		mask = FbNext24Pix(mask);
	    }
	    while (n--)
	    {
		bits = *src++;
		*dst = FbDoMaskMergeRop (bits, *dst, mask);
		dst++;
		mask = FbNext24Pix(mask);
	    }
	    if (endmask)
	    {
		bits = *src;
		*dst = FbDoMaskMergeRop(bits, *dst, mask & endmask);
	    }
	}
    }
    else
    {
	if (srcX > dstX)
	{
	    leftShift = srcX - dstX;
	    rightShift = FB_UNIT - leftShift;
	}
	else
	{
	    rightShift = dstX - srcX;
	    leftShift = FB_UNIT - rightShift;
	}