icbltone.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"

/*
 *  Example: srcX = 13 dstX = 8	(FB unit 32 dstBpp 8)
 *
 *	**** **** **** **** **** **** **** ****
 *			^
 *	********  ********  ********  ********
 *		  ^
 *  leftShift = 12
 *  rightShift = 20
 *
 *  Example: srcX = 0 dstX = 8 (FB unit 32 dstBpp 8)
 *
 *	**** **** **** **** **** **** **** ****
 *	^
 *	********  ********  ********  ********
 *		  ^
 *
 *  leftShift = 24
 *  rightShift = 8
 */

#define LoadBits {\
    if (leftShift) { \
	bitsRight = *src++; \
	bits = (FbStipLeft (bitsLeft, leftShift) | \
		FbStipRight(bitsRight, rightShift)); \
	bitsLeft = bitsRight; \
    } else \
	bits = *src++; \
}

#ifndef FBNOPIXADDR

#define LaneCases1(n,a)	    case n: (void)FbLaneCase(n,a); break
#define LaneCases2(n,a)	    LaneCases1(n,a); LaneCases1(n+1,a)
#define LaneCases4(n,a)	    LaneCases2(n,a); LaneCases2(n+2,a)
#define LaneCases8(n,a)	    LaneCases4(n,a); LaneCases4(n+4,a)
#define LaneCases16(n,a)    LaneCases8(n,a); LaneCases8(n+8,a)
#define LaneCases32(n,a)    LaneCases16(n,a); LaneCases16(n+16,a)
#define LaneCases64(n,a)    LaneCases32(n,a); LaneCases32(n+32,a)
#define LaneCases128(n,a)   LaneCases64(n,a); LaneCases64(n+64,a)
#define LaneCases256(n,a)   LaneCases128(n,a); LaneCases128(n+128,a)

#if FB_SHIFT == 6
#define LaneCases(a)	    LaneCases256(0,a)
#endif

#if FB_SHIFT == 5
#define LaneCases(a)	    LaneCases16(0,a)
#endif

#if FB_SHIFT == 6
static uint8_t const fb8Lane[256] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78,
79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
98, 99, 100, 101, 102,103,104,105,106,107,108,109,110,111,112,113,114,115,
116, 117, 118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,
134, 135, 136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,
152, 153, 154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,
170, 171, 172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,
188, 189, 190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,
206, 207, 208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
224, 225, 226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,
242, 243, 244,245,246,247,248,249,250,251,252,253,254,255,
};

static uint8_t const fb16Lane[256] = {
    0x00, 0x03, 0x0c, 0x0f,
    0x30, 0x33, 0x3c, 0x3f,
    0xc0, 0xc3, 0xcc, 0xcf,
    0xf0, 0xf3, 0xfc, 0xff,
};

static uint8_t const fb32Lane[16] = {
    0x00, 0x0f, 0xf0, 0xff,
};
#endif

#if FB_SHIFT == 5
static uint8_t const fb8Lane[16] = {
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
};

static uint8_t const fb16Lane[16] = {
    0, 3, 12, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};

static uint8_t const fb32Lane[16] = {
    0, 15,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
#endif

static const uint8_t *
fbLaneTable(int bpp)
{
    switch (bpp) {
    case 8:
	return fb8Lane;
    case 16:
	return fb16Lane;
    case 32:
	return fb32Lane;
    }
    return NULL;
}
#endif

void
fbBltOne (FbStip    *src,
	  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)
{
    const FbBits    *fbBits;
    int		    pixelsPerDst;		/* dst pixels per FbBits */
    int		    unitsPerSrc;		/* src patterns per FbStip */
    int		    leftShift, rightShift;	/* align source with dest */
    FbBits	    startmask, endmask;		/* dest scanline masks */
    FbStip	    bits=0, bitsLeft, bitsRight;/* source bits */
    FbStip	    left;
    FbBits	    mask;
    int		    nDst;			/* dest longwords (w.o. end) */
    int		    w;
    int		    n, nmiddle;
    int		    dstS;			/* stipple-relative dst X coordinate */
    Bool	    copy;			/* accelerate dest-invariant */
    Bool	    transparent;		/* accelerate 0 nop */
    int		    srcinc;			/* source units consumed */
    Bool	    endNeedsLoad = FALSE;	/* need load for endmask */
#ifndef FBNOPIXADDR
    const CARD8	    *fbLane;
#endif
    int		    startbyte, endbyte;

#ifdef FB_24BIT
    if (dstBpp == 24)
    {
	fbBltOne24 (src, srcStride, srcX,
		    dst, dstStride, dstX, dstBpp,
		    width, height,
		    fgand, fgxor, bgand, bgxor);
	return;
    }
#endif

    /*
     * Number of destination units in FbBits == number of stipple pixels
     * used each time
     */
    pixelsPerDst = FB_UNIT / dstBpp;

    /*
     * Number of source stipple patterns in FbStip
     */
    unitsPerSrc = FB_STIP_UNIT / pixelsPerDst;

    copy = FALSE;
    transparent = FALSE;
    if (bgand == 0 && fgand == 0)
	copy = TRUE;
    else if (bgand == FB_ALLONES && bgxor == 0)
	transparent = TRUE;

    /*
     * Adjust source and dest to nearest FbBits boundary
     */
    src += srcX >> FB_STIP_SHIFT;
    dst += dstX >> FB_SHIFT;
    srcX &= FB_STIP_MASK;
    dstX &= FB_MASK;

    FbMaskBitsBytes(dstX, width, copy,
		    startmask, startbyte, nmiddle, endmask, endbyte);

    /*
     * Compute effective dest alignment requirement for
     * source -- must align source to dest unit boundary
     */
    dstS = dstX / dstBpp;
    /*
     * Compute shift constants for effective alignement
     */
    if (srcX >= dstS)
    {
	leftShift = srcX - dstS;
	rightShift = FB_STIP_UNIT - leftShift;
    }
    else
    {
	rightShift = dstS - srcX;
	leftShift = FB_STIP_UNIT - rightShift;
    }
    /*
     * Get pointer to stipple mask array for this depth
     */
    fbBits = NULL;	/* unused */
    if (pixelsPerDst <= 8)
	fbBits = fbStippleTable(pixelsPerDst);
#ifndef FBNOPIXADDR
    fbLane = NULL;
    if (transparent && fgand == 0 && dstBpp >= 8)
	fbLane = fbLaneTable(dstBpp);
#endif

    /*
     * Compute total number of destination words written, but
     * don't count endmask
     */
    nDst = nmiddle;
    if (startmask)
	nDst++;

    dstStride -= nDst;

    /*
     * Compute total number of source words consumed
     */

    srcinc = (nDst + unitsPerSrc - 1) / unitsPerSrc;

    if (srcX > dstS)
	srcinc++;
    if (endmask)
    {
	endNeedsLoad = nDst % unitsPerSrc == 0;
	if (endNeedsLoad)
	    srcinc++;
    }

    srcStride -= srcinc;

    /*
     * Copy rectangle
     */
    while (height--)
    {
	w = nDst;	    /* total units across scanline */
	n = unitsPerSrc;    /* units avail in single stipple */
	if (n > w)
	    n = w;

	bitsLeft = 0;
	if (srcX > dstS)
	    bitsLeft = *src++;
	if (n)
	{
	    /*
	     * Load first set of stipple bits
	     */
	    LoadBits;

	    /*
	     * Consume stipple bits for startmask
	     */
	    if (startmask)
	    {
#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 & startmask, fgxor, 1);
		}
		else
#endif
		{
		    if (mask || !transparent)
			FbDoLeftMaskByteStippleRRop (dst, mask,
						     fgand, fgxor, bgand, bgxor,
						     startbyte, startmask);
		}
		bits = FbStipLeft (bits, pixelsPerDst);
		dst++;
		n--;
		w--;
	    }
	    /*
	     * Consume stipple bits across scanline
	     */
	    for (;;)
	    {
		w -= n;
		if (copy)
		{
		    while (n--)
		    {
#if FB_UNIT > 32
			if (pixelsPerDst == 16)
			    mask = FbStipple16Bits(FbLeftStipBits(bits,16));
			else
#endif
			    mask = fbBits[FbLeftStipBits(bits,pixelsPerDst)];
			*dst = FbOpaqueStipple (mask, fgxor, bgxor);
			dst++;
			bits = FbStipLeft(bits, pixelsPerDst);
		    }
		}
		else
		{
#ifndef FBNOPIXADDR
		    if (fbLane)
		    {
			while (bits && n)
			{
			    switch (fbLane[FbLeftStipBits(bits,pixelsPerDst)]) {
				LaneCases((CARD8 *) dst);
			    }
			    bits = FbStipLeft(bits,pixelsPerDst);
			    dst++;
			    n--;
			}
			dst += n;
		    }
		    else
#endif
		    {
			while (n--)
			{
			    left = FbLeftStipBits(bits,pixelsPerDst);
			    if (left || !transparent)
			    {
				mask = fbBits[left];
				*dst = FbStippleRRop (*dst, mask,
						      fgand, fgxor, bgand, bgxor);
			    }
			    dst++;
			    bits = FbStipLeft(bits, pixelsPerDst);