cfbline.c

早期freebsd实现

	    	    clip1 = 0;
	    	    clip2 = 0;
    	
		    if (mfbClipLine (pbox, box,
				     &pt1, &pt1Copy, &pt2Copy, 
				     adx, ady, signdx, signdy, axis,
				     &clip1, &clip2) == 1)
		    {
		    	if (axis == X_AXIS)
			    len = abs(pt2Copy.x - pt1Copy.x);
		    	else
			    len = abs(pt2Copy.y - pt1Copy.y);
    
#ifdef POLYSEGMENT
		    	if (clip2 != 0 || pGC->capStyle != CapNotLast)
			    len++;
#else
		    	len += (clip2 != 0);
#endif
		    	if (len)
		    	{
			    /* unwind bresenham error term to first point */
			    if (clip1)
			    {
			    	clipdx = abs(pt1Copy.x - x1);
			    	clipdy = abs(pt1Copy.y - y1);
			    	if (axis == X_AXIS)
				    err = e+((clipdy*e2) + ((clipdx-clipdy)*e1));
			    	else
				    err = e+((clipdx*e2) + ((clipdy-clipdx)*e1));
			    }
			    else
			    	err = e;
			    cfbBresS   
				     (alu, and, xor,
				      addrl, nlwidth,
				      signdx, signdy, axis, pt1Copy.x, pt1Copy.y,
				      err, e1, e2, len);
		    	}
		    }
		    pbox++;
		}
	    } /* while (nbox--) */
	} /* sloped line */
    } /* while (nline--) */

#ifndef POLYSEGMENT
    /* paint the last point if the end style isn't CapNotLast.
       (Assume that a projecting, butt, or round cap that is one
        pixel wide is the same as the single pixel of the endpoint.)
    */

    if ((pGC->capStyle != CapNotLast) &&
	((ppt->x + xorg != pptInit->x + pDrawable->x) ||
	 (ppt->y + yorg != pptInit->y + pDrawable->y) ||
	 (ppt == pptInit + 1)))
    {
	nbox = nboxInit;
	pbox = pboxInit;
	while (nbox--)
	{
	    if ((x2 >= pbox->x1) &&
		(y2 >= pbox->y1) &&
		(x2 <  pbox->x2) &&
		(y2 <  pbox->y2))
	    {
		unsigned long mask;
		unsigned long scrbits;

		mask = cfbmask[x2 & PIM];
		addrl += (y2 * nlwidth) + (x2 >> PWSH);
		scrbits = *addrl;
		*addrl = (scrbits & ~mask) |
			 (DoRRop (scrbits, and, xor) & mask);
		break;
	    }
	    else
		pbox++;
	}
    }
#endif
}

/*
 * Draw dashed 1-pixel lines.
 */

void
#ifdef POLYSEGMENT
cfbSegmentSD (pDrawable, pGC, nseg, pSeg)
    DrawablePtr	pDrawable;
    register GCPtr	pGC;
    int		nseg;
    register xSegment	*pSeg;
#else
cfbLineSD( pDrawable, pGC, mode, npt, pptInit)
    DrawablePtr pDrawable;
    register GCPtr pGC;
    int mode;		/* Origin or Previous */
    int npt;		/* number of points */
    DDXPointPtr pptInit;
#endif
{
    int nboxInit;
    register int nbox;
    BoxPtr pboxInit;
    register BoxPtr pbox;
#ifndef POLYSEGMENT
    register DDXPointPtr ppt;	/* pointer to list of translated points */
#endif

    register unsigned int oc1;		/* outcode of point 1 */
    register unsigned int oc2;		/* outcode of point 2 */

    unsigned long *addrl;		/* address of destination pixmap */
    int nlwidth;		/* width in longwords of destination pixmap */
    int xorg, yorg;		/* origin of window */

    int adx;		/* abs values of dx and dy */
    int ady;
    int signdx;		/* sign of dx and dy */
    int signdy;
    int e, e1, e2;		/* bresenham error and increments */
    int len;			/* length of segment */
    int axis;			/* major axis */
    int x1, x2, y1, y2;
    RegionPtr cclip;
    cfbRRopRec	    rrops[2];
    unsigned char   *pDash;
    int		    dashOffset;
    int		    numInDashList;
    int		    dashIndex;
    int		    isDoubleDash;
    int		    dashIndexTmp, dashOffsetTmp;
    int		    unclippedlen;
    cfbPrivGCPtr    devPriv;

    devPriv = (cfbPrivGC *)(pGC->devPrivates[cfbGCPrivateIndex].ptr); 
    cclip = devPriv->pCompositeClip;
    rrops[0].rop = devPriv->rop;
    rrops[0].and = devPriv->and;
    rrops[0].xor = devPriv->xor;
    if (pGC->alu == GXcopy)
    {
	rrops[1].rop = GXcopy;
	rrops[1].and = 0;
	rrops[1].xor = PFILL (pGC->bgPixel);
    }
    else
    {
    	rrops[1].rop = cfbReduceRasterOp (pGC->alu,
					  pGC->bgPixel, pGC->planemask,
					  &rrops[1].and, &rrops[1].xor);
    }
    pboxInit = REGION_RECTS(cclip);
    nboxInit = REGION_NUM_RECTS(cclip);

    cfbGetLongWidthAndPointer (pDrawable, nlwidth, addrl)

    SET_REGISTERS_FOR_WRITING(pDrawable->pScreen, ~0, GXcopy);

    /* compute initial dash values */
     
    pDash = (unsigned char *) pGC->dash;
    numInDashList = pGC->numInDashList;
    isDoubleDash = (pGC->lineStyle == LineDoubleDash);
    dashIndex = 0;
    dashOffset = 0;
    miStepDash ((int)pGC->dashOffset, &dashIndex, pDash,
		numInDashList, &dashOffset);

    xorg = pDrawable->x;
    yorg = pDrawable->y;
#ifdef POLYSEGMENT
    while (nseg--)
#else
    ppt = pptInit;
    x2 = ppt->x + xorg;
    y2 = ppt->y + yorg;
    while(--npt)
#endif
    {
	nbox = nboxInit;
	pbox = pboxInit;

#ifdef POLYSEGMENT
	x1 = pSeg->x1 + xorg;
	y1 = pSeg->y1 + yorg;
	x2 = pSeg->x2 + xorg;
	y2 = pSeg->y2 + yorg;
	pSeg++;
#else
	x1 = x2;
	y1 = y2;
	++ppt;
	if (mode == CoordModePrevious)
	{
	    xorg = x1;
	    yorg = y1;
	}
	x2 = ppt->x + xorg;
	y2 = ppt->y + yorg;
#endif

	adx = x2 - x1;
	ady = y2 - y1;
	signdx = sign(adx);
	signdy = sign(ady);
	adx = abs(adx);
	ady = abs(ady);

	if (adx > ady)
	{
	    axis = X_AXIS;
	    e1 = ady << 1;
	    e2 = e1 - (adx << 1);
	    e = e1 - adx;
	    unclippedlen = adx;
	}
	else
	{
	    axis = Y_AXIS;
	    e1 = adx << 1;
	    e2 = e1 - (ady << 1);
	    e = e1 - ady;
	    unclippedlen = ady;
	}

	/* we have bresenham parameters and two points.
	   all we have to do now is clip and draw.
	*/

	while(nbox--)
	{
	    oc1 = 0;
	    oc2 = 0;
	    OUTCODES(oc1, x1, y1, pbox);
	    OUTCODES(oc2, x2, y2, pbox);
	    if ((oc1 | oc2) == 0)
	    {
#ifdef POLYSEGMENT
		if (pGC->capStyle != CapNotLast)
		    unclippedlen++;
		dashIndexTmp = dashIndex;
		dashOffsetTmp = dashOffset;
		cfbBresD (rrops,
		      &dashIndexTmp, pDash, numInDashList,
		      &dashOffsetTmp, isDoubleDash,
		      addrl, nlwidth,
		      signdx, signdy, axis, x1, y1,
		      e, e1, e2, unclippedlen);
		break;
#else
		cfbBresD (rrops,
		      &dashIndex, pDash, numInDashList,
		      &dashOffset, isDoubleDash,
		      addrl, nlwidth,
		      signdx, signdy, axis, x1, y1,
		      e, e1, e2, unclippedlen);
		goto dontStep;
#endif
	    }
	    else if (oc1 & oc2)
	    {
		pbox++;
	    }
	    else /* have to clip */
	    {
		/*
		 * let the mfb helper routine do our work;
		 * better than duplicating code...
		 */
		BoxRec box;
		DDXPointRec pt1Copy;	/* clipped start point */
		DDXPointRec pt2Copy;	/* clipped end point */
		int err;			/* modified bresenham error term */
		int clip1, clip2;		/* clippedness of the endpoints */
	    
		int clipdx, clipdy;		/* difference between clipped and
					       unclipped start point */
		DDXPointRec	pt1;
    
		pt1.x = pt1Copy.x = x1;
		pt1.y = pt1Copy.y = y1;
		pt2Copy.x = x2;
		pt2Copy.y = y2;
		box.x1 = pbox->x1;
		box.y1 = pbox->y1;
		box.x2 = pbox->x2-1;
		box.y2 = pbox->y2-1;
		clip1 = 0;
		clip2 = 0;
    
		if (mfbClipLine (pbox, box,
				       &pt1, &pt1Copy, &pt2Copy, 
				       adx, ady, signdx, signdy, axis,
				       &clip1, &clip2) == 1)
		{
    
		    dashIndexTmp = dashIndex;
		    dashOffsetTmp = dashOffset;
		    if (clip1)
		    {
		    	int dlen;
    
		    	if (axis == X_AXIS)
			    dlen = abs(pt1Copy.x - x1);
		    	else
			    dlen = abs(pt1Copy.y - y1);
		    	miStepDash (dlen, &dashIndexTmp, pDash,
				    numInDashList, &dashOffsetTmp);
		    }
		    if (axis == X_AXIS)
		    	len = abs(pt2Copy.x - pt1Copy.x);
		    else
		    	len = abs(pt2Copy.y - pt1Copy.y);
    
#ifdef POLYSEGMENT
		    if (clip2 != 0 || pGC->capStyle != CapNotLast)
		    	len++;
#else
		    len += (clip2 != 0);
#endif
		    if (len)
		    {
		    	/* unwind bresenham error term to first point */
		    	if (clip1)
		    	{
			    clipdx = abs(pt1Copy.x - x1);
			    clipdy = abs(pt1Copy.y - y1);
			    if (axis == X_AXIS)
			    	err = e+((clipdy*e2) + ((clipdx-clipdy)*e1));
			    else
			    	err = e+((clipdx*e2) + ((clipdy-clipdx)*e1));
		    	}
		    	else
			    err = e;
		    	cfbBresD (rrops,
			      	  &dashIndexTmp, pDash, numInDashList,
			      	  &dashOffsetTmp, isDoubleDash,
			      	  addrl, nlwidth,
			      	  signdx, signdy, axis, pt1Copy.x, pt1Copy.y,
			      	  err, e1, e2, len);
		    }
		}
		pbox++;
	    }
	} /* while (nbox--) */
#ifndef POLYSEGMENT
	/*
	 * walk the dash list around to the next line
	 */
	miStepDash (unclippedlen, &dashIndex, pDash,
		    numInDashList, &dashOffset);
dontStep:	;
#endif
    } /* while (nline--) */

#ifndef POLYSEGMENT
    /* paint the last point if the end style isn't CapNotLast.
       (Assume that a projecting, butt, or round cap that is one
        pixel wide is the same as the single pixel of the endpoint.)
    */

    if ((pGC->capStyle != CapNotLast) &&
        ((dashIndex & 1) == 0 || isDoubleDash) &&
	((ppt->x + xorg != pptInit->x + pDrawable->x) ||
	 (ppt->y + yorg != pptInit->y + pDrawable->y) ||
	 (ppt == pptInit + 1)))
    {
	nbox = nboxInit;
	pbox = pboxInit;
	while (nbox--)
	{
	    if ((x2 >= pbox->x1) &&
		(y2 >= pbox->y1) &&
		(x2 <  pbox->x2) &&
		(y2 <  pbox->y2))
	    {
		unsigned long	mask;
		int		pix;

		pix = 0;
		if (dashIndex & 1)
		    pix = 1;
		mask = cfbmask[x2 & PIM];
		addrl += (y2 * nlwidth) + (x2 >> PWSH);
		*addrl = DoMaskRRop (*addrl, rrops[pix].and, rrops[pix].xor, mask);
		break;
	    }
	    else
		pbox++;
	}
    }
#endif
}