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+/***********************************************************
+
+Copyright 1987, 1998 The Open Group
+
+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.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+
+Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
+
+ All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+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 Digital not be
+used in advertising or publicity pertaining to distribution of the
+software without specific, written prior permission.
+
+DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
+ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
+DIGITAL 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.
+
+******************************************************************/
+/* $Xorg: mfbline.c,v 1.4 2001/02/09 02:05:19 xorgcvs Exp $ */
+#include "X.h"
+
+#include "gcstruct.h"
+#include "windowstr.h"
+#include "pixmapstr.h"
+#include "regionstr.h"
+#include "scrnintstr.h"
+#include "mistruct.h"
+
+#include "mfb.h"
+#include "maskbits.h"
+#include "miline.h"
+
+/* single-pixel lines on a color frame buffer
+
+ NON-SLOPED LINES
+ horizontal lines are always drawn left to right; we have to
+move the endpoints right by one after they're swapped.
+ horizontal lines will be confined to a single band of a
+region. the code finds that band (giving up if the lower
+bound of the band is above the line we're drawing); then it
+finds the first box in that band that contains part of the
+line. we clip the line to subsequent boxes in that band.
+ vertical lines are always drawn top to bottom (y-increasing.)
+this requires adding one to the y-coordinate of each endpoint
+after swapping.
+
+ SLOPED LINES
+ when clipping a sloped line, we bring the second point inside
+the clipping box, rather than one beyond it, and then add 1 to
+the length of the line before drawing it. this lets us use
+the same box for finding the outcodes for both endpoints. since
+the equation for clipping the second endpoint to an edge gives us
+1 beyond the edge, we then have to move the point towards the
+first point by one step on the major axis.
+ eventually, there will be a diagram here to explain what's going
+on. the method uses Cohen-Sutherland outcodes to determine
+outsideness, and a method similar to Pike's layers for doing the
+actual clipping.
+
+*/
+
+void
+#ifdef POLYSEGMENT
+mfbSegmentSS (pDrawable, pGC, nseg, pSeg)
+ DrawablePtr pDrawable;
+ GCPtr pGC;
+ int nseg;
+ register xSegment *pSeg;
+#else
+mfbLineSS (pDrawable, pGC, mode, npt, pptInit)
+ DrawablePtr pDrawable;
+ 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
+
+ unsigned int oc1; /* outcode of point 1 */
+ unsigned int oc2; /* outcode of point 2 */
+
+ PixelType *addrlBase; /* pointer to start of drawable */
+ PixelType *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 octant;
+ unsigned int bias = miGetZeroLineBias(pDrawable->pScreen);
+
+ /* a bunch of temporaries */
+ register int y1, y2;
+ register int x1, x2;
+ RegionPtr cclip;
+ int alu;
+
+ if (!(pGC->planemask & 1))
+ return;
+
+ cclip = ((mfbPrivGC *)(pGC->devPrivates[mfbGCPrivateIndex].ptr))->pCompositeClip;
+ alu = ((mfbPrivGC *)(pGC->devPrivates[mfbGCPrivateIndex].ptr))->rop;
+ pboxInit = REGION_RECTS(cclip);
+ nboxInit = REGION_NUM_RECTS(cclip);
+
+ mfbGetPixelWidthAndPointer(pDrawable, nlwidth, addrlBase);
+
+ 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
+
+ if (x1 == x2) /* vertical line */
+ {
+ /* make the line go top to bottom of screen, keeping
+ endpoint semantics
+ */
+ if (y1 > y2)
+ {
+ register int tmp;
+
+ tmp = y2;
+ y2 = y1 + 1;
+ y1 = tmp + 1;
+#ifdef POLYSEGMENT
+ if (pGC->capStyle != CapNotLast)
+ y1--;
+#endif
+ }
+#ifdef POLYSEGMENT
+ else if (pGC->capStyle != CapNotLast)
+ y2++;
+#endif
+ /* get to first band that might contain part of line */
+ while ((nbox) && (pbox->y2 <= y1))
+ {
+ pbox++;
+ nbox--;
+ }
+
+ if (nbox)
+ {
+ /* stop when lower edge of box is beyond end of line */
+ while((nbox) && (y2 >= pbox->y1))
+ {
+ if ((x1 >= pbox->x1) && (x1 < pbox->x2))
+ {
+ int y1t, y2t;
+ /* this box has part of the line in it */
+ y1t = max(y1, pbox->y1);
+ y2t = min(y2, pbox->y2);
+ if (y1t != y2t)
+ {
+ mfbVertS (alu,
+ addrlBase, nlwidth,
+ x1, y1t, y2t-y1t);
+ }
+ }
+ nbox--;
+ pbox++;
+ }
+ }
+#ifndef POLYSEGMENT
+ y2 = ppt->y + yorg;
+#endif
+ }
+ else if (y1 == y2) /* horizontal line */
+ {
+ /* force line from left to right, keeping
+ endpoint semantics
+ */
+ if (x1 > x2)
+ {
+ register int tmp;
+
+ tmp = x2;
+ x2 = x1 + 1;
+ x1 = tmp + 1;
+#ifdef POLYSEGMENT
+ if (pGC->capStyle != CapNotLast)
+ x1--;
+#endif
+ }
+#ifdef POLYSEGMENT
+ else if (pGC->capStyle != CapNotLast)
+ x2++;
+#endif
+
+ /* find the correct band */
+ while( (nbox) && (pbox->y2 <= y1))
+ {
+ pbox++;
+ nbox--;
+ }
+
+ /* try to draw the line, if we haven't gone beyond it */
+ if ((nbox) && (pbox->y1 <= y1))
+ {
+ int tmp;
+
+ /* when we leave this band, we're done */
+ tmp = pbox->y1;
+ while((nbox) && (pbox->y1 == tmp))
+ {
+ int x1t, x2t;
+
+ if (pbox->x2 <= x1)
+ {
+ /* skip boxes until one might contain start point */
+ nbox--;
+ pbox++;
+ continue;
+ }
+
+ /* stop if left of box is beyond right of line */
+ if (pbox->x1 >= x2)
+ {
+ nbox = 0;
+ break;
+ }
+
+ x1t = max(x1, pbox->x1);
+ x2t = min(x2, pbox->x2);
+ if (x1t != x2t)
+ {
+ mfbHorzS (alu,
+ addrlBase, nlwidth,
+ x1t, y1, x2t-x1t);
+ }
+ nbox--;
+ pbox++;
+ }
+ }
+#ifndef POLYSEGMENT
+ x2 = ppt->x + xorg;
+#endif
+ }
+ else /* sloped line */
+ {
+ CalcLineDeltas(x1, y1, x2, y2, adx, ady, signdx, signdy,
+ 1, 1, octant);
+
+ if (adx > ady)
+ {
+ axis = X_AXIS;
+ e1 = ady << 1;
+ e2 = e1 - (adx << 1);
+ e = e1 - adx;
+ }
+ else
+ {
+ axis = Y_AXIS;
+ e1 = adx << 1;
+ e2 = e1 - (ady << 1);
+ e = e1 - ady;
+ SetYMajorOctant(octant);
+ }
+
+ FIXUP_ERROR(e, octant, bias);
+
+ /* 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)
+ {
+ if (axis == X_AXIS)
+ len = adx;
+ else
+ len = ady;
+#ifdef POLYSEGMENT
+ if (pGC->capStyle != CapNotLast)
+ len++;
+#endif
+ mfbBresS (alu,
+ addrlBase, nlwidth,
+ signdx, signdy, axis, x1, y1,
+ e, e1, e2, len);
+ break;
+ }
+ else if (oc1 & oc2)
+ {
+ pbox++;
+ }
+ else
+ {
+ int new_x1 = x1, new_y1 = y1, new_x2 = x2, new_y2 = y2;
+ int clip1 = 0, clip2 = 0;
+ int clipdx, clipdy;
+ int err;
+
+ if (miZeroClipLine(pbox->x1, pbox->y1, pbox->x2-1,
+ pbox->y2-1,
+ &new_x1, &new_y1, &new_x2, &new_y2,
+ adx, ady, &clip1, &clip2,
+ octant, bias, oc1, oc2) == -1)
+ {
+ pbox++;
+ continue;
+ }
+
+ if (axis == X_AXIS)
+ len = abs(new_x2 - new_x1);
+ else
+ len = abs(new_y2 - new_y1);
+#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(new_x1 - x1);
+ clipdy = abs(new_y1 - y1);
+ if (axis == X_AXIS)
+ err = e+((clipdy*e2) + ((clipdx-clipdy)*e1));
+ else
+ err = e+((clipdx*e2) + ((clipdy-clipdx)*e1));
+ }
+ else
+ err = e;
+ mfbBresS
+ (alu,
+ addrlBase, nlwidth,
+ signdx, signdy, axis, new_x1, new_y1,
+ 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)))
+ {
+ PixelType _mask;
+
+ if (alu == RROP_BLACK)
+ _mask = rmask[x2 & PIM];
+ else
+ _mask = mask[x2 & PIM];
+
+ nbox = nboxInit;
+ pbox = pboxInit;
+ while (nbox--)
+ {
+ if ((x2 >= pbox->x1) &&
+ (y2 >= pbox->y1) &&
+ (x2 < pbox->x2) &&
+ (y2 < pbox->y2))
+ {
+ addrl = mfbScanline(addrlBase, x2, y2, nlwidth);
+ switch(alu)
+ {
+ case RROP_BLACK:
+ *addrl &= _mask;
+ break;
+ case RROP_WHITE:
+ *addrl |= _mask;
+ break;
+ case RROP_INVERT:
+ *addrl ^= _mask;
+ break;
+ }
+ break;
+ }
+ else
+ pbox++;
+ }
+ }
+#endif
+}
+
+/*
+ * Draw dashed 1-pixel lines.
+ */
+
+void
+#ifdef POLYSEGMENT
+mfbSegmentSD (pDrawable, pGC, nseg, pSeg)
+ DrawablePtr pDrawable;
+ register GCPtr pGC;
+ int nseg;
+ register xSegment *pSeg;
+#else
+mfbLineSD( 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 */
+
+ PixelType *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 octant;
+ unsigned int bias = miGetZeroLineBias(pDrawable->pScreen);
+ int x1, x2, y1, y2;
+ RegionPtr cclip;
+ int fgrop, bgrop;
+ unsigned char *pDash;
+ int dashOffset;
+ int numInDashList;
+ int dashIndex;
+ int isDoubleDash;
+ int dashIndexTmp, dashOffsetTmp;
+ int unclippedlen;
+
+ if (!(pGC->planemask & 1))
+ return;
+
+ cclip = ((mfbPrivGC *)(pGC->devPrivates[mfbGCPrivateIndex].ptr))->pCompositeClip;
+ fgrop = ((mfbPrivGC *)(pGC->devPrivates[mfbGCPrivateIndex].ptr))->rop;
+ pboxInit = REGION_RECTS(cclip);
+ nboxInit = REGION_NUM_RECTS(cclip);
+
+ mfbGetPixelWidthAndPointer(pDrawable, nlwidth, addrl);
+
+ /* 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);
+
+ if (isDoubleDash)
+ bgrop = mfbReduceRop(pGC->alu, pGC->bgPixel);
+
+ 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
+
+ CalcLineDeltas(x1, y1, x2, y2, adx, ady, signdx, signdy, 1, 1, octant);
+
+ 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;
+ SetYMajorOctant(octant);
+ }
+
+ FIXUP_ERROR(e, octant, bias);
+
+ /* 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;
+ mfbBresD (fgrop, bgrop,
+ &dashIndexTmp, pDash, numInDashList,
+ &dashOffsetTmp, isDoubleDash,
+ addrl, nlwidth,
+ signdx, signdy, axis, x1, y1,
+ e, e1, e2, unclippedlen);
+ break;
+#else
+ mfbBresD (fgrop, bgrop,
+ &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 */
+ {
+ int new_x1 = x1, new_y1 = y1, new_x2 = x2, new_y2 = y2;
+ int clip1 = 0, clip2 = 0;
+ int clipdx, clipdy;
+ int err;
+
+ if (miZeroClipLine(pbox->x1, pbox->y1, pbox->x2-1, pbox->y2-1,
+ &new_x1, &new_y1, &new_x2, &new_y2,
+ adx, ady, &clip1, &clip2,
+ octant, bias, oc1, oc2) == -1)
+ {
+ pbox++;
+ continue;
+ }
+ dashIndexTmp = dashIndex;
+ dashOffsetTmp = dashOffset;
+ if (clip1)
+ {
+ int dlen;
+
+ if (axis == X_AXIS)
+ dlen = abs(new_x1 - x1);
+ else
+ dlen = abs(new_y1 - y1);
+ miStepDash (dlen, &dashIndexTmp, pDash,
+ numInDashList, &dashOffsetTmp);
+ }
+ if (axis == X_AXIS)
+ len = abs(new_x2 - new_x1);
+ else
+ len = abs(new_y2 - new_y1);
+#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(new_x1 - x1);
+ clipdy = abs(new_y1 - y1);
+ if (axis == X_AXIS)
+ err = e+((clipdy*e2) + ((clipdx-clipdy)*e1));
+ else
+ err = e+((clipdx*e2) + ((clipdy-clipdx)*e1));
+ }
+ else
+ err = e;
+ mfbBresD (fgrop, bgrop,
+ &dashIndexTmp, pDash, numInDashList,
+ &dashOffsetTmp, isDoubleDash,
+ addrl, nlwidth,
+ signdx, signdy, axis, new_x1, new_y1,
+ 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 rop;
+
+ rop = fgrop;
+ if (dashIndex & 1)
+ rop = bgrop;
+ if (rop == RROP_BLACK)
+ _mask = rmask[x2 & PIM];
+ else
+ _mask = mask[x2 & PIM];
+ addrl = mfbScanline(addrl, x2, y2, nlwidth);
+ if (rop == RROP_BLACK)
+ *addrl &= _mask;
+ else if (rop == RROP_WHITE)
+ *addrl |= _mask;
+ else
+ *addrl ^= _mask;
+ break;
+ }
+ else
+ pbox++;
+ }
+ }
+#endif
+}
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