xenocara/xserver/mi/miwideline.c

/*

Copyright 1988, 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.

*/

/* Author:  Keith Packard, MIT X Consortium */

/*
 * Mostly integer wideline code.  Uses a technique similar to
 * bresenham zero-width lines, except walks an X edge
 */

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <stdio.h>
#ifdef _XOPEN_SOURCE
#include <math.h>
#else
#define _XOPEN_SOURCE           /* to get prototype for hypot on some systems */
#include <math.h>
#undef _XOPEN_SOURCE
#endif
#include <X11/X.h>
#include "windowstr.h"
#include "gcstruct.h"
#include "regionstr.h"
#include "miwideline.h"
#include "mi.h"

static Bool
InitSpans(Spans * spans, size_t nspans)
{
    spans->points = malloc(nspans * sizeof(*spans->points));
    if (!spans->points)
        return FALSE;
    spans->widths = malloc(nspans * sizeof(*spans->widths));
    if (!spans->widths) {
        free(spans->points);
        return FALSE;
    }
    return TRUE;
}

/*
 * interface data to span-merging polygon filler
 */

typedef struct _SpanData {
    SpanGroup fgGroup, bgGroup;
} SpanDataRec, *SpanDataPtr;

static void
AppendSpanGroup(GCPtr pGC, unsigned long pixel, Spans * spanPtr,
                SpanDataPtr spanData)
{
    SpanGroup *group, *othergroup = NULL;

    if (pixel == pGC->fgPixel) {
        group = &spanData->fgGroup;
        if (pGC->lineStyle == LineDoubleDash)
            othergroup = &spanData->bgGroup;
    }
    else {
        group = &spanData->bgGroup;
        othergroup = &spanData->fgGroup;
    }
    miAppendSpans(group, othergroup, spanPtr);
}

static void miLineArc(DrawablePtr pDraw, GCPtr pGC,
                      unsigned long pixel, SpanDataPtr spanData,
                      LineFacePtr leftFace,
                      LineFacePtr rightFace,
                      double xorg, double yorg, Bool isInt);

/*
 * spans-based polygon filler
 */

static void
fillSpans(DrawablePtr pDrawable, GCPtr pGC, unsigned long pixel, Spans * spans,
          SpanDataPtr spanData)
{
    if (!spanData) {
        ChangeGCVal oldPixel, tmpPixel;

        oldPixel.val = pGC->fgPixel;
        if (pixel != oldPixel.val) {
            tmpPixel.val = (XID) pixel;
            ChangeGC(NullClient, pGC, GCForeground, &tmpPixel);
            ValidateGC(pDrawable, pGC);
        }
        (*pGC->ops->FillSpans) (pDrawable, pGC, spans->count, spans->points,
                                spans->widths, TRUE);
        free(spans->widths);
        free(spans->points);
        if (pixel != oldPixel.val) {
            ChangeGC(NullClient, pGC, GCForeground, &oldPixel);
            ValidateGC(pDrawable, pGC);
        }
    }
    else
        AppendSpanGroup(pGC, pixel, spans, spanData);
}

static void
miFillPolyHelper(DrawablePtr pDrawable, GCPtr pGC, unsigned long pixel,
                 SpanDataPtr spanData, int y, int overall_height,
                 PolyEdgePtr left, PolyEdgePtr right,
                 int left_count, int right_count)
{
    int left_x = 0, left_e = 0;
    int left_stepx = 0;
    int left_signdx = 0;
    int left_dy = 0, left_dx = 0;

    int right_x = 0, right_e = 0;
    int right_stepx = 0;
    int right_signdx = 0;
    int right_dy = 0, right_dx = 0;

    int height = 0;
    int left_height = 0, right_height = 0;

    DDXPointPtr ppt;
    int *pwidth;
    int xorg;
    Spans spanRec;

    if (!InitSpans(&spanRec, overall_height))
        return;
    ppt = spanRec.points;
    pwidth = spanRec.widths;

    xorg = 0;
    if (pGC->miTranslate) {
        y += pDrawable->y;
        xorg = pDrawable->x;
    }
    while ((left_count || left_height) && (right_count || right_height)) {
        if (!left_height && left_count) {
            left_height = left->height;
            left_x = left->x;
            left_stepx = left->stepx;
            left_signdx = left->signdx;
            left_e = left->e;
            left_dy = left->dy;
            left_dx = left->dx;
            --left_count;
            ++left;
        }

        if (!right_height && right_count) {
            right_height = right->height;
            right_x = right->x;
            right_stepx = right->stepx;
            right_signdx = right->signdx;
            right_e = right->e;
            right_dy = right->dy;
            right_dx = right->dx;
            --right_count;
            ++right;
        }

        height = left_height;
        if (height > right_height)
            height = right_height;

        left_height -= height;
        right_height -= height;

        while (--height >= 0) {
            if (right_x >= left_x) {
                ppt->y = y;
                ppt->x = left_x + xorg;
                ppt++;
                *pwidth++ = right_x - left_x + 1;
            }
            y++;

            left_x += left_stepx;
            left_e += left_dx;
            if (left_e > 0) {
                left_x += left_signdx;
                left_e -= left_dy;
            }

            right_x += right_stepx;
            right_e += right_dx;
            if (right_e > 0) {
                right_x += right_signdx;
                right_e -= right_dy;
            }
        }
    }
    spanRec.count = ppt - spanRec.points;
    fillSpans(pDrawable, pGC, pixel, &spanRec, spanData);
}

static void
miFillRectPolyHelper(DrawablePtr pDrawable,
                     GCPtr pGC,
                     unsigned long pixel,
                     SpanDataPtr spanData, int x, int y, int w, int h)
{
    DDXPointPtr ppt;
    int *pwidth;
    ChangeGCVal oldPixel, tmpPixel;
    Spans spanRec;
    xRectangle rect;

    if (!spanData) {
        rect.x = x;
        rect.y = y;
        rect.width = w;
        rect.height = h;
        oldPixel.val = pGC->fgPixel;
        if (pixel != oldPixel.val) {
            tmpPixel.val = (XID) pixel;
            ChangeGC(NullClient, pGC, GCForeground, &tmpPixel);
            ValidateGC(pDrawable, pGC);
        }
        (*pGC->ops->PolyFillRect) (pDrawable, pGC, 1, &rect);
        if (pixel != oldPixel.val) {
            ChangeGC(NullClient, pGC, GCForeground, &oldPixel);
            ValidateGC(pDrawable, pGC);
        }
    }
    else {
        if (!InitSpans(&spanRec, h))
            return;
        ppt = spanRec.points;
        pwidth = spanRec.widths;

        if (pGC->miTranslate) {
            y += pDrawable->y;
            x += pDrawable->x;
        }
        while (h--) {
            ppt->x = x;
            ppt->y = y;
            ppt++;
            *pwidth++ = w;
            y++;
        }
        spanRec.count = ppt - spanRec.points;
        AppendSpanGroup(pGC, pixel, &spanRec, spanData);
    }
}

/* static */ int
miPolyBuildEdge(double x0, double y0, double k, /* x0 * dy - y0 * dx */
                int dx, int dy, int xi, int yi, int left, PolyEdgePtr edge)
{
    int x, y, e;
    int xady;

    if (dy < 0) {
        dy = -dy;
        dx = -dx;
        k = -k;
    }

#ifdef NOTDEF
    {
        double realk, kerror;

        realk = x0 * dy - y0 * dx;
        kerror = fabs(realk - k);
        if (kerror > .1)
            printf("realk: %g k: %g\n", realk, k);
    }
#endif
    y = ICEIL(y0);
    xady = ICEIL(k) + y * dx;

    if (xady <= 0)
        x = -(-xady / dy) - 1;
    else
        x = (xady - 1) / dy;

    e = xady - x * dy;

    if (dx >= 0) {
        edge->signdx = 1;
        edge->stepx = dx / dy;
        edge->dx = dx % dy;
    }
    else {
        edge->signdx = -1;
        edge->stepx = -(-dx / dy);
        edge->dx = -dx % dy;
        e = dy - e + 1;
    }
    edge->dy = dy;
    edge->x = x + left + xi;
    edge->e = e - dy;           /* bias to compare against 0 instead of dy */
    return y + yi;
}

#define StepAround(v, incr, max) (((v) + (incr) < 0) ? (max - 1) : ((v) + (incr) == max) ? 0 : ((v) + (incr)))

/* static */ int
miPolyBuildPoly(PolyVertexPtr vertices,
                PolySlopePtr slopes,
                int count,
                int xi,
                int yi,
                PolyEdgePtr left,
                PolyEdgePtr right, int *pnleft, int *pnright, int *h)
{
    int top, bottom;
    double miny, maxy;
    int i;
    int j;
    int clockwise;
    int slopeoff;
    int s;
    int nright, nleft;
    int y, lasty = 0, bottomy, topy = 0;

    /* find the top of the polygon */
    maxy = miny = vertices[0].y;
    bottom = top = 0;
    for (i = 1; i < count; i++) {
        if (vertices[i].y < miny) {
            top = i;
            miny = vertices[i].y;
        }
        if (vertices[i].y >= maxy) {
            bottom = i;
            maxy = vertices[i].y;
        }
    }
    clockwise = 1;
    slopeoff = 0;

    i = top;
    j = StepAround(top, -1, count);

    if ((int64_t) slopes[j].dy * slopes[i].dx >
        (int64_t) slopes[i].dy * slopes[j].dx) {
        clockwise = -1;
        slopeoff = -1;
    }

    bottomy = ICEIL(maxy) + yi;

    nright = 0;

    s = StepAround(top, slopeoff, count);
    i = top;
    while (i != bottom) {
        if (slopes[s].dy != 0) {
            y = miPolyBuildEdge(vertices[i].x, vertices[i].y,
                                slopes[s].k,
                                slopes[s].dx, slopes[s].dy,
                                xi, yi, 0, &right[nright]);
            if (nright != 0)
                right[nright - 1].height = y - lasty;
            else
                topy = y;
            nright++;
            lasty = y;
        }

        i = StepAround(i, clockwise, count);
        s = StepAround(s, clockwise, count);
    }
    if (nright != 0)
        right[nright - 1].height = bottomy - lasty;

    if (slopeoff == 0)
        slopeoff = -1;
    else
        slopeoff = 0;

    nleft = 0;
    s = StepAround(top, slopeoff, count);
    i = top;
    while (i != bottom) {
        if (slopes[s].dy != 0) {
            y = miPolyBuildEdge(vertices[i].x, vertices[i].y,
                                slopes[s].k,
                                slopes[s].dx, slopes[s].dy, xi, yi, 1,
                                &left[nleft]);

            if (nleft != 0)
                left[nleft - 1].height = y - lasty;
            nleft++;
            lasty = y;
        }
        i = StepAround(i, -clockwise, count);
        s = StepAround(s, -clockwise, count);
    }
    if (nleft != 0)
        left[nleft - 1].height = bottomy - lasty;
    *pnleft = nleft;
    *pnright = nright;
    *h = bottomy - topy;
    return topy;
}

static void
miLineOnePoint(DrawablePtr pDrawable,
               GCPtr pGC,
               unsigned long pixel, SpanDataPtr spanData, int x, int y)
{
    DDXPointRec pt;
    int wid;
    unsigned long oldPixel;

    MILINESETPIXEL(pDrawable, pGC, pixel, oldPixel);
    if (pGC->fillStyle == FillSolid) {
        pt.x = x;
        pt.y = y;
        (*pGC->ops->PolyPoint) (pDrawable, pGC, CoordModeOrigin, 1, &pt);
    }
    else {
        wid = 1;
        if (pGC->miTranslate) {
            x += pDrawable->x;
            y += pDrawable->y;
        }
        pt.x = x;
        pt.y = y;
        (*pGC->ops->FillSpans) (pDrawable, pGC, 1, &pt, &wid, TRUE);
    }
    MILINERESETPIXEL(pDrawable, pGC, pixel, oldPixel);
}

static void
miLineJoin(DrawablePtr pDrawable,
           GCPtr pGC,
           unsigned long pixel,
           SpanDataPtr spanData, LineFacePtr pLeft, LineFacePtr pRight)
{
    double mx = 0, my = 0;
    double denom = 0.0;
    PolyVertexRec vertices[4];
    PolySlopeRec slopes[4];
    int edgecount;
    PolyEdgeRec left[4], right[4];
    int nleft, nright;
    int y, height;
    int swapslopes;
    int joinStyle = pGC->joinStyle;
    int lw = pGC->lineWidth;

    if (lw == 1 && !spanData) {
        /* See if one of the lines will draw the joining pixel */
        if (pLeft->dx > 0 || (pLeft->dx == 0 && pLeft->dy > 0))
            return;
        if (pRight->dx > 0 || (pRight->dx == 0 && pRight->dy > 0))
            return;
        if (joinStyle != JoinRound) {
            denom =
                -pLeft->dx * (double) pRight->dy +
                pRight->dx * (double) pLeft->dy;
            if (denom == 0)
                return;         /* no join to draw */
        }
        if (joinStyle != JoinMiter) {
            miLineOnePoint(pDrawable, pGC, pixel, spanData, pLeft->x, pLeft->y);
            return;
        }
    }
    else {
        if (joinStyle == JoinRound) {
            miLineArc(pDrawable, pGC, pixel, spanData,
                      pLeft, pRight, (double) 0.0, (double) 0.0, TRUE);
            return;
        }
        denom =
            -pLeft->dx * (double) pRight->dy + pRight->dx * (double) pLeft->dy;
        if (denom == 0.0)
            return;             /* no join to draw */
    }

    swapslopes = 0;
    if (denom > 0) {
        pLeft->xa = -pLeft->xa;
        pLeft->ya = -pLeft->ya;
        pLeft->dx = -pLeft->dx;
        pLeft->dy = -pLeft->dy;
    }
    else {
        swapslopes = 1;
        pRight->xa = -pRight->xa;
        pRight->ya = -pRight->ya;
        pRight->dx = -pRight->dx;
        pRight->dy = -pRight->dy;
    }

    vertices[0].x = pRight->xa;
    vertices[0].y = pRight->ya;
    slopes[0].dx = -pRight->dy;
    slopes[0].dy = pRight->dx;
    slopes[0].k = 0;

    vertices[1].x = 0;
    vertices[1].y = 0;
    slopes[1].dx = pLeft->dy;
    slopes[1].dy = -pLeft->dx;
    slopes[1].k = 0;

    vertices[2].x = pLeft->xa;
    vertices[2].y = pLeft->ya;

    if (joinStyle == JoinMiter) {
        my = (pLeft->dy * (pRight->xa * pRight->dy - pRight->ya * pRight->dx) -
              pRight->dy * (pLeft->xa * pLeft->dy - pLeft->ya * pLeft->dx)) /
            denom;
        if (pLeft->dy != 0) {
            mx = pLeft->xa + (my - pLeft->ya) *
                (double) pLeft->dx / (double) pLeft->dy;
        }
        else {
            mx = pRight->xa + (my - pRight->ya) *
                (double) pRight->dx / (double) pRight->dy;
        }
        /* check miter limit */
        if ((mx * mx + my * my) * 4 > SQSECANT * lw * lw)
            joinStyle = JoinBevel;
    }

    if (joinStyle == JoinMiter) {
        slopes[2].dx = pLeft->dx;
        slopes[2].dy = pLeft->dy;
        slopes[2].k = pLeft->k;
        if (swapslopes) {
            slopes[2].dx = -slopes[2].dx;
            slopes[2].dy = -slopes[2].dy;
            slopes[2].k = -slopes[2].k;
        }
        vertices[3].x = mx;
        vertices[3].y = my;
        slopes[3].dx = pRight->dx;
        slopes[3].dy = pRight->dy;
        slopes[3].k = pRight->k;
        if (swapslopes) {
            slopes[3].dx = -slopes[3].dx;
            slopes[3].dy = -slopes[3].dy;
            slopes[3].k = -slopes[3].k;
        }
        edgecount = 4;
    }
    else {
        double scale, dx, dy, adx, ady;

        adx = dx = pRight->xa - pLeft->xa;
        ady = dy = pRight->ya - pLeft->ya;
        if (adx < 0)
            adx = -adx;
        if (ady < 0)
            ady = -ady;
        scale = ady;
        if (adx > ady)
            scale = adx;
        slopes[2].dx = (dx * 65536) / scale;
        slopes[2].dy = (dy * 65536) / scale;
        slopes[2].k = ((pLeft->xa + pRight->xa) * slopes[2].dy -
                       (pLeft->ya + pRight->ya) * slopes[2].dx) / 2.0;
        edgecount = 3;
    }

    y = miPolyBuildPoly(vertices, slopes, edgecount, pLeft->x, pLeft->y,
                        left, right, &nleft, &nright, &height);
    miFillPolyHelper(pDrawable, pGC, pixel, spanData, y, height, left, right,
                     nleft, nright);
}

static int
miLineArcI(DrawablePtr pDraw,
           GCPtr pGC, int xorg, int yorg, DDXPointPtr points, int *widths)
{
    DDXPointPtr tpts, bpts;
    int *twids, *bwids;
    int x, y, e, ex, slw;

    tpts = points;
    twids = widths;
    if (pGC->miTranslate) {
        xorg += pDraw->x;
        yorg += pDraw->y;
    }
    slw = pGC->lineWidth;
    if (slw == 1) {
        tpts->x = xorg;
        tpts->y = yorg;
        *twids = 1;
        return 1;
    }
    bpts = tpts + slw;
    bwids = twids + slw;
    y = (slw >> 1) + 1;
    if (slw & 1)
        e = -((y << 2) + 3);
    else
        e = -(y << 3);
    ex = -4;
    x = 0;
    while (y) {
        e += (y << 3) - 4;
        while (e >= 0) {
            x++;
            e += (ex = -((x << 3) + 4));
        }
        y--;
        slw = (x << 1) + 1;
        if ((e == ex) && (slw > 1))
            slw--;
        tpts->x = xorg - x;
        tpts->y = yorg - y;
        tpts++;
        *twids++ = slw;
        if ((y != 0) && ((slw > 1) || (e != ex))) {
            bpts--;
            bpts->x = xorg - x;
            bpts->y = yorg + y;
            *--bwids = slw;
        }
    }
    return pGC->lineWidth;
}

#define CLIPSTEPEDGE(edgey,edge,edgeleft) \
    if (ybase == edgey) \
    { \
	if (edgeleft) \
	{ \
	    if (edge->x > xcl) \
		xcl = edge->x; \
	} \
	else \
	{ \
	    if (edge->x < xcr) \
		xcr = edge->x; \
	} \
	edgey++; \
	edge->x += edge->stepx; \
	edge->e += edge->dx; \
	if (edge->e > 0) \
	{ \
	    edge->x += edge->signdx; \
	    edge->e -= edge->dy; \
	} \
    }

static int
miLineArcD(DrawablePtr pDraw,
           GCPtr pGC,
           double xorg,
           double yorg,
           DDXPointPtr points,
           int *widths,
           PolyEdgePtr edge1,
           int edgey1,
           Bool edgeleft1, PolyEdgePtr edge2, int edgey2, Bool edgeleft2)
{
    DDXPointPtr pts;
    int *wids;
    double radius, x0, y0, el, er, yk, xlk, xrk, k;
    int xbase, ybase, y, boty, xl, xr, xcl, xcr;
    int ymin, ymax;
    Bool edge1IsMin, edge2IsMin;
    int ymin1, ymin2;

    pts = points;
    wids = widths;
    xbase = floor(xorg);
    x0 = xorg - xbase;
    ybase = ICEIL(yorg);
    y0 = yorg - ybase;
    if (pGC->miTranslate) {
        xbase += pDraw->x;
        ybase += pDraw->y;
        edge1->x += pDraw->x;
        edge2->x += pDraw->x;
        edgey1 += pDraw->y;
        edgey2 += pDraw->y;
    }
    xlk = x0 + x0 + 1.0;
    xrk = x0 + x0 - 1.0;
    yk = y0 + y0 - 1.0;
    radius = ((double) pGC->lineWidth) / 2.0;
    y = floor(radius - y0 + 1.0);
    ybase -= y;
    ymin = ybase;
    ymax = 65536;
    edge1IsMin = FALSE;
    ymin1 = edgey1;
    if (edge1->dy >= 0) {
        if (!edge1->dy) {
            if (edgeleft1)
                edge1IsMin = TRUE;
            else
                ymax = edgey1;
            edgey1 = 65536;
        }
        else {
            if ((edge1->signdx < 0) == edgeleft1)
                edge1IsMin = TRUE;
        }
    }
    edge2IsMin = FALSE;
    ymin2 = edgey2;
    if (edge2->dy >= 0) {
        if (!edge2->dy) {
            if (edgeleft2)
                edge2IsMin = TRUE;
            else
                ymax = edgey2;
            edgey2 = 65536;
        }
        else {
            if ((edge2->signdx < 0) == edgeleft2)
                edge2IsMin = TRUE;
        }
    }
    if (edge1IsMin) {
        ymin = ymin1;
        if (edge2IsMin && ymin1 > ymin2)
            ymin = ymin2;
    }
    else if (edge2IsMin)
        ymin = ymin2;
    el = radius * radius - ((y + y0) * (y + y0)) - (x0 * x0);
    er = el + xrk;
    xl = 1;
    xr = 0;
    if (x0 < 0.5) {
        xl = 0;
        el -= xlk;
    }
    boty = (y0 < -0.5) ? 1 : 0;
    if (ybase + y - boty > ymax)
        boty = ymax - ybase - y;
    while (y > boty) {
        k = (y << 1) + yk;
        er += k;
        while (er > 0.0) {
            xr++;
            er += xrk - (xr << 1);
        }
        el += k;
        while (el >= 0.0) {
            xl--;
            el += (xl << 1) - xlk;
        }
        y--;
        ybase++;
        if (ybase < ymin)
            continue;
        xcl = xl + xbase;
        xcr = xr + xbase;
        CLIPSTEPEDGE(edgey1, edge1, edgeleft1);
        CLIPSTEPEDGE(edgey2, edge2, edgeleft2);
        if (xcr >= xcl) {
            pts->x = xcl;
            pts->y = ybase;
            pts++;
            *wids++ = xcr - xcl + 1;
        }
    }
    er = xrk - (xr << 1) - er;
    el = (xl << 1) - xlk - el;
    boty = floor(-y0 - radius + 1.0);
    if (ybase + y - boty > ymax)
        boty = ymax - ybase - y;
    while (y > boty) {
        k = (y << 1) + yk;
        er -= k;
        while ((er >= 0.0) && (xr >= 0)) {
            xr--;
            er += xrk - (xr << 1);
        }
        el -= k;
        while ((el > 0.0) && (xl <= 0)) {
            xl++;
            el += (xl << 1) - xlk;
        }
        y--;
        ybase++;
        if (ybase < ymin)
            continue;
        xcl = xl + xbase;
        xcr = xr + xbase;
        CLIPSTEPEDGE(edgey1, edge1, edgeleft1);
        CLIPSTEPEDGE(edgey2, edge2, edgeleft2);
        if (xcr >= xcl) {
            pts->x = xcl;
            pts->y = ybase;
            pts++;
            *wids++ = xcr - xcl + 1;
        }
    }
    return pts - points;
}

static int
miRoundJoinFace(LineFacePtr face, PolyEdgePtr edge, Bool *leftEdge)
{
    int y;
    int dx, dy;
    double xa, ya;
    Bool left;

    dx = -face->dy;
    dy = face->dx;
    xa = face->xa;
    ya = face->ya;
    left = 1;
    if (ya > 0) {
        ya = 0.0;
        xa = 0.0;
    }
    if (dy < 0 || (dy == 0 && dx > 0)) {
        dx = -dx;
        dy = -dy;
        left = !left;
    }
    if (dx == 0 && dy == 0)
        dy = 1;
    if (dy == 0) {
        y = ICEIL(face->ya) + face->y;
        edge->x = -32767;
        edge->stepx = 0;
        edge->signdx = 0;
        edge->e = -1;
        edge->dy = 0;
        edge->dx = 0;
        edge->height = 0;
    }
    else {
        y = miPolyBuildEdge(xa, ya, 0.0, dx, dy, face->x, face->y, !left, edge);
        edge->height = 32767;
    }
    *leftEdge = !left;
    return y;
}

void
miRoundJoinClip(LineFacePtr pLeft, LineFacePtr pRight,
                PolyEdgePtr edge1, PolyEdgePtr edge2,
                int *y1, int *y2, Bool *left1, Bool *left2)
{
    double denom;

    denom = -pLeft->dx * (double) pRight->dy + pRight->dx * (double) pLeft->dy;

    if (denom >= 0) {
        pLeft->xa = -pLeft->xa;
        pLeft->ya = -pLeft->ya;
    }
    else {
        pRight->xa = -pRight->xa;
        pRight->ya = -pRight->ya;
    }
    *y1 = miRoundJoinFace(pLeft, edge1, left1);
    *y2 = miRoundJoinFace(pRight, edge2, left2);
}

int
miRoundCapClip(LineFacePtr face, Bool isInt, PolyEdgePtr edge, Bool *leftEdge)
{
    int y;
    int dx, dy;
    double xa, ya, k;
    Bool left;

    dx = -face->dy;
    dy = face->dx;
    xa = face->xa;
    ya = face->ya;
    k = 0.0;
    if (!isInt)
        k = face->k;
    left = 1;
    if (dy < 0 || (dy == 0 && dx > 0)) {
        dx = -dx;
        dy = -dy;
        xa = -xa;
        ya = -ya;
        left = !left;
    }
    if (dx == 0 && dy == 0)
        dy = 1;
    if (dy == 0) {
        y = ICEIL(face->ya) + face->y;
        edge->x = -32767;
        edge->stepx = 0;
        edge->signdx = 0;
        edge->e = -1;
        edge->dy = 0;
        edge->dx = 0;
        edge->height = 0;
    }
    else {
        y = miPolyBuildEdge(xa, ya, k, dx, dy, face->x, face->y, !left, edge);
        edge->height = 32767;
    }
    *leftEdge = !left;
    return y;
}

static void
miLineArc(DrawablePtr pDraw,
          GCPtr pGC,
          unsigned long pixel,
          SpanDataPtr spanData,
          LineFacePtr leftFace,
          LineFacePtr rightFace, double xorg, double yorg, Bool isInt)
{
    int xorgi = 0, yorgi = 0;
    Spans spanRec;
    int n;
    PolyEdgeRec edge1, edge2;
    int edgey1, edgey2;
    Bool edgeleft1, edgeleft2;

    if (isInt) {
        xorgi = leftFace ? leftFace->x : rightFace->x;
        yorgi = leftFace ? leftFace->y : rightFace->y;
    }
    edgey1 = 65536;
    edgey2 = 65536;
    edge1.x = 0;                /* not used, keep memory checkers happy */
    edge1.dy = -1;
    edge2.x = 0;                /* not used, keep memory checkers happy */
    edge2.dy = -1;
    edgeleft1 = FALSE;
    edgeleft2 = FALSE;
    if ((pGC->lineStyle != LineSolid || pGC->lineWidth > 2) &&
        ((pGC->capStyle == CapRound && pGC->joinStyle != JoinRound) ||
         (pGC->joinStyle == JoinRound && pGC->capStyle == CapButt))) {
        if (isInt) {
            xorg = (double) xorgi;
            yorg = (double) yorgi;
        }
        if (leftFace && rightFace) {
            miRoundJoinClip(leftFace, rightFace, &edge1, &edge2,
                            &edgey1, &edgey2, &edgeleft1, &edgeleft2);
        }
        else if (leftFace) {
            edgey1 = miRoundCapClip(leftFace, isInt, &edge1, &edgeleft1);
        }
        else if (rightFace) {
            edgey2 = miRoundCapClip(rightFace, isInt, &edge2, &edgeleft2);
        }
        isInt = FALSE;
    }
    if (!InitSpans(&spanRec, pGC->lineWidth))
        return;
    if (isInt)
        n = miLineArcI(pDraw, pGC, xorgi, yorgi, spanRec.points,
                       spanRec.widths);
    else
        n = miLineArcD(pDraw, pGC, xorg, yorg, spanRec.points, spanRec.widths,
                       &edge1, edgey1, edgeleft1, &edge2, edgey2, edgeleft2);
    spanRec.count = n;
    fillSpans(pDraw, pGC, pixel, &spanRec, spanData);
}

static void
miLineProjectingCap(DrawablePtr pDrawable, GCPtr pGC, unsigned long pixel,
                    SpanDataPtr spanData, LineFacePtr face, Bool isLeft,
                    double xorg, double yorg, Bool isInt)
{
    int xorgi = 0, yorgi = 0;
    int lw;
    PolyEdgeRec lefts[4], rights[4];
    int lefty, righty, topy, bottomy;
    PolyEdgePtr left, right;
    PolyEdgePtr top, bottom;
    double xa, ya;
    double k;
    double xap, yap;
    int dx, dy;
    double projectXoff, projectYoff;
    double maxy;
    int finaly;

    if (isInt) {
        xorgi = face->x;
        yorgi = face->y;
    }
    lw = pGC->lineWidth;
    dx = face->dx;
    dy = face->dy;
    k = face->k;
    if (dy == 0) {
        lefts[0].height = lw;
        lefts[0].x = xorgi;
        if (isLeft)
            lefts[0].x -= (lw >> 1);
        lefts[0].stepx = 0;
        lefts[0].signdx = 1;
        lefts[0].e = -lw;
        lefts[0].dx = 0;
        lefts[0].dy = lw;
        rights[0].height = lw;
        rights[0].x = xorgi;
        if (!isLeft)
            rights[0].x += ((lw + 1) >> 1);
        rights[0].stepx = 0;
        rights[0].signdx = 1;
        rights[0].e = -lw;
        rights[0].dx = 0;
        rights[0].dy = lw;
        miFillPolyHelper(pDrawable, pGC, pixel, spanData, yorgi - (lw >> 1), lw,
                         lefts, rights, 1, 1);
    }
    else if (dx == 0) {
        if (dy < 0) {
            dy = -dy;
            isLeft = !isLeft;
        }
        topy = yorgi;
        bottomy = yorgi + dy;
        if (isLeft)
            topy -= (lw >> 1);
        else
            bottomy += (lw >> 1);
        lefts[0].height = bottomy - topy;
        lefts[0].x = xorgi - (lw >> 1);
        lefts[0].stepx = 0;
        lefts[0].signdx = 1;
        lefts[0].e = -dy;
        lefts[0].dx = dx;
        lefts[0].dy = dy;

        rights[0].height = bottomy - topy;
        rights[0].x = lefts[0].x + (lw - 1);
        rights[0].stepx = 0;
        rights[0].signdx = 1;
        rights[0].e = -dy;
        rights[0].dx = dx;
        rights[0].dy = dy;
        miFillPolyHelper(pDrawable, pGC, pixel, spanData, topy, bottomy - topy,
                         lefts, rights, 1, 1);
    }
    else {
        xa = face->xa;
        ya = face->ya;
        projectXoff = -ya;
        projectYoff = xa;
        if (dx < 0) {
            right = &rights[1];
            left = &lefts[0];
            top = &rights[0];
            bottom = &lefts[1];
        }
        else {
            right = &rights[0];
            left = &lefts[1];
            top = &lefts[0];
            bottom = &rights[1];
        }
        if (isLeft) {
            righty = miPolyBuildEdge(xa, ya, k, dx, dy, xorgi, yorgi, 0, right);

            xa = -xa;
            ya = -ya;
            k = -k;
            lefty = miPolyBuildEdge(xa - projectXoff, ya - projectYoff,
                                    k, dx, dy, xorgi, yorgi, 1, left);
            if (dx > 0) {
                ya = -ya;
                xa = -xa;
            }
            xap = xa - projectXoff;
            yap = ya - projectYoff;
            topy = miPolyBuildEdge(xap, yap, xap * dx + yap * dy,
                                   -dy, dx, xorgi, yorgi, dx > 0, top);
            bottomy = miPolyBuildEdge(xa, ya,
                                      0.0, -dy, dx, xorgi, yorgi, dx < 0,
                                      bottom);
            maxy = -ya;
        }
        else {
            righty = miPolyBuildEdge(xa - projectXoff, ya - projectYoff,
                                     k, dx, dy, xorgi, yorgi, 0, right);

            xa = -xa;
            ya = -ya;
            k = -k;
            lefty = miPolyBuildEdge(xa, ya, k, dx, dy, xorgi, yorgi, 1, left);
            if (dx > 0) {
                ya = -ya;
                xa = -xa;
            }
            xap = xa - projectXoff;
            yap = ya - projectYoff;
            topy =
                miPolyBuildEdge(xa, ya, 0.0, -dy, dx, xorgi, xorgi, dx > 0,
                                top);
            bottomy =
                miPolyBuildEdge(xap, yap, xap * dx + yap * dy, -dy, dx, xorgi,
                                xorgi, dx < 0, bottom);
            maxy = -ya + projectYoff;
        }
        finaly = ICEIL(maxy) + yorgi;
        if (dx < 0) {
            left->height = bottomy - lefty;
            right->height = finaly - righty;
            top->height = righty - topy;
        }
        else {
            right->height = bottomy - righty;
            left->height = finaly - lefty;
            top->height = lefty - topy;
        }
        bottom->height = finaly - bottomy;
        miFillPolyHelper(pDrawable, pGC, pixel, spanData, topy,
                         bottom->height + bottomy - topy, lefts, rights, 2, 2);
    }
}

static void
miWideSegment(DrawablePtr pDrawable,
              GCPtr pGC,
              unsigned long pixel,
              SpanDataPtr spanData,
              int x1,
              int y1,
              int x2,
              int y2,
              Bool projectLeft,
              Bool projectRight, LineFacePtr leftFace, LineFacePtr rightFace)
{
    double l, L, r;
    double xa, ya;
    double projectXoff = 0.0, projectYoff = 0.0;
    double k;
    double maxy;
    int x, y;
    int dx, dy;
    int finaly;
    PolyEdgePtr left, right;
    PolyEdgePtr top, bottom;
    int lefty, righty, topy, bottomy;
    int signdx;
    PolyEdgeRec lefts[4], rights[4];
    LineFacePtr tface;
    int lw = pGC->lineWidth;

    /* draw top-to-bottom always */
    if (y2 < y1 || (y2 == y1 && x2 < x1)) {
        x = x1;
        x1 = x2;
        x2 = x;

        y = y1;
        y1 = y2;
        y2 = y;

        x = projectLeft;
        projectLeft = projectRight;
        projectRight = x;

        tface = leftFace;
        leftFace = rightFace;
        rightFace = tface;
    }

    dy = y2 - y1;
    signdx = 1;
    dx = x2 - x1;
    if (dx < 0)
        signdx = -1;

    leftFace->x = x1;
    leftFace->y = y1;
    leftFace->dx = dx;
    leftFace->dy = dy;

    rightFace->x = x2;
    rightFace->y = y2;
    rightFace->dx = -dx;
    rightFace->dy = -dy;

    if (dy == 0) {
        rightFace->xa = 0;
        rightFace->ya = (double) lw / 2.0;
        rightFace->k = -(double) (lw * dx) / 2.0;
        leftFace->xa = 0;
        leftFace->ya = -rightFace->ya;
        leftFace->k = rightFace->k;
        x = x1;
        if (projectLeft)
            x -= (lw >> 1);
        y = y1 - (lw >> 1);
        dx = x2 - x;
        if (projectRight)
            dx += ((lw + 1) >> 1);
        dy = lw;
        miFillRectPolyHelper(pDrawable, pGC, pixel, spanData, x, y, dx, dy);
    }
    else if (dx == 0) {
        leftFace->xa = (double) lw / 2.0;
        leftFace->ya = 0;
        leftFace->k = (double) (lw * dy) / 2.0;
        rightFace->xa = -leftFace->xa;
        rightFace->ya = 0;
        rightFace->k = leftFace->k;
        y = y1;
        if (projectLeft)
            y -= lw >> 1;
        x = x1 - (lw >> 1);
        dy = y2 - y;
        if (projectRight)
            dy += ((lw + 1) >> 1);
        dx = lw;
        miFillRectPolyHelper(pDrawable, pGC, pixel, spanData, x, y, dx, dy);
    }
    else {
        l = ((double) lw) / 2.0;
        L = hypot((double) dx, (double) dy);

        if (dx < 0) {
            right = &rights[1];
            left = &lefts[0];
            top = &rights[0];
            bottom = &lefts[1];
        }
        else {
            right = &rights[0];
            left = &lefts[1];
            top = &lefts[0];
            bottom = &rights[1];
        }
        r = l / L;

        /* coord of upper bound at integral y */
        ya = -r * dx;
        xa = r * dy;

        if (projectLeft | projectRight) {
            projectXoff = -ya;
            projectYoff = xa;
        }

        /* xa * dy - ya * dx */
        k = l * L;

        leftFace->xa = xa;
        leftFace->ya = ya;
        leftFace->k = k;
        rightFace->xa = -xa;
        rightFace->ya = -ya;
        rightFace->k = k;

        if (projectLeft)
            righty = miPolyBuildEdge(xa - projectXoff, ya - projectYoff,
                                     k, dx, dy, x1, y1, 0, right);
        else
            righty = miPolyBuildEdge(xa, ya, k, dx, dy, x1, y1, 0, right);

        /* coord of lower bound at integral y */
        ya = -ya;
        xa = -xa;

        /* xa * dy - ya * dx */
        k = -k;

        if (projectLeft)
            lefty = miPolyBuildEdge(xa - projectXoff, ya - projectYoff,
                                    k, dx, dy, x1, y1, 1, left);
        else
            lefty = miPolyBuildEdge(xa, ya, k, dx, dy, x1, y1, 1, left);

        /* coord of top face at integral y */

        if (signdx > 0) {
            ya = -ya;
            xa = -xa;
        }

        if (projectLeft) {
            double xap = xa - projectXoff;
            double yap = ya - projectYoff;

            topy = miPolyBuildEdge(xap, yap, xap * dx + yap * dy,
                                   -dy, dx, x1, y1, dx > 0, top);
        }
        else
            topy = miPolyBuildEdge(xa, ya, 0.0, -dy, dx, x1, y1, dx > 0, top);

        /* coord of bottom face at integral y */

        if (projectRight) {
            double xap = xa + projectXoff;
            double yap = ya + projectYoff;

            bottomy = miPolyBuildEdge(xap, yap, xap * dx + yap * dy,
                                      -dy, dx, x2, y2, dx < 0, bottom);
            maxy = -ya + projectYoff;
        }
        else {
            bottomy = miPolyBuildEdge(xa, ya,
                                      0.0, -dy, dx, x2, y2, dx < 0, bottom);
            maxy = -ya;
        }

        finaly = ICEIL(maxy) + y2;

        if (dx < 0) {
            left->height = bottomy - lefty;
            right->height = finaly - righty;
            top->height = righty - topy;
        }
        else {
            right->height = bottomy - righty;
            left->height = finaly - lefty;
            top->height = lefty - topy;
        }
        bottom->height = finaly - bottomy;
        miFillPolyHelper(pDrawable, pGC, pixel, spanData, topy,
                         bottom->height + bottomy - topy, lefts, rights, 2, 2);
    }
}

static SpanDataPtr
miSetupSpanData(GCPtr pGC, SpanDataPtr spanData, int npt)
{
    if ((npt < 3 && pGC->capStyle != CapRound) || miSpansEasyRop(pGC->alu))
        return (SpanDataPtr) NULL;
    if (pGC->lineStyle == LineDoubleDash)
        miInitSpanGroup(&spanData->bgGroup);
    miInitSpanGroup(&spanData->fgGroup);
    return spanData;
}

static void
miCleanupSpanData(DrawablePtr pDrawable, GCPtr pGC, SpanDataPtr spanData)
{
    if (pGC->lineStyle == LineDoubleDash) {
        ChangeGCVal oldPixel, pixel;

        pixel.val = pGC->bgPixel;
        oldPixel.val = pGC->fgPixel;
        if (pixel.val != oldPixel.val) {
            ChangeGC(NullClient, pGC, GCForeground, &pixel);
            ValidateGC(pDrawable, pGC);
        }
        miFillUniqueSpanGroup(pDrawable, pGC, &spanData->bgGroup);
        miFreeSpanGroup(&spanData->bgGroup);
        if (pixel.val != oldPixel.val) {
            ChangeGC(NullClient, pGC, GCForeground, &oldPixel);
            ValidateGC(pDrawable, pGC);
        }
    }
    miFillUniqueSpanGroup(pDrawable, pGC, &spanData->fgGroup);
    miFreeSpanGroup(&spanData->fgGroup);
}

void
miWideLine(DrawablePtr pDrawable, GCPtr pGC,
           int mode, int npt, DDXPointPtr pPts)
{
    int x1, y1, x2, y2;
    SpanDataRec spanDataRec;
    SpanDataPtr spanData;
    long pixel;
    Bool projectLeft, projectRight;
    LineFaceRec leftFace, rightFace, prevRightFace;
    LineFaceRec firstFace;
    int first;
    Bool somethingDrawn = FALSE;
    Bool selfJoin;

    spanData = miSetupSpanData(pGC, &spanDataRec, npt);
    pixel = pGC->fgPixel;
    x2 = pPts->x;
    y2 = pPts->y;
    first = TRUE;
    selfJoin = FALSE;
    if (npt > 1) {
        if (mode == CoordModePrevious) {
            int nptTmp;
            DDXPointPtr pPtsTmp;

            x1 = x2;
            y1 = y2;
            nptTmp = npt;
            pPtsTmp = pPts + 1;
            while (--nptTmp) {
                x1 += pPtsTmp->x;
                y1 += pPtsTmp->y;
                ++pPtsTmp;
            }
            if (x2 == x1 && y2 == y1)
                selfJoin = TRUE;
        }
        else if (x2 == pPts[npt - 1].x && y2 == pPts[npt - 1].y) {
            selfJoin = TRUE;
        }
    }
    projectLeft = pGC->capStyle == CapProjecting && !selfJoin;
    projectRight = FALSE;
    while (--npt) {
        x1 = x2;
        y1 = y2;
        ++pPts;
        x2 = pPts->x;
        y2 = pPts->y;
        if (mode == CoordModePrevious) {
            x2 += x1;
            y2 += y1;
        }
        if (x1 != x2 || y1 != y2) {
            somethingDrawn = TRUE;
            if (npt == 1 && pGC->capStyle == CapProjecting && !selfJoin)
                projectRight = TRUE;
            miWideSegment(pDrawable, pGC, pixel, spanData, x1, y1, x2, y2,
                          projectLeft, projectRight, &leftFace, &rightFace);
            if (first) {
                if (selfJoin)
                    firstFace = leftFace;
                else if (pGC->capStyle == CapRound) {
                    if (pGC->lineWidth == 1 && !spanData)
                        miLineOnePoint(pDrawable, pGC, pixel, spanData, x1, y1);
                    else
                        miLineArc(pDrawable, pGC, pixel, spanData,
                                  &leftFace, (LineFacePtr) NULL,
                                  (double) 0.0, (double) 0.0, TRUE);
                }
            }
            else {
                miLineJoin(pDrawable, pGC, pixel, spanData, &leftFace,
                           &prevRightFace);
            }
            prevRightFace = rightFace;
            first = FALSE;
            projectLeft = FALSE;
        }
        if (npt == 1 && somethingDrawn) {
            if (selfJoin)
                miLineJoin(pDrawable, pGC, pixel, spanData, &firstFace,
                           &rightFace);
            else if (pGC->capStyle == CapRound) {
                if (pGC->lineWidth == 1 && !spanData)
                    miLineOnePoint(pDrawable, pGC, pixel, spanData, x2, y2);
                else
                    miLineArc(pDrawable, pGC, pixel, spanData,
                              (LineFacePtr) NULL, &rightFace,
                              (double) 0.0, (double) 0.0, TRUE);
            }
        }
    }
    /* handle crock where all points are coincedent */
    if (!somethingDrawn) {
        projectLeft = pGC->capStyle == CapProjecting;
        miWideSegment(pDrawable, pGC, pixel, spanData,
                      x2, y2, x2, y2, projectLeft, projectLeft,
                      &leftFace, &rightFace);
        if (pGC->capStyle == CapRound) {
            miLineArc(pDrawable, pGC, pixel, spanData,
                      &leftFace, (LineFacePtr) NULL,
                      (double) 0.0, (double) 0.0, TRUE);
            rightFace.dx = -1;  /* sleezy hack to make it work */
            miLineArc(pDrawable, pGC, pixel, spanData,
                      (LineFacePtr) NULL, &rightFace,
                      (double) 0.0, (double) 0.0, TRUE);
        }
    }
    if (spanData)
        miCleanupSpanData(pDrawable, pGC, spanData);
}

#define V_TOP	    0
#define V_RIGHT	    1
#define V_BOTTOM    2
#define V_LEFT	    3

static void
miWideDashSegment(DrawablePtr pDrawable,
                  GCPtr pGC,
                  SpanDataPtr spanData,
                  int *pDashOffset,
                  int *pDashIndex,
                  int x1,
                  int y1,
                  int x2,
                  int y2,
                  Bool projectLeft,
                  Bool projectRight,
                  LineFacePtr leftFace, LineFacePtr rightFace)
{
    int dashIndex, dashRemain;
    unsigned char *pDash;
    double L, l;
    double k;
    PolyVertexRec vertices[4];
    PolyVertexRec saveRight, saveBottom;
    PolySlopeRec slopes[4];
    PolyEdgeRec left[4], right[4];
    LineFaceRec lcapFace, rcapFace;
    int nleft, nright;
    int h;
    int y;
    int dy, dx;
    unsigned long pixel;
    double LRemain;
    double r;
    double rdx, rdy;
    double dashDx, dashDy;
    double saveK = 0.0;
    Bool first = TRUE;
    double lcenterx, lcentery, rcenterx = 0.0, rcentery = 0.0;
    unsigned long fgPixel, bgPixel;

    dx = x2 - x1;
    dy = y2 - y1;
    dashIndex = *pDashIndex;
    pDash = pGC->dash;
    dashRemain = pDash[dashIndex] - *pDashOffset;
    fgPixel = pGC->fgPixel;
    bgPixel = pGC->bgPixel;
    if (pGC->fillStyle == FillOpaqueStippled || pGC->fillStyle == FillTiled) {
        bgPixel = fgPixel;
    }

    l = ((double) pGC->lineWidth) / 2.0;
    if (dx == 0) {
        L = dy;
        rdx = 0;
        rdy = l;
        if (dy < 0) {
            L = -dy;
            rdy = -l;
        }
    }
    else if (dy == 0) {
        L = dx;
        rdx = l;
        rdy = 0;
        if (dx < 0) {
            L = -dx;
            rdx = -l;
        }
    }
    else {
        L = hypot((double) dx, (double) dy);
        r = l / L;

        rdx = r * dx;
        rdy = r * dy;
    }
    k = l * L;
    LRemain = L;
    /* All position comments are relative to a line with dx and dy > 0,
     * but the code does not depend on this */
    /* top */
    slopes[V_TOP].dx = dx;
    slopes[V_TOP].dy = dy;
    slopes[V_TOP].k = k;
    /* right */
    slopes[V_RIGHT].dx = -dy;
    slopes[V_RIGHT].dy = dx;
    slopes[V_RIGHT].k = 0;
    /* bottom */
    slopes[V_BOTTOM].dx = -dx;
    slopes[V_BOTTOM].dy = -dy;
    slopes[V_BOTTOM].k = k;
    /* left */
    slopes[V_LEFT].dx = dy;
    slopes[V_LEFT].dy = -dx;
    slopes[V_LEFT].k = 0;

    /* preload the start coordinates */
    vertices[V_RIGHT].x = vertices[V_TOP].x = rdy;
    vertices[V_RIGHT].y = vertices[V_TOP].y = -rdx;

    vertices[V_BOTTOM].x = vertices[V_LEFT].x = -rdy;
    vertices[V_BOTTOM].y = vertices[V_LEFT].y = rdx;

    if (projectLeft) {
        vertices[V_TOP].x -= rdx;
        vertices[V_TOP].y -= rdy;

        vertices[V_LEFT].x -= rdx;
        vertices[V_LEFT].y -= rdy;

        slopes[V_LEFT].k = rdx * dx + rdy * dy;
    }

    lcenterx = x1;
    lcentery = y1;

    if (pGC->capStyle == CapRound) {
        lcapFace.dx = dx;
        lcapFace.dy = dy;
        lcapFace.x = x1;
        lcapFace.y = y1;

        rcapFace.dx = -dx;
        rcapFace.dy = -dy;
        rcapFace.x = x1;
        rcapFace.y = y1;
    }
    while (LRemain > dashRemain) {
        dashDx = (dashRemain * dx) / L;
        dashDy = (dashRemain * dy) / L;

        rcenterx = lcenterx + dashDx;
        rcentery = lcentery + dashDy;

        vertices[V_RIGHT].x += dashDx;
        vertices[V_RIGHT].y += dashDy;

        vertices[V_BOTTOM].x += dashDx;
        vertices[V_BOTTOM].y += dashDy;

        slopes[V_RIGHT].k = vertices[V_RIGHT].x * dx + vertices[V_RIGHT].y * dy;

        if (pGC->lineStyle == LineDoubleDash || !(dashIndex & 1)) {
            if (pGC->lineStyle == LineOnOffDash &&
                pGC->capStyle == CapProjecting) {
                saveRight = vertices[V_RIGHT];
                saveBottom = vertices[V_BOTTOM];
                saveK = slopes[V_RIGHT].k;

                if (!first) {
                    vertices[V_TOP].x -= rdx;
                    vertices[V_TOP].y -= rdy;

                    vertices[V_LEFT].x -= rdx;
                    vertices[V_LEFT].y -= rdy;

                    slopes[V_LEFT].k = vertices[V_LEFT].x *
                        slopes[V_LEFT].dy -
                        vertices[V_LEFT].y * slopes[V_LEFT].dx;
                }

                vertices[V_RIGHT].x += rdx;
                vertices[V_RIGHT].y += rdy;

                vertices[V_BOTTOM].x += rdx;
                vertices[V_BOTTOM].y += rdy;

                slopes[V_RIGHT].k = vertices[V_RIGHT].x *
                    slopes[V_RIGHT].dy -
                    vertices[V_RIGHT].y * slopes[V_RIGHT].dx;
            }
            y = miPolyBuildPoly(vertices, slopes, 4, x1, y1,
                                left, right, &nleft, &nright, &h);
            pixel = (dashIndex & 1) ? bgPixel : fgPixel;
            miFillPolyHelper(pDrawable, pGC, pixel, spanData, y, h, left, right,
                             nleft, nright);

            if (pGC->lineStyle == LineOnOffDash) {
                switch (pGC->capStyle) {
                case CapProjecting:
                    vertices[V_BOTTOM] = saveBottom;
                    vertices[V_RIGHT] = saveRight;
                    slopes[V_RIGHT].k = saveK;
                    break;
                case CapRound:
                    if (!first) {
                        if (dx < 0) {
                            lcapFace.xa = -vertices[V_LEFT].x;
                            lcapFace.ya = -vertices[V_LEFT].y;
                            lcapFace.k = slopes[V_LEFT].k;
                        }
                        else {
                            lcapFace.xa = vertices[V_TOP].x;
                            lcapFace.ya = vertices[V_TOP].y;
                            lcapFace.k = -slopes[V_LEFT].k;
                        }
                        miLineArc(pDrawable, pGC, pixel, spanData,
                                  &lcapFace, (LineFacePtr) NULL,
                                  lcenterx, lcentery, FALSE);
                    }
                    if (dx < 0) {
                        rcapFace.xa = vertices[V_BOTTOM].x;
                        rcapFace.ya = vertices[V_BOTTOM].y;
                        rcapFace.k = slopes[V_RIGHT].k;
                    }
                    else {
                        rcapFace.xa = -vertices[V_RIGHT].x;
                        rcapFace.ya = -vertices[V_RIGHT].y;
                        rcapFace.k = -slopes[V_RIGHT].k;
                    }
                    miLineArc(pDrawable, pGC, pixel, spanData,
                              (LineFacePtr) NULL, &rcapFace,
                              rcenterx, rcentery, FALSE);
                    break;
                }
            }
        }
        LRemain -= dashRemain;
        ++dashIndex;
        if (dashIndex == pGC->numInDashList)
            dashIndex = 0;
        dashRemain = pDash[dashIndex];

        lcenterx = rcenterx;
        lcentery = rcentery;

        vertices[V_TOP] = vertices[V_RIGHT];
        vertices[V_LEFT] = vertices[V_BOTTOM];
        slopes[V_LEFT].k = -slopes[V_RIGHT].k;
        first = FALSE;
    }

    if (pGC->lineStyle == LineDoubleDash || !(dashIndex & 1)) {
        vertices[V_TOP].x -= dx;
        vertices[V_TOP].y -= dy;

        vertices[V_LEFT].x -= dx;
        vertices[V_LEFT].y -= dy;

        vertices[V_RIGHT].x = rdy;
        vertices[V_RIGHT].y = -rdx;

        vertices[V_BOTTOM].x = -rdy;
        vertices[V_BOTTOM].y = rdx;

        if (projectRight) {
            vertices[V_RIGHT].x += rdx;
            vertices[V_RIGHT].y += rdy;

            vertices[V_BOTTOM].x += rdx;
            vertices[V_BOTTOM].y += rdy;
            slopes[V_RIGHT].k = vertices[V_RIGHT].x *
                slopes[V_RIGHT].dy - vertices[V_RIGHT].y * slopes[V_RIGHT].dx;
        }
        else
            slopes[V_RIGHT].k = 0;

        if (!first && pGC->lineStyle == LineOnOffDash &&
            pGC->capStyle == CapProjecting) {
            vertices[V_TOP].x -= rdx;
            vertices[V_TOP].y -= rdy;

            vertices[V_LEFT].x -= rdx;
            vertices[V_LEFT].y -= rdy;
            slopes[V_LEFT].k = vertices[V_LEFT].x *
                slopes[V_LEFT].dy - vertices[V_LEFT].y * slopes[V_LEFT].dx;
        }
        else
            slopes[V_LEFT].k += dx * dx + dy * dy;

        y = miPolyBuildPoly(vertices, slopes, 4, x2, y2,
                            left, right, &nleft, &nright, &h);

        pixel = (dashIndex & 1) ? pGC->bgPixel : pGC->fgPixel;
        miFillPolyHelper(pDrawable, pGC, pixel, spanData, y, h, left, right,
                         nleft, nright);
        if (!first && pGC->lineStyle == LineOnOffDash &&
            pGC->capStyle == CapRound) {
            lcapFace.x = x2;
            lcapFace.y = y2;
            if (dx < 0) {
                lcapFace.xa = -vertices[V_LEFT].x;
                lcapFace.ya = -vertices[V_LEFT].y;
                lcapFace.k = slopes[V_LEFT].k;
            }
            else {
                lcapFace.xa = vertices[V_TOP].x;
                lcapFace.ya = vertices[V_TOP].y;
                lcapFace.k = -slopes[V_LEFT].k;
            }
            miLineArc(pDrawable, pGC, pixel, spanData,
                      &lcapFace, (LineFacePtr) NULL, rcenterx, rcentery, FALSE);
        }
    }
    dashRemain = ((double) dashRemain) - LRemain;
    if (dashRemain == 0) {
        dashIndex++;
        if (dashIndex == pGC->numInDashList)
            dashIndex = 0;
        dashRemain = pDash[dashIndex];
    }

    leftFace->x = x1;
    leftFace->y = y1;
    leftFace->dx = dx;
    leftFace->dy = dy;
    leftFace->xa = rdy;
    leftFace->ya = -rdx;
    leftFace->k = k;

    rightFace->x = x2;
    rightFace->y = y2;
    rightFace->dx = -dx;
    rightFace->dy = -dy;
    rightFace->xa = -rdy;
    rightFace->ya = rdx;
    rightFace->k = k;

    *pDashIndex = dashIndex;
    *pDashOffset = pDash[dashIndex] - dashRemain;
}

void
miWideDash(DrawablePtr pDrawable, GCPtr pGC,
           int mode, int npt, DDXPointPtr pPts)
{
    int x1, y1, x2, y2;
    unsigned long pixel;
    Bool projectLeft, projectRight;
    LineFaceRec leftFace, rightFace, prevRightFace;
    LineFaceRec firstFace;
    int first;
    int dashIndex, dashOffset;
    int prevDashIndex;
    SpanDataRec spanDataRec;
    SpanDataPtr spanData;
    Bool somethingDrawn = FALSE;
    Bool selfJoin;
    Bool endIsFg = FALSE, startIsFg = FALSE;
    Bool firstIsFg = FALSE, prevIsFg = FALSE;

#if 0
    /* XXX backward compatibility */
    if (pGC->lineWidth == 0) {
        miZeroDashLine(pDrawable, pGC, mode, npt, pPts);
        return;
    }
#endif
    if (pGC->lineStyle == LineDoubleDash &&
        (pGC->fillStyle == FillOpaqueStippled || pGC->fillStyle == FillTiled)) {
        miWideLine(pDrawable, pGC, mode, npt, pPts);
        return;
    }
    if (npt == 0)
        return;
    spanData = miSetupSpanData(pGC, &spanDataRec, npt);
    x2 = pPts->x;
    y2 = pPts->y;
    first = TRUE;
    selfJoin = FALSE;
    if (mode == CoordModePrevious) {
        int nptTmp;
        DDXPointPtr pPtsTmp;

        x1 = x2;
        y1 = y2;
        nptTmp = npt;
        pPtsTmp = pPts + 1;
        while (--nptTmp) {
            x1 += pPtsTmp->x;
            y1 += pPtsTmp->y;
            ++pPtsTmp;
        }
        if (x2 == x1 && y2 == y1)
            selfJoin = TRUE;
    }
    else if (x2 == pPts[npt - 1].x && y2 == pPts[npt - 1].y) {
        selfJoin = TRUE;
    }
    projectLeft = pGC->capStyle == CapProjecting && !selfJoin;
    projectRight = FALSE;
    dashIndex = 0;
    dashOffset = 0;
    miStepDash((int) pGC->dashOffset, &dashIndex,
               pGC->dash, (int) pGC->numInDashList, &dashOffset);
    while (--npt) {
        x1 = x2;
        y1 = y2;
        ++pPts;
        x2 = pPts->x;
        y2 = pPts->y;
        if (mode == CoordModePrevious) {
            x2 += x1;
            y2 += y1;
        }
        if (x1 != x2 || y1 != y2) {
            somethingDrawn = TRUE;
            if (npt == 1 && pGC->capStyle == CapProjecting &&
                (!selfJoin || !firstIsFg))
                projectRight = TRUE;
            prevDashIndex = dashIndex;
            miWideDashSegment(pDrawable, pGC, spanData, &dashOffset, &dashIndex,
                              x1, y1, x2, y2,
                              projectLeft, projectRight, &leftFace, &rightFace);
            startIsFg = !(prevDashIndex & 1);
            endIsFg = (dashIndex & 1) ^ (dashOffset != 0);
            if (pGC->lineStyle == LineDoubleDash || startIsFg) {
                pixel = startIsFg ? pGC->fgPixel : pGC->bgPixel;
                if (first || (pGC->lineStyle == LineOnOffDash && !prevIsFg)) {
                    if (first && selfJoin) {
                        firstFace = leftFace;
                        firstIsFg = startIsFg;
                    }
                    else if (pGC->capStyle == CapRound)
                        miLineArc(pDrawable, pGC, pixel, spanData,
                                  &leftFace, (LineFacePtr) NULL,
                                  (double) 0.0, (double) 0.0, TRUE);
                }
                else {
                    miLineJoin(pDrawable, pGC, pixel, spanData, &leftFace,
                               &prevRightFace);
                }
            }
            prevRightFace = rightFace;
            prevIsFg = endIsFg;
            first = FALSE;
            projectLeft = FALSE;
        }
        if (npt == 1 && somethingDrawn) {
            if (pGC->lineStyle == LineDoubleDash || endIsFg) {
                pixel = endIsFg ? pGC->fgPixel : pGC->bgPixel;
                if (selfJoin && (pGC->lineStyle == LineDoubleDash || firstIsFg)) {
                    miLineJoin(pDrawable, pGC, pixel, spanData, &firstFace,
                               &rightFace);
                }
                else {
                    if (pGC->capStyle == CapRound)
                        miLineArc(pDrawable, pGC, pixel, spanData,
                                  (LineFacePtr) NULL, &rightFace,
                                  (double) 0.0, (double) 0.0, TRUE);
                }
            }
            else {
                /* glue a cap to the start of the line if
                 * we're OnOffDash and ended on odd dash
                 */
                if (selfJoin && firstIsFg) {
                    pixel = pGC->fgPixel;
                    if (pGC->capStyle == CapProjecting)
                        miLineProjectingCap(pDrawable, pGC, pixel, spanData,
                                            &firstFace, TRUE,
                                            (double) 0.0, (double) 0.0, TRUE);
                    else if (pGC->capStyle == CapRound)
                        miLineArc(pDrawable, pGC, pixel, spanData,
                                  &firstFace, (LineFacePtr) NULL,
                                  (double) 0.0, (double) 0.0, TRUE);
                }
            }
        }
    }
    /* handle crock where all points are coincident */
    if (!somethingDrawn &&
        (pGC->lineStyle == LineDoubleDash || !(dashIndex & 1))) {
        /* not the same as endIsFg computation above */
        pixel = (dashIndex & 1) ? pGC->bgPixel : pGC->fgPixel;
        switch (pGC->capStyle) {
        case CapRound:
            miLineArc(pDrawable, pGC, pixel, spanData,
                      (LineFacePtr) NULL, (LineFacePtr) NULL,
                      (double) x2, (double) y2, FALSE);
            break;
        case CapProjecting:
            x1 = pGC->lineWidth;
            miFillRectPolyHelper(pDrawable, pGC, pixel, spanData,
                                 x2 - (x1 >> 1), y2 - (x1 >> 1), x1, x1);
            break;
        }
    }
    if (spanData)
        miCleanupSpanData(pDrawable, pGC, spanData);
}