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https://gitlab.freedesktop.org/cairo/cairo.git
synced 2026-04-29 11:40:47 +02:00
Fix polygon stroking so last final face is rendered exactly. Fix bug in which XrPolygonAddPt with horizontal edge would then drop the next edge.
This commit is contained in:
Carl Worth
parent
bc362fc2e4
commit
44ca388c90
8 changed files with 66 additions and 54 deletions
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@ -452,7 +452,7 @@ XrError
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XrPenAddPointsForSlopes(XrPen *pen, XPointFixed *a, XPointFixed *b, XPointFixed *c, XPointFixed *d);
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XrError
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XrPenStrokePoints(XrPen *pen, XPointFixed *pt, int num_pts, XrPolygon *polygon);
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XrPenStrokeSpline(XrPen *pen, XrSpline *spline, double tolerance, XrPolygon *polygon);
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/* xrpolygon.c */
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void
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49
src/xrpen.c
49
src/xrpen.c
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@ -41,7 +41,7 @@ static int
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_SlopeCounterClockwise(XrSlopeFixed *a, XrSlopeFixed *b);
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static XrError
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_XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrPolygon *polygon);
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_XrPenStrokeSplineHalf(XrPen *pen, XrSpline *spline, XrPenVertexTag dir, XrPolygon *polygon);
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static int
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_XrPenVertexCompareByTheta(const void *a, const void *b);
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@ -261,14 +261,16 @@ _SlopeCounterClockwise(XrSlopeFixed *a, XrSlopeFixed *b)
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}
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static XrError
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_XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrPolygon *polygon)
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_XrPenStrokeSplineHalf(XrPen *pen, XrSpline *spline, XrPenVertexTag dir, XrPolygon *polygon)
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{
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int i;
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XrError err;
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int start, stop, step;
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int active = 0;
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XPointFixed hull_pt;
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XrSlopeFixed exit_slope;
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XrSlopeFixed slope, final_slope;
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XPointFixed *pt = spline->pts;
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int num_pts = spline->num_pts;
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for (i=0; i < pen->num_vertices; i++) {
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if (pen->vertex[i].tag == dir) {
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@ -279,12 +281,14 @@ _XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrP
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if (dir == XrPenVertexTagForward) {
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start = 0;
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stop = num_pts - 1;
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stop = num_pts;
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step = 1;
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_FindSlope(&spline->c, &spline->d, &final_slope);
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} else {
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start = num_pts - 1;
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stop = 0;
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stop = -1;
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step = -1;
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_FindSlope(&spline->b, &spline->a, &final_slope);
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}
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i = start;
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@ -295,37 +299,42 @@ _XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrP
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if (err)
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return err;
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_FindSlope(&pt[i], &pt[i+step], &exit_slope);
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if (_SlopeCounterClockwise(&exit_slope, &pen->vertex[active].slope_ccw)) {
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active = active + 1;
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if (active == pen->num_vertices)
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if (i + step == stop)
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slope = final_slope;
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else
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_FindSlope(&pt[i], &pt[i+step], &slope);
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if (_SlopeCounterClockwise(&slope, &pen->vertex[active].slope_ccw)) {
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if (++active == pen->num_vertices)
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active = 0;
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} else if (_SlopeClockwise(&exit_slope, &pen->vertex[active].slope_cw)) {
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active = active - 1;
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if (active == -1)
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} else if (_SlopeClockwise(&slope, &pen->vertex[active].slope_cw)) {
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if (--active == -1)
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active = pen->num_vertices - 1;
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} else {
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i += step;
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}
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}
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hull_pt.x = pt[i].x + pen->vertex[active].pt.x;
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hull_pt.y = pt[i].y + pen->vertex[active].pt.y;
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return XrPolygonAddPoint(polygon, &hull_pt);
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return XrErrorSuccess;
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}
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/* Compute convex hull formed by placing a copy of the pen at each of
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the given points. The hull is stored in the provided polygon. */
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/* Compute outline of a given spline by decomposing the spline into
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line segments, then (conceptually) placing the pen at each point
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and computing the convex hull formed by the vertices of all copied
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pens. The hull is stored in the provided polygon. */
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XrError
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XrPenStrokePoints(XrPen *pen, XPointFixed *pt, int num_pts, XrPolygon *polygon)
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XrPenStrokeSpline(XrPen *pen, XrSpline *spline, double tolerance, XrPolygon *polygon)
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{
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XrError err;
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err = _XrPenFindHull(pen, pt, num_pts, XrPenVertexTagForward, polygon);
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err = XrSplineDecompose(spline, tolerance);
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if (err)
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return err;
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err = _XrPenFindHull(pen, pt, num_pts, XrPenVertexTagReverse, polygon);
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err = _XrPenStrokeSplineHalf(pen, spline, XrPenVertexTagForward, polygon);
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if (err)
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return err;
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err = _XrPenStrokeSplineHalf(pen, spline, XrPenVertexTagReverse, polygon);
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if (err)
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return err;
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@ -110,7 +110,7 @@ XrPolygonAddEdge(XrPolygon *polygon, XPointFixed *p1, XPointFixed *p2)
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/* drop horizontal edges */
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if (p1->y == p2->y) {
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return XrErrorSuccess;
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goto DONE;
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}
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if (polygon->num_edges >= polygon->edges_size) {
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@ -133,6 +133,7 @@ XrPolygonAddEdge(XrPolygon *polygon, XPointFixed *p1, XPointFixed *p2)
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polygon->num_edges++;
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DONE:
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_XrPolygonSetLastPoint(polygon, p2);
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return XrErrorSuccess;
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@ -500,9 +500,6 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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XrPenTaggedPoint extra_points[4];
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XrSplineInit(&spline, a, b, c, d);
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err = XrSplineDecompose(&spline, gstate->tolerance);
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if (err)
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goto CLEANUP_SPLINE;
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XrPolygonInit(&polygon);
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@ -544,7 +541,7 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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if (err)
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goto CLEANUP_PEN;
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err = XrPenStrokePoints(&pen, spline.pts, spline.num_pts, &polygon);
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err = XrPenStrokeSpline(&pen, &spline, gstate->tolerance, &polygon);
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if (err)
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goto CLEANUP_PEN;
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@ -554,7 +551,6 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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XrPenDeinit(&pen);
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CLEANUP_POLYGON:
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XrPolygonDeinit(&polygon);
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CLEANUP_SPLINE:
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XrSplineDeinit(&spline);
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return err;
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2
xrint.h
2
xrint.h
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@ -452,7 +452,7 @@ XrError
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XrPenAddPointsForSlopes(XrPen *pen, XPointFixed *a, XPointFixed *b, XPointFixed *c, XPointFixed *d);
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XrError
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XrPenStrokePoints(XrPen *pen, XPointFixed *pt, int num_pts, XrPolygon *polygon);
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XrPenStrokeSpline(XrPen *pen, XrSpline *spline, double tolerance, XrPolygon *polygon);
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/* xrpolygon.c */
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void
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49
xrpen.c
49
xrpen.c
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@ -41,7 +41,7 @@ static int
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_SlopeCounterClockwise(XrSlopeFixed *a, XrSlopeFixed *b);
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static XrError
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_XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrPolygon *polygon);
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_XrPenStrokeSplineHalf(XrPen *pen, XrSpline *spline, XrPenVertexTag dir, XrPolygon *polygon);
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static int
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_XrPenVertexCompareByTheta(const void *a, const void *b);
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@ -261,14 +261,16 @@ _SlopeCounterClockwise(XrSlopeFixed *a, XrSlopeFixed *b)
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}
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static XrError
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_XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrPolygon *polygon)
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_XrPenStrokeSplineHalf(XrPen *pen, XrSpline *spline, XrPenVertexTag dir, XrPolygon *polygon)
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{
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int i;
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XrError err;
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int start, stop, step;
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int active = 0;
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XPointFixed hull_pt;
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XrSlopeFixed exit_slope;
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XrSlopeFixed slope, final_slope;
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XPointFixed *pt = spline->pts;
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int num_pts = spline->num_pts;
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for (i=0; i < pen->num_vertices; i++) {
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if (pen->vertex[i].tag == dir) {
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@ -279,12 +281,14 @@ _XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrP
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if (dir == XrPenVertexTagForward) {
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start = 0;
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stop = num_pts - 1;
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stop = num_pts;
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step = 1;
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_FindSlope(&spline->c, &spline->d, &final_slope);
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} else {
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start = num_pts - 1;
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stop = 0;
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stop = -1;
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step = -1;
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_FindSlope(&spline->b, &spline->a, &final_slope);
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}
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i = start;
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@ -295,37 +299,42 @@ _XrPenFindHull(XrPen *pen, XPointFixed *pt, int num_pts, XrPenVertexTag dir, XrP
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if (err)
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return err;
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_FindSlope(&pt[i], &pt[i+step], &exit_slope);
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if (_SlopeCounterClockwise(&exit_slope, &pen->vertex[active].slope_ccw)) {
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active = active + 1;
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if (active == pen->num_vertices)
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if (i + step == stop)
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slope = final_slope;
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else
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_FindSlope(&pt[i], &pt[i+step], &slope);
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if (_SlopeCounterClockwise(&slope, &pen->vertex[active].slope_ccw)) {
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if (++active == pen->num_vertices)
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active = 0;
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} else if (_SlopeClockwise(&exit_slope, &pen->vertex[active].slope_cw)) {
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active = active - 1;
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if (active == -1)
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} else if (_SlopeClockwise(&slope, &pen->vertex[active].slope_cw)) {
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if (--active == -1)
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active = pen->num_vertices - 1;
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} else {
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i += step;
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}
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}
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hull_pt.x = pt[i].x + pen->vertex[active].pt.x;
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hull_pt.y = pt[i].y + pen->vertex[active].pt.y;
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return XrPolygonAddPoint(polygon, &hull_pt);
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return XrErrorSuccess;
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}
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/* Compute convex hull formed by placing a copy of the pen at each of
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the given points. The hull is stored in the provided polygon. */
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/* Compute outline of a given spline by decomposing the spline into
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line segments, then (conceptually) placing the pen at each point
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and computing the convex hull formed by the vertices of all copied
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pens. The hull is stored in the provided polygon. */
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XrError
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XrPenStrokePoints(XrPen *pen, XPointFixed *pt, int num_pts, XrPolygon *polygon)
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XrPenStrokeSpline(XrPen *pen, XrSpline *spline, double tolerance, XrPolygon *polygon)
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{
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XrError err;
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err = _XrPenFindHull(pen, pt, num_pts, XrPenVertexTagForward, polygon);
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err = XrSplineDecompose(spline, tolerance);
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if (err)
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return err;
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err = _XrPenFindHull(pen, pt, num_pts, XrPenVertexTagReverse, polygon);
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err = _XrPenStrokeSplineHalf(pen, spline, XrPenVertexTagForward, polygon);
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if (err)
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return err;
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err = _XrPenStrokeSplineHalf(pen, spline, XrPenVertexTagReverse, polygon);
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if (err)
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return err;
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@ -110,7 +110,7 @@ XrPolygonAddEdge(XrPolygon *polygon, XPointFixed *p1, XPointFixed *p2)
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/* drop horizontal edges */
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if (p1->y == p2->y) {
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return XrErrorSuccess;
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goto DONE;
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}
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if (polygon->num_edges >= polygon->edges_size) {
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@ -133,6 +133,7 @@ XrPolygonAddEdge(XrPolygon *polygon, XPointFixed *p1, XPointFixed *p2)
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polygon->num_edges++;
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DONE:
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_XrPolygonSetLastPoint(polygon, p2);
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return XrErrorSuccess;
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@ -500,9 +500,6 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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XrPenTaggedPoint extra_points[4];
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XrSplineInit(&spline, a, b, c, d);
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err = XrSplineDecompose(&spline, gstate->tolerance);
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if (err)
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goto CLEANUP_SPLINE;
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XrPolygonInit(&polygon);
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@ -544,7 +541,7 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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if (err)
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goto CLEANUP_PEN;
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err = XrPenStrokePoints(&pen, spline.pts, spline.num_pts, &polygon);
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err = XrPenStrokeSpline(&pen, &spline, gstate->tolerance, &polygon);
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if (err)
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goto CLEANUP_PEN;
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@ -554,7 +551,6 @@ XrStrokerAddSpline (void *closure, XPointFixed *a, XPointFixed *b, XPointFixed *
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XrPenDeinit(&pen);
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CLEANUP_POLYGON:
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XrPolygonDeinit(&polygon);
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CLEANUP_SPLINE:
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XrSplineDeinit(&spline);
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return err;
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