1 /*
2 * Copyright (c) 2007, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation. Oracle designates this
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10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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24 */
25
26 package sun.java2d.marlin;
27
28 import java.util.Arrays;
29 import sun.java2d.marlin.DHelpers.PolyStack;
30
31 // TODO: some of the arithmetic here is too verbose and prone to hard to
32 // debug typos. We should consider making a small Point/Vector class that
33 // has methods like plus(Point), minus(Point), dot(Point), cross(Point)and such
34 final class DStroker implements DPathConsumer2D, MarlinConst {
35
36 private static final int MOVE_TO = 0;
37 private static final int DRAWING_OP_TO = 1; // ie. curve, line, or quad
38 private static final int CLOSE = 2;
39
40 // pisces used to use fixed point arithmetic with 16 decimal digits. I
41 // didn't want to change the values of the constant below when I converted
42 // it to floating point, so that's why the divisions by 2^16 are there.
43 private static final double ROUND_JOIN_THRESHOLD = 1000.0d/65536.0d;
44
45 // kappa = (4/3) * (SQRT(2) - 1)
46 private static final double C = (4.0d * (Math.sqrt(2.0d) - 1.0d) / 3.0d);
47
48 // SQRT(2)
49 private static final double SQRT_2 = Math.sqrt(2.0d);
50
51 private static final int MAX_N_CURVES = 11;
52
53 private DPathConsumer2D out;
54
55 private int capStyle;
56 private int joinStyle;
57
58 private double lineWidth2;
59 private double invHalfLineWidth2Sq;
60
61 private final double[] offset0 = new double[2];
62 private final double[] offset1 = new double[2];
63 private final double[] offset2 = new double[2];
64 private final double[] miter = new double[2];
65 private double miterLimitSq;
66
67 private int prev;
68
69 // The starting point of the path, and the slope there.
70 private double sx0, sy0, sdx, sdy;
71 // the current point and the slope there.
72 private double cx0, cy0, cdx, cdy; // c stands for current
73 // vectors that when added to (sx0,sy0) and (cx0,cy0) respectively yield the
74 // first and last points on the left parallel path. Since this path is
75 // parallel, it's slope at any point is parallel to the slope of the
76 // original path (thought they may have different directions), so these
77 // could be computed from sdx,sdy and cdx,cdy (and vice versa), but that
78 // would be error prone and hard to read, so we keep these anyway.
79 private double smx, smy, cmx, cmy;
80
81 private final PolyStack reverse;
82
83 // This is where the curve to be processed is put. We give it
84 // enough room to store all curves.
85 private final double[] middle = new double[MAX_N_CURVES * 6 + 2];
86 private final double[] lp = new double[8];
87 private final double[] rp = new double[8];
88 private final double[] subdivTs = new double[MAX_N_CURVES - 1];
89
90 // per-thread renderer context
91 final DRendererContext rdrCtx;
92
93 // dirty curve
94 final DCurve curve;
95
96 // Bounds of the drawing region, at pixel precision.
97 private double[] clipRect;
98
99 // the outcode of the current point
100 private int cOutCode = 0;
101
102 // the outcode of the starting point
103 private int sOutCode = 0;
104
105 // flag indicating if the path is opened (clipped)
106 private boolean opened = false;
107 // flag indicating if the starting point's cap is done
108 private boolean capStart = false;
109
110 /**
111 * Constructs a <code>DStroker</code>.
112 * @param rdrCtx per-thread renderer context
113 */
114 DStroker(final DRendererContext rdrCtx) {
115 this.rdrCtx = rdrCtx;
116
117 this.reverse = (rdrCtx.stats != null) ?
118 new PolyStack(rdrCtx,
119 rdrCtx.stats.stat_str_polystack_types,
120 rdrCtx.stats.stat_str_polystack_curves,
121 rdrCtx.stats.hist_str_polystack_curves,
122 rdrCtx.stats.stat_array_str_polystack_curves,
123 rdrCtx.stats.stat_array_str_polystack_types)
124 : new PolyStack(rdrCtx);
125
126 this.curve = rdrCtx.curve;
127 }
128
129 /**
130 * Inits the <code>DStroker</code>.
131 *
132 * @param pc2d an output <code>DPathConsumer2D</code>.
133 * @param lineWidth the desired line width in pixels
134 * @param capStyle the desired end cap style, one of
135 * <code>CAP_BUTT</code>, <code>CAP_ROUND</code> or
136 * <code>CAP_SQUARE</code>.
137 * @param joinStyle the desired line join style, one of
138 * <code>JOIN_MITER</code>, <code>JOIN_ROUND</code> or
139 * <code>JOIN_BEVEL</code>.
140 * @param miterLimit the desired miter limit
141 * @param scale scaling factor applied to clip boundaries
142 * @return this instance
143 */
144 DStroker init(final DPathConsumer2D pc2d,
145 final double lineWidth,
146 final int capStyle,
147 final int joinStyle,
148 final double miterLimit,
149 final double scale)
150 {
151 this.out = pc2d;
152
153 this.lineWidth2 = lineWidth / 2.0d;
154 this.invHalfLineWidth2Sq = 1.0d / (2.0d * lineWidth2 * lineWidth2);
155 this.capStyle = capStyle;
156 this.joinStyle = joinStyle;
157
158 final double limit = miterLimit * lineWidth2;
159 this.miterLimitSq = limit * limit;
160
161 this.prev = CLOSE;
162
163 rdrCtx.stroking = 1;
164
165 if (rdrCtx.doClip) {
166 // Adjust the clipping rectangle with the stroker margin (miter limit, width)
167 double rdrOffX = 0.0d, rdrOffY = 0.0d;
168 double margin = lineWidth2;
169
170 if (capStyle == CAP_SQUARE) {
171 margin *= SQRT_2;
172 }
173 if ((joinStyle == JOIN_MITER) && (margin < limit)) {
174 margin = limit;
175 }
176 if (scale != 1.0d) {
177 margin *= scale;
178 rdrOffX = scale * DRenderer.RDR_OFFSET_X;
179 rdrOffY = scale * DRenderer.RDR_OFFSET_Y;
180 }
181 // add a small rounding error:
182 margin += 1e-3d;
183
184 // bounds as half-open intervals: minX <= x < maxX and minY <= y < maxY
185 // adjust clip rectangle (ymin, ymax, xmin, xmax):
186 final double[] _clipRect = rdrCtx.clipRect;
187 _clipRect[0] -= margin - rdrOffY;
188 _clipRect[1] += margin + rdrOffY;
189 _clipRect[2] -= margin - rdrOffX;
190 _clipRect[3] += margin + rdrOffX;
191 this.clipRect = _clipRect;
192 } else {
193 this.clipRect = null;
194 this.cOutCode = 0;
195 this.sOutCode = 0;
196 }
197 return this; // fluent API
198 }
199
200 /**
201 * Disposes this stroker:
202 * clean up before reusing this instance
203 */
204 void dispose() {
205 reverse.dispose();
206
207 opened = false;
208 capStart = false;
209
210 if (DO_CLEAN_DIRTY) {
211 // Force zero-fill dirty arrays:
212 Arrays.fill(offset0, 0.0d);
213 Arrays.fill(offset1, 0.0d);
214 Arrays.fill(offset2, 0.0d);
215 Arrays.fill(miter, 0.0d);
216 Arrays.fill(middle, 0.0d);
217 Arrays.fill(lp, 0.0d);
218 Arrays.fill(rp, 0.0d);
219 Arrays.fill(subdivTs, 0.0d);
220 }
221 }
222
223 private static void computeOffset(final double lx, final double ly,
224 final double w, final double[] m)
225 {
226 double len = lx*lx + ly*ly;
227 if (len == 0.0d) {
228 m[0] = 0.0d;
229 m[1] = 0.0d;
230 } else {
231 len = Math.sqrt(len);
232 m[0] = (ly * w) / len;
233 m[1] = -(lx * w) / len;
234 }
235 }
236
237 // Returns true if the vectors (dx1, dy1) and (dx2, dy2) are
238 // clockwise (if dx1,dy1 needs to be rotated clockwise to close
239 // the smallest angle between it and dx2,dy2).
240 // This is equivalent to detecting whether a point q is on the right side
241 // of a line passing through points p1, p2 where p2 = p1+(dx1,dy1) and
242 // q = p2+(dx2,dy2), which is the same as saying p1, p2, q are in a
243 // clockwise order.
244 // NOTE: "clockwise" here assumes coordinates with 0,0 at the bottom left.
245 private static boolean isCW(final double dx1, final double dy1,
246 final double dx2, final double dy2)
247 {
248 return dx1 * dy2 <= dy1 * dx2;
249 }
250
251 private void drawRoundJoin(double x, double y,
252 double omx, double omy, double mx, double my,
253 boolean rev,
254 double threshold)
255 {
256 if ((omx == 0.0d && omy == 0.0d) || (mx == 0.0d && my == 0.0d)) {
257 return;
258 }
259
260 double domx = omx - mx;
261 double domy = omy - my;
262 double len = domx*domx + domy*domy;
263 if (len < threshold) {
264 return;
265 }
266
267 if (rev) {
268 omx = -omx;
269 omy = -omy;
270 mx = -mx;
271 my = -my;
272 }
273 drawRoundJoin(x, y, omx, omy, mx, my, rev);
274 }
275
276 private void drawRoundJoin(double cx, double cy,
277 double omx, double omy,
278 double mx, double my,
279 boolean rev)
280 {
281 // The sign of the dot product of mx,my and omx,omy is equal to the
282 // the sign of the cosine of ext
283 // (ext is the angle between omx,omy and mx,my).
284 final double cosext = omx * mx + omy * my;
285 // If it is >=0, we know that abs(ext) is <= 90 degrees, so we only
286 // need 1 curve to approximate the circle section that joins omx,omy
287 // and mx,my.
288 final int numCurves = (cosext >= 0.0d) ? 1 : 2;
289
290 switch (numCurves) {
291 case 1:
292 drawBezApproxForArc(cx, cy, omx, omy, mx, my, rev);
293 break;
364 emitCurveTo(x1, y1, x2, y2, x3, y3, x4, y4, rev);
365 }
366
367 private void drawRoundCap(double cx, double cy, double mx, double my) {
368 final double Cmx = C * mx;
369 final double Cmy = C * my;
370 emitCurveTo(cx + mx - Cmy, cy + my + Cmx,
371 cx - my + Cmx, cy + mx + Cmy,
372 cx - my, cy + mx);
373 emitCurveTo(cx - my - Cmx, cy + mx - Cmy,
374 cx - mx - Cmy, cy - my + Cmx,
375 cx - mx, cy - my);
376 }
377
378 // Return the intersection point of the lines (x0, y0) -> (x1, y1)
379 // and (x0p, y0p) -> (x1p, y1p) in m[off] and m[off+1]
380 private static void computeMiter(final double x0, final double y0,
381 final double x1, final double y1,
382 final double x0p, final double y0p,
383 final double x1p, final double y1p,
384 final double[] m, int off)
385 {
386 double x10 = x1 - x0;
387 double y10 = y1 - y0;
388 double x10p = x1p - x0p;
389 double y10p = y1p - y0p;
390
391 // if this is 0, the lines are parallel. If they go in the
392 // same direction, there is no intersection so m[off] and
393 // m[off+1] will contain infinity, so no miter will be drawn.
394 // If they go in the same direction that means that the start of the
395 // current segment and the end of the previous segment have the same
396 // tangent, in which case this method won't even be involved in
397 // miter drawing because it won't be called by drawMiter (because
398 // (mx == omx && my == omy) will be true, and drawMiter will return
399 // immediately).
400 double den = x10*y10p - x10p*y10;
401 double t = x10p*(y0-y0p) - y10p*(x0-x0p);
402 t /= den;
403 m[off++] = x0 + t*x10;
404 m[off] = y0 + t*y10;
405 }
406
407 // Return the intersection point of the lines (x0, y0) -> (x1, y1)
408 // and (x0p, y0p) -> (x1p, y1p) in m[off] and m[off+1]
409 private static void safeComputeMiter(final double x0, final double y0,
410 final double x1, final double y1,
411 final double x0p, final double y0p,
412 final double x1p, final double y1p,
413 final double[] m, int off)
414 {
415 double x10 = x1 - x0;
416 double y10 = y1 - y0;
417 double x10p = x1p - x0p;
418 double y10p = y1p - y0p;
419
420 // if this is 0, the lines are parallel. If they go in the
421 // same direction, there is no intersection so m[off] and
422 // m[off+1] will contain infinity, so no miter will be drawn.
423 // If they go in the same direction that means that the start of the
424 // current segment and the end of the previous segment have the same
425 // tangent, in which case this method won't even be involved in
426 // miter drawing because it won't be called by drawMiter (because
427 // (mx == omx && my == omy) will be true, and drawMiter will return
428 // immediately).
429 double den = x10*y10p - x10p*y10;
430 if (den == 0.0d) {
431 m[off++] = (x0 + x0p) / 2.0d;
432 m[off] = (y0 + y0p) / 2.0d;
433 return;
434 }
435 double t = x10p*(y0-y0p) - y10p*(x0-x0p);
436 t /= den;
437 m[off++] = x0 + t*x10;
438 m[off] = y0 + t*y10;
439 }
440
441 private void drawMiter(final double pdx, final double pdy,
442 final double x0, final double y0,
443 final double dx, final double dy,
444 double omx, double omy, double mx, double my,
445 boolean rev)
446 {
447 if ((mx == omx && my == omy) ||
448 (pdx == 0.0d && pdy == 0.0d) ||
449 (dx == 0.0d && dy == 0.0d))
450 {
451 return;
452 }
453
454 if (rev) {
455 omx = -omx;
456 omy = -omy;
457 mx = -mx;
458 my = -my;
459 }
460
461 computeMiter((x0 - pdx) + omx, (y0 - pdy) + omy, x0 + omx, y0 + omy,
462 (dx + x0) + mx, (dy + y0) + my, x0 + mx, y0 + my,
463 miter, 0);
464
465 final double miterX = miter[0];
466 final double miterY = miter[1];
467 double lenSq = (miterX-x0)*(miterX-x0) + (miterY-y0)*(miterY-y0);
468
469 // If the lines are parallel, lenSq will be either NaN or +inf
470 // (actually, I'm not sure if the latter is possible. The important
471 // thing is that -inf is not possible, because lenSq is a square).
472 // For both of those values, the comparison below will fail and
473 // no miter will be drawn, which is correct.
474 if (lenSq < miterLimitSq) {
475 emitLineTo(miterX, miterY, rev);
476 }
477 }
478
479 @Override
480 public void moveTo(final double x0, final double y0) {
481 moveTo(x0, y0, cOutCode);
482 // update starting point:
483 this.sx0 = x0;
484 this.sy0 = y0;
485 this.sdx = 1.0d;
486 this.sdy = 0.0d;
487 this.opened = false;
488 this.capStart = false;
489
490 if (clipRect != null) {
491 final int outcode = DHelpers.outcode(x0, y0, clipRect);
492 this.cOutCode = outcode;
493 this.sOutCode = outcode;
494 }
495 }
496
497 private void moveTo(final double x0, final double y0,
498 final int outcode)
499 {
500 if (prev == MOVE_TO) {
501 this.cx0 = x0;
502 this.cy0 = y0;
503 } else {
504 if (prev == DRAWING_OP_TO) {
505 finish(outcode);
506 }
507 this.prev = MOVE_TO;
508 this.cx0 = x0;
509 this.cy0 = y0;
510 this.cdx = 1.0d;
511 this.cdy = 0.0d;
512 }
513 }
514
515 @Override
516 public void lineTo(final double x1, final double y1) {
517 lineTo(x1, y1, false);
518 }
519
520 private void lineTo(final double x1, final double y1,
521 final boolean force)
522 {
523 final int outcode0 = this.cOutCode;
524 if (!force && clipRect != null) {
525 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
526 this.cOutCode = outcode1;
527
528 // basic rejection criteria
529 if ((outcode0 & outcode1) != 0) {
530 moveTo(x1, y1, outcode0);
531 opened = true;
532 return;
533 }
534 }
535
536 double dx = x1 - cx0;
537 double dy = y1 - cy0;
538 if (dx == 0.0d && dy == 0.0d) {
539 dx = 1.0d;
540 }
541 computeOffset(dx, dy, lineWidth2, offset0);
542 final double mx = offset0[0];
543 final double my = offset0[1];
544
545 drawJoin(cdx, cdy, cx0, cy0, dx, dy, cmx, cmy, mx, my, outcode0);
546
547 emitLineTo(cx0 + mx, cy0 + my);
548 emitLineTo( x1 + mx, y1 + my);
549
550 emitLineToRev(cx0 - mx, cy0 - my);
551 emitLineToRev( x1 - mx, y1 - my);
552
553 this.prev = DRAWING_OP_TO;
735 double x0, double y0,
736 double dx, double dy,
737 double omx, double omy,
738 double mx, double my,
739 final int outcode)
740 {
741 if (prev != DRAWING_OP_TO) {
742 emitMoveTo(x0 + mx, y0 + my);
743 if (!opened) {
744 this.sdx = dx;
745 this.sdy = dy;
746 this.smx = mx;
747 this.smy = my;
748 }
749 } else {
750 final boolean cw = isCW(pdx, pdy, dx, dy);
751 if (outcode == 0) {
752 if (joinStyle == JOIN_MITER) {
753 drawMiter(pdx, pdy, x0, y0, dx, dy, omx, omy, mx, my, cw);
754 } else if (joinStyle == JOIN_ROUND) {
755 drawRoundJoin(x0, y0,
756 omx, omy,
757 mx, my, cw,
758 ROUND_JOIN_THRESHOLD);
759 }
760 }
761 emitLineTo(x0, y0, !cw);
762 }
763 prev = DRAWING_OP_TO;
764 }
765
766 private static boolean within(final double x1, final double y1,
767 final double x2, final double y2,
768 final double ERR)
769 {
770 assert ERR > 0 : "";
771 // compare taxicab distance. ERR will always be small, so using
772 // true distance won't give much benefit
773 return (DHelpers.within(x1, x2, ERR) && // we want to avoid calling Math.abs
774 DHelpers.within(y1, y2, ERR)); // this is just as good.
775 }
776
777 private void getLineOffsets(double x1, double y1,
778 double x2, double y2,
779 double[] left, double[] right) {
780 computeOffset(x2 - x1, y2 - y1, lineWidth2, offset0);
781 final double mx = offset0[0];
782 final double my = offset0[1];
783 left[0] = x1 + mx;
784 left[1] = y1 + my;
785 left[2] = x2 + mx;
786 left[3] = y2 + my;
787 right[0] = x1 - mx;
788 right[1] = y1 - my;
789 right[2] = x2 - mx;
790 right[3] = y2 - my;
791 }
792
793 private int computeOffsetCubic(double[] pts, final int off,
794 double[] leftOff, double[] rightOff)
795 {
796 // if p1=p2 or p3=p4 it means that the derivative at the endpoint
797 // vanishes, which creates problems with computeOffset. Usually
798 // this happens when this stroker object is trying to widen
799 // a curve with a cusp. What happens is that curveTo splits
800 // the input curve at the cusp, and passes it to this function.
801 // because of inaccuracies in the splitting, we consider points
802 // equal if they're very close to each other.
803 final double x1 = pts[off + 0], y1 = pts[off + 1];
804 final double x2 = pts[off + 2], y2 = pts[off + 3];
805 final double x3 = pts[off + 4], y3 = pts[off + 5];
806 final double x4 = pts[off + 6], y4 = pts[off + 7];
807
808 double dx4 = x4 - x3;
809 double dy4 = y4 - y3;
810 double dx1 = x2 - x1;
811 double dy1 = y2 - y1;
812
813 // if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
814 // in which case ignore if p1 == p2
815 final boolean p1eqp2 = within(x1, y1, x2, y2, 6.0d * Math.ulp(y2));
816 final boolean p3eqp4 = within(x3, y3, x4, y4, 6.0d * Math.ulp(y4));
817 if (p1eqp2 && p3eqp4) {
818 getLineOffsets(x1, y1, x4, y4, leftOff, rightOff);
819 return 4;
820 } else if (p1eqp2) {
821 dx1 = x3 - x1;
822 dy1 = y3 - y1;
823 } else if (p3eqp4) {
824 dx4 = x4 - x2;
825 dy4 = y4 - y2;
826 }
827
828 // if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
829 double dotsq = (dx1 * dx4 + dy1 * dy4);
830 dotsq *= dotsq;
831 double l1sq = dx1 * dx1 + dy1 * dy1, l4sq = dx4 * dx4 + dy4 * dy4;
832 if (DHelpers.within(dotsq, l1sq * l4sq, 4.0d * Math.ulp(dotsq))) {
833 getLineOffsets(x1, y1, x4, y4, leftOff, rightOff);
834 return 4;
835 }
836
837 // What we're trying to do in this function is to approximate an ideal
838 // offset curve (call it I) of the input curve B using a bezier curve Bp.
839 // The constraints I use to get the equations are:
840 //
841 // 1. The computed curve Bp should go through I(0) and I(1). These are
842 // x1p, y1p, x4p, y4p, which are p1p and p4p. We still need to find
843 // 4 variables: the x and y components of p2p and p3p (i.e. x2p, y2p, x3p, y3p).
844 //
845 // 2. Bp should have slope equal in absolute value to I at the endpoints. So,
846 // (by the way, the operator || in the comments below means "aligned with".
847 // It is defined on vectors, so when we say I'(0) || Bp'(0) we mean that
848 // vectors I'(0) and Bp'(0) are aligned, which is the same as saying
849 // that the tangent lines of I and Bp at 0 are parallel. Mathematically
850 // this means (I'(t) || Bp'(t)) <==> (I'(t) = c * Bp'(t)) where c is some
851 // nonzero constant.)
925 two_pi_m_p1_m_p4x = 2.0d * xi - x1p - x4p;
926 two_pi_m_p1_m_p4y = 2.0d * yi - y1p - y4p;
927 c1 = invdet43 * (dy4 * two_pi_m_p1_m_p4x - dx4 * two_pi_m_p1_m_p4y);
928 c2 = invdet43 * (dx1 * two_pi_m_p1_m_p4y - dy1 * two_pi_m_p1_m_p4x);
929
930 x2p = x1p + c1*dx1;
931 y2p = y1p + c1*dy1;
932 x3p = x4p + c2*dx4;
933 y3p = y4p + c2*dy4;
934
935 rightOff[0] = x1p; rightOff[1] = y1p;
936 rightOff[2] = x2p; rightOff[3] = y2p;
937 rightOff[4] = x3p; rightOff[5] = y3p;
938 rightOff[6] = x4p; rightOff[7] = y4p;
939 return 8;
940 }
941
942 // compute offset curves using bezier spline through t=0.5 (i.e.
943 // ComputedCurve(0.5) == IdealParallelCurve(0.5))
944 // return the kind of curve in the right and left arrays.
945 private int computeOffsetQuad(double[] pts, final int off,
946 double[] leftOff, double[] rightOff)
947 {
948 final double x1 = pts[off + 0], y1 = pts[off + 1];
949 final double x2 = pts[off + 2], y2 = pts[off + 3];
950 final double x3 = pts[off + 4], y3 = pts[off + 5];
951
952 final double dx3 = x3 - x2;
953 final double dy3 = y3 - y2;
954 final double dx1 = x2 - x1;
955 final double dy1 = y2 - y1;
956
957 // if p1=p2 or p3=p4 it means that the derivative at the endpoint
958 // vanishes, which creates problems with computeOffset. Usually
959 // this happens when this stroker object is trying to widen
960 // a curve with a cusp. What happens is that curveTo splits
961 // the input curve at the cusp, and passes it to this function.
962 // because of inaccuracies in the splitting, we consider points
963 // equal if they're very close to each other.
964
965 // if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
966 // in which case ignore.
967 final boolean p1eqp2 = within(x1, y1, x2, y2, 6.0d * Math.ulp(y2));
968 final boolean p2eqp3 = within(x2, y2, x3, y3, 6.0d * Math.ulp(y3));
969 if (p1eqp2 || p2eqp3) {
970 getLineOffsets(x1, y1, x3, y3, leftOff, rightOff);
971 return 4;
972 }
973
974 // if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
975 double dotsq = (dx1 * dx3 + dy1 * dy3);
976 dotsq *= dotsq;
977 double l1sq = dx1 * dx1 + dy1 * dy1, l3sq = dx3 * dx3 + dy3 * dy3;
978 if (DHelpers.within(dotsq, l1sq * l3sq, 4.0d * Math.ulp(dotsq))) {
979 getLineOffsets(x1, y1, x3, y3, leftOff, rightOff);
980 return 4;
981 }
982
983 // this computes the offsets at t=0, 0.5, 1, using the property that
984 // for any bezier curve the vectors p2-p1 and p4-p3 are parallel to
985 // the (dx/dt, dy/dt) vectors at the endpoints.
986 computeOffset(dx1, dy1, lineWidth2, offset0);
987 computeOffset(dx3, dy3, lineWidth2, offset1);
988
989 double x1p = x1 + offset0[0]; // start
990 double y1p = y1 + offset0[1]; // point
991 double x3p = x3 + offset1[0]; // end
992 double y3p = y3 + offset1[1]; // point
993 safeComputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, leftOff, 2);
994 leftOff[0] = x1p; leftOff[1] = y1p;
995 leftOff[4] = x3p; leftOff[5] = y3p;
996
997 x1p = x1 - offset0[0]; y1p = y1 - offset0[1];
998 x3p = x3 - offset1[0]; y3p = y3 - offset1[1];
999 safeComputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, rightOff, 2);
1000 rightOff[0] = x1p; rightOff[1] = y1p;
1001 rightOff[4] = x3p; rightOff[5] = y3p;
1002 return 6;
1003 }
1004
1005 // finds values of t where the curve in pts should be subdivided in order
1006 // to get good offset curves a distance of w away from the middle curve.
1007 // Stores the points in ts, and returns how many of them there were.
1008 private static int findSubdivPoints(final DCurve c, double[] pts, double[] ts,
1009 final int type, final double w)
1010 {
1011 final double x12 = pts[2] - pts[0];
1012 final double y12 = pts[3] - pts[1];
1013 // if the curve is already parallel to either axis we gain nothing
1014 // from rotating it.
1015 if (y12 != 0.0d && x12 != 0.0d) {
1016 // we rotate it so that the first vector in the control polygon is
1017 // parallel to the x-axis. This will ensure that rotated quarter
1018 // circles won't be subdivided.
1019 final double hypot = Math.sqrt(x12 * x12 + y12 * y12);
1020 final double cos = x12 / hypot;
1021 final double sin = y12 / hypot;
1022 final double x1 = cos * pts[0] + sin * pts[1];
1023 final double y1 = cos * pts[1] - sin * pts[0];
1024 final double x2 = cos * pts[2] + sin * pts[3];
1025 final double y2 = cos * pts[3] - sin * pts[2];
1026 final double x3 = cos * pts[4] + sin * pts[5];
1027 final double y3 = cos * pts[5] - sin * pts[4];
1028
1029 switch(type) {
1030 case 8:
1031 final double x4 = cos * pts[6] + sin * pts[7];
1032 final double y4 = cos * pts[7] - sin * pts[6];
1033 c.set(x1, y1, x2, y2, x3, y3, x4, y4);
1034 break;
1035 case 6:
1036 c.set(x1, y1, x2, y2, x3, y3);
1037 break;
1038 default:
1039 }
1040 } else {
1041 c.set(pts, type);
1042 }
1043
1044 int ret = 0;
1045 // we subdivide at values of t such that the remaining rotated
1046 // curves are monotonic in x and y.
1047 ret += c.dxRoots(ts, ret);
1048 ret += c.dyRoots(ts, ret);
1049 // subdivide at inflection points.
1050 if (type == 8) {
1051 // quadratic curves can't have inflection points
1052 ret += c.infPoints(ts, ret);
1053 }
1054
1055 // now we must subdivide at points where one of the offset curves will have
1056 // a cusp. This happens at ts where the radius of curvature is equal to w.
1057 ret += c.rootsOfROCMinusW(ts, ret, w, 0.0001d);
1058
1059 ret = DHelpers.filterOutNotInAB(ts, 0, ret, 0.0001d, 0.9999d);
1060 DHelpers.isort(ts, 0, ret);
1061 return ret;
1062 }
1063
1064 @Override
1065 public void curveTo(final double x1, final double y1,
1066 final double x2, final double y2,
1067 final double x3, final double y3)
1068 {
1069 final int outcode0 = this.cOutCode;
1070 if (clipRect != null) {
1071 final int outcode3 = DHelpers.outcode(x3, y3, clipRect);
1072 this.cOutCode = outcode3;
1073
1074 if ((outcode0 & outcode3) != 0) {
1075 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
1076 final int outcode2 = DHelpers.outcode(x2, y2, clipRect);
1077
1078 // basic rejection criteria
1079 if ((outcode0 & outcode1 & outcode2 & outcode3) != 0) {
1080 moveTo(x3, y3, outcode0);
1081 opened = true;
1082 return;
1083 }
1084 }
1085 }
1086
1087 final double[] mid = middle;
1088
1089 mid[0] = cx0; mid[1] = cy0;
1090 mid[2] = x1; mid[3] = y1;
1091 mid[4] = x2; mid[5] = y2;
1092 mid[6] = x3; mid[7] = y3;
1093
1094 // need these so we can update the state at the end of this method
1095 final double xf = x3, yf = y3;
1096 double dxs = mid[2] - mid[0];
1097 double dys = mid[3] - mid[1];
1098 double dxf = mid[6] - mid[4];
1099 double dyf = mid[7] - mid[5];
1100
1101 boolean p1eqp2 = (dxs == 0.0d && dys == 0.0d);
1102 boolean p3eqp4 = (dxf == 0.0d && dyf == 0.0d);
1103 if (p1eqp2) {
1104 dxs = mid[4] - mid[0];
1105 dys = mid[5] - mid[1];
1106 if (dxs == 0.0d && dys == 0.0d) {
1107 dxs = mid[6] - mid[0];
1108 dys = mid[7] - mid[1];
1109 }
1110 }
1111 if (p3eqp4) {
1112 dxf = mid[6] - mid[2];
1113 dyf = mid[7] - mid[3];
1114 if (dxf == 0.0d && dyf == 0.0d) {
1115 dxf = mid[6] - mid[0];
1116 dyf = mid[7] - mid[1];
1117 }
1118 }
1119 if (dxs == 0.0d && dys == 0.0d) {
1120 // this happens if the "curve" is just a point
1121 // fix outcode0 for lineTo() call:
1122 if (clipRect != null) {
1123 this.cOutCode = outcode0;
1124 }
1125 lineTo(mid[0], mid[1]);
1126 return;
1127 }
1128
1129 // if these vectors are too small, normalize them, to avoid future
1130 // precision problems.
1131 if (Math.abs(dxs) < 0.1d && Math.abs(dys) < 0.1d) {
1132 double len = Math.sqrt(dxs*dxs + dys*dys);
1133 dxs /= len;
1134 dys /= len;
1135 }
1136 if (Math.abs(dxf) < 0.1d && Math.abs(dyf) < 0.1d) {
1137 double len = Math.sqrt(dxf*dxf + dyf*dyf);
1138 dxf /= len;
1139 dyf /= len;
1140 }
1141
1142 computeOffset(dxs, dys, lineWidth2, offset0);
1143 drawJoin(cdx, cdy, cx0, cy0, dxs, dys, cmx, cmy, offset0[0], offset0[1], outcode0);
1144
1145 final int nSplits = findSubdivPoints(curve, mid, subdivTs, 8, lineWidth2);
1146
1147 double prevT = 0.0d;
1148 for (int i = 0, off = 0; i < nSplits; i++, off += 6) {
1149 final double t = subdivTs[i];
1150 DHelpers.subdivideCubicAt((t - prevT) / (1.0d - prevT),
1151 mid, off, mid, off, mid, off + 6);
1152 prevT = t;
1153 }
1154
1155 final double[] l = lp;
1156 final double[] r = rp;
1157
1158 int kind = 0;
1159 for (int i = 0, off = 0; i <= nSplits; i++, off += 6) {
1160 kind = computeOffsetCubic(mid, off, l, r);
1161
1162 emitLineTo(l[0], l[1]);
1163
1164 switch(kind) {
1165 case 8:
1166 emitCurveTo(l[2], l[3], l[4], l[5], l[6], l[7]);
1167 emitCurveToRev(r[0], r[1], r[2], r[3], r[4], r[5]);
1168 break;
1169 case 4:
1170 emitLineTo(l[2], l[3]);
1171 emitLineToRev(r[0], r[1]);
1172 break;
1173 default:
1174 }
1175 emitLineToRev(r[kind - 2], r[kind - 1]);
1176 }
1177
1178 this.prev = DRAWING_OP_TO;
1179 this.cx0 = xf;
1180 this.cy0 = yf;
1181 this.cdx = dxf;
1182 this.cdy = dyf;
1183 this.cmx = (l[kind - 2] - r[kind - 2]) / 2.0d;
1184 this.cmy = (l[kind - 1] - r[kind - 1]) / 2.0d;
1185 }
1186
1187 @Override
1188 public void quadTo(final double x1, final double y1,
1189 final double x2, final double y2)
1190 {
1191 final int outcode0 = this.cOutCode;
1192 if (clipRect != null) {
1193 final int outcode2 = DHelpers.outcode(x2, y2, clipRect);
1194 this.cOutCode = outcode2;
1195
1196 if ((outcode0 & outcode2) != 0) {
1197 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
1198
1199 // basic rejection criteria
1200 if ((outcode0 & outcode1 & outcode2) != 0) {
1201 moveTo(x2, y2, outcode0);
1202 opened = true;
1203 return;
1204 }
1205 }
1206 }
1207
1208 final double[] mid = middle;
1209
1210 mid[0] = cx0; mid[1] = cy0;
1211 mid[2] = x1; mid[3] = y1;
1212 mid[4] = x2; mid[5] = y2;
1213
1214 // need these so we can update the state at the end of this method
1215 final double xf = x2, yf = y2;
1216 double dxs = mid[2] - mid[0];
1217 double dys = mid[3] - mid[1];
1218 double dxf = mid[4] - mid[2];
1219 double dyf = mid[5] - mid[3];
1220 if ((dxs == 0.0d && dys == 0.0d) || (dxf == 0.0d && dyf == 0.0d)) {
1221 dxs = dxf = mid[4] - mid[0];
1222 dys = dyf = mid[5] - mid[1];
1223 }
1224 if (dxs == 0.0d && dys == 0.0d) {
1225 // this happens if the "curve" is just a point
1226 // fix outcode0 for lineTo() call:
1227 if (clipRect != null) {
1228 this.cOutCode = outcode0;
1229 }
1230 lineTo(mid[0], mid[1]);
1231 return;
1232 }
1233 // if these vectors are too small, normalize them, to avoid future
1234 // precision problems.
1235 if (Math.abs(dxs) < 0.1d && Math.abs(dys) < 0.1d) {
1236 double len = Math.sqrt(dxs*dxs + dys*dys);
1237 dxs /= len;
1238 dys /= len;
1239 }
1240 if (Math.abs(dxf) < 0.1d && Math.abs(dyf) < 0.1d) {
1241 double len = Math.sqrt(dxf*dxf + dyf*dyf);
1242 dxf /= len;
1243 dyf /= len;
1244 }
1245
1246 computeOffset(dxs, dys, lineWidth2, offset0);
1247 drawJoin(cdx, cdy, cx0, cy0, dxs, dys, cmx, cmy, offset0[0], offset0[1], outcode0);
1248
1249 int nSplits = findSubdivPoints(curve, mid, subdivTs, 6, lineWidth2);
1250
1251 double prevt = 0.0d;
1252 for (int i = 0, off = 0; i < nSplits; i++, off += 4) {
1253 final double t = subdivTs[i];
1254 DHelpers.subdivideQuadAt((t - prevt) / (1.0d - prevt),
1255 mid, off, mid, off, mid, off + 4);
1256 prevt = t;
1257 }
1258
1259 final double[] l = lp;
1260 final double[] r = rp;
1261
1262 int kind = 0;
1263 for (int i = 0, off = 0; i <= nSplits; i++, off += 4) {
1264 kind = computeOffsetQuad(mid, off, l, r);
1265
1266 emitLineTo(l[0], l[1]);
1267
1268 switch(kind) {
1269 case 6:
1270 emitQuadTo(l[2], l[3], l[4], l[5]);
1271 emitQuadToRev(r[0], r[1], r[2], r[3]);
1272 break;
1273 case 4:
1274 emitLineTo(l[2], l[3]);
1275 emitLineToRev(r[0], r[1]);
1276 break;
1277 default:
1278 }
1279 emitLineToRev(r[kind - 2], r[kind - 1]);
1280 }
1281
1282 this.prev = DRAWING_OP_TO;
1283 this.cx0 = xf;
1284 this.cy0 = yf;
1285 this.cdx = dxf;
1286 this.cdy = dyf;
1287 this.cmx = (l[kind - 2] - r[kind - 2]) / 2.0d;
1288 this.cmy = (l[kind - 1] - r[kind - 1]) / 2.0d;
1289 }
1290
1291 @Override public long getNativeConsumer() {
1292 throw new InternalError("Stroker doesn't use a native consumer");
1293 }
1294 }
|
1 /*
2 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.java2d.marlin;
27
28 import java.util.Arrays;
29 import sun.java2d.marlin.DHelpers.PolyStack;
30 import sun.java2d.marlin.DTransformingPathConsumer2D.CurveBasicMonotonizer;
31 import sun.java2d.marlin.DTransformingPathConsumer2D.CurveClipSplitter;
32
33 // TODO: some of the arithmetic here is too verbose and prone to hard to
34 // debug typos. We should consider making a small Point/Vector class that
35 // has methods like plus(Point), minus(Point), dot(Point), cross(Point)and such
36 final class DStroker implements DPathConsumer2D, MarlinConst {
37
38 private static final int MOVE_TO = 0;
39 private static final int DRAWING_OP_TO = 1; // ie. curve, line, or quad
40 private static final int CLOSE = 2;
41
42 // round join threshold = 1 subpixel
43 private static final double ERR_JOIN = (1.0f / MIN_SUBPIXELS);
44 private static final double ROUND_JOIN_THRESHOLD = ERR_JOIN * ERR_JOIN;
45
46 // kappa = (4/3) * (SQRT(2) - 1)
47 private static final double C = (4.0d * (Math.sqrt(2.0d) - 1.0d) / 3.0d);
48
49 // SQRT(2)
50 private static final double SQRT_2 = Math.sqrt(2.0d);
51
52 private DPathConsumer2D out;
53
54 private int capStyle;
55 private int joinStyle;
56
57 private double lineWidth2;
58 private double invHalfLineWidth2Sq;
59
60 private final double[] offset0 = new double[2];
61 private final double[] offset1 = new double[2];
62 private final double[] offset2 = new double[2];
63 private final double[] miter = new double[2];
64 private double miterLimitSq;
65
66 private int prev;
67
68 // The starting point of the path, and the slope there.
69 private double sx0, sy0, sdx, sdy;
70 // the current point and the slope there.
71 private double cx0, cy0, cdx, cdy; // c stands for current
72 // vectors that when added to (sx0,sy0) and (cx0,cy0) respectively yield the
73 // first and last points on the left parallel path. Since this path is
74 // parallel, it's slope at any point is parallel to the slope of the
75 // original path (thought they may have different directions), so these
76 // could be computed from sdx,sdy and cdx,cdy (and vice versa), but that
77 // would be error prone and hard to read, so we keep these anyway.
78 private double smx, smy, cmx, cmy;
79
80 private final PolyStack reverse;
81
82 private final double[] lp = new double[8];
83 private final double[] rp = new double[8];
84
85 // per-thread renderer context
86 final DRendererContext rdrCtx;
87
88 // dirty curve
89 final DCurve curve;
90
91 // Bounds of the drawing region, at pixel precision.
92 private double[] clipRect;
93
94 // the outcode of the current point
95 private int cOutCode = 0;
96
97 // the outcode of the starting point
98 private int sOutCode = 0;
99
100 // flag indicating if the path is opened (clipped)
101 private boolean opened = false;
102 // flag indicating if the starting point's cap is done
103 private boolean capStart = false;
104 // flag indicating to monotonize curves
105 private boolean monotonize;
106
107 private boolean subdivide = false;
108 private final CurveClipSplitter curveSplitter;
109
110 /**
111 * Constructs a <code>DStroker</code>.
112 * @param rdrCtx per-thread renderer context
113 */
114 DStroker(final DRendererContext rdrCtx) {
115 this.rdrCtx = rdrCtx;
116
117 this.reverse = (rdrCtx.stats != null) ?
118 new PolyStack(rdrCtx,
119 rdrCtx.stats.stat_str_polystack_types,
120 rdrCtx.stats.stat_str_polystack_curves,
121 rdrCtx.stats.hist_str_polystack_curves,
122 rdrCtx.stats.stat_array_str_polystack_curves,
123 rdrCtx.stats.stat_array_str_polystack_types)
124 : new PolyStack(rdrCtx);
125
126 this.curve = rdrCtx.curve;
127 this.curveSplitter = rdrCtx.curveClipSplitter;
128 }
129
130 /**
131 * Inits the <code>DStroker</code>.
132 *
133 * @param pc2d an output <code>DPathConsumer2D</code>.
134 * @param lineWidth the desired line width in pixels
135 * @param capStyle the desired end cap style, one of
136 * <code>CAP_BUTT</code>, <code>CAP_ROUND</code> or
137 * <code>CAP_SQUARE</code>.
138 * @param joinStyle the desired line join style, one of
139 * <code>JOIN_MITER</code>, <code>JOIN_ROUND</code> or
140 * <code>JOIN_BEVEL</code>.
141 * @param miterLimit the desired miter limit
142 * @param scale scaling factor applied to clip boundaries
143 * @param subdivideCurves true to indicate to subdivide curves, false if dasher does
144 * @return this instance
145 */
146 DStroker init(final DPathConsumer2D pc2d,
147 final double lineWidth,
148 final int capStyle,
149 final int joinStyle,
150 final double miterLimit,
151 final double scale,
152 final boolean subdivideCurves)
153 {
154 this.out = pc2d;
155
156 this.lineWidth2 = lineWidth / 2.0d;
157 this.invHalfLineWidth2Sq = 1.0d / (2.0d * lineWidth2 * lineWidth2);
158 this.monotonize = subdivideCurves;
159
160 this.capStyle = capStyle;
161 this.joinStyle = joinStyle;
162
163 final double limit = miterLimit * lineWidth2;
164 this.miterLimitSq = limit * limit;
165
166 this.prev = CLOSE;
167
168 rdrCtx.stroking = 1;
169
170 if (rdrCtx.doClip) {
171 // Adjust the clipping rectangle with the stroker margin (miter limit, width)
172 double rdrOffX = 0.0d, rdrOffY = 0.0d;
173 double margin = lineWidth2;
174
175 if (capStyle == CAP_SQUARE) {
176 margin *= SQRT_2;
177 }
178 if ((joinStyle == JOIN_MITER) && (margin < limit)) {
179 margin = limit;
180 }
181 if (scale != 1.0d) {
182 margin *= scale;
183 rdrOffX = scale * DRenderer.RDR_OFFSET_X;
184 rdrOffY = scale * DRenderer.RDR_OFFSET_Y;
185 }
186 // add a small rounding error:
187 margin += 1e-3d;
188
189 // bounds as half-open intervals: minX <= x < maxX and minY <= y < maxY
190 // adjust clip rectangle (ymin, ymax, xmin, xmax):
191 final double[] _clipRect = rdrCtx.clipRect;
192 _clipRect[0] -= margin - rdrOffY;
193 _clipRect[1] += margin + rdrOffY;
194 _clipRect[2] -= margin - rdrOffX;
195 _clipRect[3] += margin + rdrOffX;
196 this.clipRect = _clipRect;
197
198 // initialize curve splitter here for stroker & dasher:
199 if (DO_CLIP_SUBDIVIDER) {
200 subdivide = subdivideCurves;
201 // adjust padded clip rectangle:
202 curveSplitter.init();
203 } else {
204 subdivide = false;
205 }
206 } else {
207 this.clipRect = null;
208 this.cOutCode = 0;
209 this.sOutCode = 0;
210 }
211 return this; // fluent API
212 }
213
214 void disableClipping() {
215 this.clipRect = null;
216 this.cOutCode = 0;
217 this.sOutCode = 0;
218 }
219
220 /**
221 * Disposes this stroker:
222 * clean up before reusing this instance
223 */
224 void dispose() {
225 reverse.dispose();
226
227 opened = false;
228 capStart = false;
229
230 if (DO_CLEAN_DIRTY) {
231 // Force zero-fill dirty arrays:
232 Arrays.fill(offset0, 0.0d);
233 Arrays.fill(offset1, 0.0d);
234 Arrays.fill(offset2, 0.0d);
235 Arrays.fill(miter, 0.0d);
236 Arrays.fill(lp, 0.0d);
237 Arrays.fill(rp, 0.0d);
238 }
239 }
240
241 private static void computeOffset(final double lx, final double ly,
242 final double w, final double[] m)
243 {
244 double len = lx*lx + ly*ly;
245 if (len == 0.0d) {
246 m[0] = 0.0d;
247 m[1] = 0.0d;
248 } else {
249 len = Math.sqrt(len);
250 m[0] = (ly * w) / len;
251 m[1] = -(lx * w) / len;
252 }
253 }
254
255 // Returns true if the vectors (dx1, dy1) and (dx2, dy2) are
256 // clockwise (if dx1,dy1 needs to be rotated clockwise to close
257 // the smallest angle between it and dx2,dy2).
258 // This is equivalent to detecting whether a point q is on the right side
259 // of a line passing through points p1, p2 where p2 = p1+(dx1,dy1) and
260 // q = p2+(dx2,dy2), which is the same as saying p1, p2, q are in a
261 // clockwise order.
262 // NOTE: "clockwise" here assumes coordinates with 0,0 at the bottom left.
263 private static boolean isCW(final double dx1, final double dy1,
264 final double dx2, final double dy2)
265 {
266 return dx1 * dy2 <= dy1 * dx2;
267 }
268
269 private void mayDrawRoundJoin(double cx, double cy,
270 double omx, double omy,
271 double mx, double my,
272 boolean rev)
273 {
274 if ((omx == 0.0d && omy == 0.0d) || (mx == 0.0d && my == 0.0d)) {
275 return;
276 }
277
278 final double domx = omx - mx;
279 final double domy = omy - my;
280 final double lenSq = domx*domx + domy*domy;
281
282 if (lenSq < ROUND_JOIN_THRESHOLD) {
283 return;
284 }
285
286 if (rev) {
287 omx = -omx;
288 omy = -omy;
289 mx = -mx;
290 my = -my;
291 }
292 drawRoundJoin(cx, cy, omx, omy, mx, my, rev);
293 }
294
295 private void drawRoundJoin(double cx, double cy,
296 double omx, double omy,
297 double mx, double my,
298 boolean rev)
299 {
300 // The sign of the dot product of mx,my and omx,omy is equal to the
301 // the sign of the cosine of ext
302 // (ext is the angle between omx,omy and mx,my).
303 final double cosext = omx * mx + omy * my;
304 // If it is >=0, we know that abs(ext) is <= 90 degrees, so we only
305 // need 1 curve to approximate the circle section that joins omx,omy
306 // and mx,my.
307 final int numCurves = (cosext >= 0.0d) ? 1 : 2;
308
309 switch (numCurves) {
310 case 1:
311 drawBezApproxForArc(cx, cy, omx, omy, mx, my, rev);
312 break;
383 emitCurveTo(x1, y1, x2, y2, x3, y3, x4, y4, rev);
384 }
385
386 private void drawRoundCap(double cx, double cy, double mx, double my) {
387 final double Cmx = C * mx;
388 final double Cmy = C * my;
389 emitCurveTo(cx + mx - Cmy, cy + my + Cmx,
390 cx - my + Cmx, cy + mx + Cmy,
391 cx - my, cy + mx);
392 emitCurveTo(cx - my - Cmx, cy + mx - Cmy,
393 cx - mx - Cmy, cy - my + Cmx,
394 cx - mx, cy - my);
395 }
396
397 // Return the intersection point of the lines (x0, y0) -> (x1, y1)
398 // and (x0p, y0p) -> (x1p, y1p) in m[off] and m[off+1]
399 private static void computeMiter(final double x0, final double y0,
400 final double x1, final double y1,
401 final double x0p, final double y0p,
402 final double x1p, final double y1p,
403 final double[] m)
404 {
405 double x10 = x1 - x0;
406 double y10 = y1 - y0;
407 double x10p = x1p - x0p;
408 double y10p = y1p - y0p;
409
410 // if this is 0, the lines are parallel. If they go in the
411 // same direction, there is no intersection so m[off] and
412 // m[off+1] will contain infinity, so no miter will be drawn.
413 // If they go in the same direction that means that the start of the
414 // current segment and the end of the previous segment have the same
415 // tangent, in which case this method won't even be involved in
416 // miter drawing because it won't be called by drawMiter (because
417 // (mx == omx && my == omy) will be true, and drawMiter will return
418 // immediately).
419 double den = x10*y10p - x10p*y10;
420 double t = x10p*(y0-y0p) - y10p*(x0-x0p);
421 t /= den;
422 m[0] = x0 + t*x10;
423 m[1] = y0 + t*y10;
424 }
425
426 // Return the intersection point of the lines (x0, y0) -> (x1, y1)
427 // and (x0p, y0p) -> (x1p, y1p) in m[off] and m[off+1]
428 private static void safeComputeMiter(final double x0, final double y0,
429 final double x1, final double y1,
430 final double x0p, final double y0p,
431 final double x1p, final double y1p,
432 final double[] m)
433 {
434 double x10 = x1 - x0;
435 double y10 = y1 - y0;
436 double x10p = x1p - x0p;
437 double y10p = y1p - y0p;
438
439 // if this is 0, the lines are parallel. If they go in the
440 // same direction, there is no intersection so m[off] and
441 // m[off+1] will contain infinity, so no miter will be drawn.
442 // If they go in the same direction that means that the start of the
443 // current segment and the end of the previous segment have the same
444 // tangent, in which case this method won't even be involved in
445 // miter drawing because it won't be called by drawMiter (because
446 // (mx == omx && my == omy) will be true, and drawMiter will return
447 // immediately).
448 double den = x10*y10p - x10p*y10;
449 if (den == 0.0d) {
450 m[2] = (x0 + x0p) / 2.0d;
451 m[3] = (y0 + y0p) / 2.0d;
452 } else {
453 double t = x10p*(y0-y0p) - y10p*(x0-x0p);
454 t /= den;
455 m[2] = x0 + t*x10;
456 m[3] = y0 + t*y10;
457 }
458 }
459
460 private void drawMiter(final double pdx, final double pdy,
461 final double x0, final double y0,
462 final double dx, final double dy,
463 double omx, double omy,
464 double mx, double my,
465 boolean rev)
466 {
467 if ((mx == omx && my == omy) ||
468 (pdx == 0.0d && pdy == 0.0d) ||
469 (dx == 0.0d && dy == 0.0d))
470 {
471 return;
472 }
473
474 if (rev) {
475 omx = -omx;
476 omy = -omy;
477 mx = -mx;
478 my = -my;
479 }
480
481 computeMiter((x0 - pdx) + omx, (y0 - pdy) + omy, x0 + omx, y0 + omy,
482 (dx + x0) + mx, (dy + y0) + my, x0 + mx, y0 + my, miter);
483
484 final double miterX = miter[0];
485 final double miterY = miter[1];
486 double lenSq = (miterX-x0)*(miterX-x0) + (miterY-y0)*(miterY-y0);
487
488 // If the lines are parallel, lenSq will be either NaN or +inf
489 // (actually, I'm not sure if the latter is possible. The important
490 // thing is that -inf is not possible, because lenSq is a square).
491 // For both of those values, the comparison below will fail and
492 // no miter will be drawn, which is correct.
493 if (lenSq < miterLimitSq) {
494 emitLineTo(miterX, miterY, rev);
495 }
496 }
497
498 @Override
499 public void moveTo(final double x0, final double y0) {
500 _moveTo(x0, y0, cOutCode);
501 // update starting point:
502 this.sx0 = x0;
503 this.sy0 = y0;
504 this.sdx = 1.0d;
505 this.sdy = 0.0d;
506 this.opened = false;
507 this.capStart = false;
508
509 if (clipRect != null) {
510 final int outcode = DHelpers.outcode(x0, y0, clipRect);
511 this.cOutCode = outcode;
512 this.sOutCode = outcode;
513 }
514 }
515
516 private void _moveTo(final double x0, final double y0,
517 final int outcode)
518 {
519 if (prev == MOVE_TO) {
520 this.cx0 = x0;
521 this.cy0 = y0;
522 } else {
523 if (prev == DRAWING_OP_TO) {
524 finish(outcode);
525 }
526 this.prev = MOVE_TO;
527 this.cx0 = x0;
528 this.cy0 = y0;
529 this.cdx = 1.0d;
530 this.cdy = 0.0d;
531 }
532 }
533
534 @Override
535 public void lineTo(final double x1, final double y1) {
536 lineTo(x1, y1, false);
537 }
538
539 private void lineTo(final double x1, final double y1,
540 final boolean force)
541 {
542 final int outcode0 = this.cOutCode;
543
544 if (!force && clipRect != null) {
545 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
546
547 // Should clip
548 final int orCode = (outcode0 | outcode1);
549 if (orCode != 0) {
550 final int sideCode = outcode0 & outcode1;
551
552 // basic rejection criteria:
553 if (sideCode == 0) {
554 // ovelap clip:
555 if (subdivide) {
556 // avoid reentrance
557 subdivide = false;
558 // subdivide curve => callback with subdivided parts:
559 boolean ret = curveSplitter.splitLine(cx0, cy0, x1, y1,
560 orCode, this);
561 // reentrance is done:
562 subdivide = true;
563 if (ret) {
564 return;
565 }
566 }
567 // already subdivided so render it
568 } else {
569 this.cOutCode = outcode1;
570 _moveTo(x1, y1, outcode0);
571 opened = true;
572 return;
573 }
574 }
575
576 this.cOutCode = outcode1;
577 }
578
579 double dx = x1 - cx0;
580 double dy = y1 - cy0;
581 if (dx == 0.0d && dy == 0.0d) {
582 dx = 1.0d;
583 }
584 computeOffset(dx, dy, lineWidth2, offset0);
585 final double mx = offset0[0];
586 final double my = offset0[1];
587
588 drawJoin(cdx, cdy, cx0, cy0, dx, dy, cmx, cmy, mx, my, outcode0);
589
590 emitLineTo(cx0 + mx, cy0 + my);
591 emitLineTo( x1 + mx, y1 + my);
592
593 emitLineToRev(cx0 - mx, cy0 - my);
594 emitLineToRev( x1 - mx, y1 - my);
595
596 this.prev = DRAWING_OP_TO;
778 double x0, double y0,
779 double dx, double dy,
780 double omx, double omy,
781 double mx, double my,
782 final int outcode)
783 {
784 if (prev != DRAWING_OP_TO) {
785 emitMoveTo(x0 + mx, y0 + my);
786 if (!opened) {
787 this.sdx = dx;
788 this.sdy = dy;
789 this.smx = mx;
790 this.smy = my;
791 }
792 } else {
793 final boolean cw = isCW(pdx, pdy, dx, dy);
794 if (outcode == 0) {
795 if (joinStyle == JOIN_MITER) {
796 drawMiter(pdx, pdy, x0, y0, dx, dy, omx, omy, mx, my, cw);
797 } else if (joinStyle == JOIN_ROUND) {
798 mayDrawRoundJoin(x0, y0, omx, omy, mx, my, cw);
799 }
800 }
801 emitLineTo(x0, y0, !cw);
802 }
803 prev = DRAWING_OP_TO;
804 }
805
806 private static boolean within(final double x1, final double y1,
807 final double x2, final double y2,
808 final double err)
809 {
810 assert err > 0 : "";
811 // compare taxicab distance. ERR will always be small, so using
812 // true distance won't give much benefit
813 return (DHelpers.within(x1, x2, err) && // we want to avoid calling Math.abs
814 DHelpers.within(y1, y2, err)); // this is just as good.
815 }
816
817 private void getLineOffsets(final double x1, final double y1,
818 final double x2, final double y2,
819 final double[] left, final double[] right)
820 {
821 computeOffset(x2 - x1, y2 - y1, lineWidth2, offset0);
822 final double mx = offset0[0];
823 final double my = offset0[1];
824 left[0] = x1 + mx;
825 left[1] = y1 + my;
826 left[2] = x2 + mx;
827 left[3] = y2 + my;
828
829 right[0] = x1 - mx;
830 right[1] = y1 - my;
831 right[2] = x2 - mx;
832 right[3] = y2 - my;
833 }
834
835 private int computeOffsetCubic(final double[] pts, final int off,
836 final double[] leftOff,
837 final double[] rightOff)
838 {
839 // if p1=p2 or p3=p4 it means that the derivative at the endpoint
840 // vanishes, which creates problems with computeOffset. Usually
841 // this happens when this stroker object is trying to widen
842 // a curve with a cusp. What happens is that curveTo splits
843 // the input curve at the cusp, and passes it to this function.
844 // because of inaccuracies in the splitting, we consider points
845 // equal if they're very close to each other.
846 final double x1 = pts[off ], y1 = pts[off + 1];
847 final double x2 = pts[off + 2], y2 = pts[off + 3];
848 final double x3 = pts[off + 4], y3 = pts[off + 5];
849 final double x4 = pts[off + 6], y4 = pts[off + 7];
850
851 double dx4 = x4 - x3;
852 double dy4 = y4 - y3;
853 double dx1 = x2 - x1;
854 double dy1 = y2 - y1;
855
856 // if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
857 // in which case ignore if p1 == p2
858 final boolean p1eqp2 = within(x1, y1, x2, y2, 6.0d * Math.ulp(y2));
859 final boolean p3eqp4 = within(x3, y3, x4, y4, 6.0d * Math.ulp(y4));
860
861 if (p1eqp2 && p3eqp4) {
862 getLineOffsets(x1, y1, x4, y4, leftOff, rightOff);
863 return 4;
864 } else if (p1eqp2) {
865 dx1 = x3 - x1;
866 dy1 = y3 - y1;
867 } else if (p3eqp4) {
868 dx4 = x4 - x2;
869 dy4 = y4 - y2;
870 }
871
872 // if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
873 double dotsq = (dx1 * dx4 + dy1 * dy4);
874 dotsq *= dotsq;
875 double l1sq = dx1 * dx1 + dy1 * dy1, l4sq = dx4 * dx4 + dy4 * dy4;
876
877 if (DHelpers.within(dotsq, l1sq * l4sq, 4.0d * Math.ulp(dotsq))) {
878 getLineOffsets(x1, y1, x4, y4, leftOff, rightOff);
879 return 4;
880 }
881
882 // What we're trying to do in this function is to approximate an ideal
883 // offset curve (call it I) of the input curve B using a bezier curve Bp.
884 // The constraints I use to get the equations are:
885 //
886 // 1. The computed curve Bp should go through I(0) and I(1). These are
887 // x1p, y1p, x4p, y4p, which are p1p and p4p. We still need to find
888 // 4 variables: the x and y components of p2p and p3p (i.e. x2p, y2p, x3p, y3p).
889 //
890 // 2. Bp should have slope equal in absolute value to I at the endpoints. So,
891 // (by the way, the operator || in the comments below means "aligned with".
892 // It is defined on vectors, so when we say I'(0) || Bp'(0) we mean that
893 // vectors I'(0) and Bp'(0) are aligned, which is the same as saying
894 // that the tangent lines of I and Bp at 0 are parallel. Mathematically
895 // this means (I'(t) || Bp'(t)) <==> (I'(t) = c * Bp'(t)) where c is some
896 // nonzero constant.)
970 two_pi_m_p1_m_p4x = 2.0d * xi - x1p - x4p;
971 two_pi_m_p1_m_p4y = 2.0d * yi - y1p - y4p;
972 c1 = invdet43 * (dy4 * two_pi_m_p1_m_p4x - dx4 * two_pi_m_p1_m_p4y);
973 c2 = invdet43 * (dx1 * two_pi_m_p1_m_p4y - dy1 * two_pi_m_p1_m_p4x);
974
975 x2p = x1p + c1*dx1;
976 y2p = y1p + c1*dy1;
977 x3p = x4p + c2*dx4;
978 y3p = y4p + c2*dy4;
979
980 rightOff[0] = x1p; rightOff[1] = y1p;
981 rightOff[2] = x2p; rightOff[3] = y2p;
982 rightOff[4] = x3p; rightOff[5] = y3p;
983 rightOff[6] = x4p; rightOff[7] = y4p;
984 return 8;
985 }
986
987 // compute offset curves using bezier spline through t=0.5 (i.e.
988 // ComputedCurve(0.5) == IdealParallelCurve(0.5))
989 // return the kind of curve in the right and left arrays.
990 private int computeOffsetQuad(final double[] pts, final int off,
991 final double[] leftOff,
992 final double[] rightOff)
993 {
994 final double x1 = pts[off ], y1 = pts[off + 1];
995 final double x2 = pts[off + 2], y2 = pts[off + 3];
996 final double x3 = pts[off + 4], y3 = pts[off + 5];
997
998 final double dx3 = x3 - x2;
999 final double dy3 = y3 - y2;
1000 final double dx1 = x2 - x1;
1001 final double dy1 = y2 - y1;
1002
1003 // if p1=p2 or p3=p4 it means that the derivative at the endpoint
1004 // vanishes, which creates problems with computeOffset. Usually
1005 // this happens when this stroker object is trying to widen
1006 // a curve with a cusp. What happens is that curveTo splits
1007 // the input curve at the cusp, and passes it to this function.
1008 // because of inaccuracies in the splitting, we consider points
1009 // equal if they're very close to each other.
1010
1011 // if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
1012 // in which case ignore.
1013 final boolean p1eqp2 = within(x1, y1, x2, y2, 6.0d * Math.ulp(y2));
1014 final boolean p2eqp3 = within(x2, y2, x3, y3, 6.0d * Math.ulp(y3));
1015
1016 if (p1eqp2 || p2eqp3) {
1017 getLineOffsets(x1, y1, x3, y3, leftOff, rightOff);
1018 return 4;
1019 }
1020
1021 // if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
1022 double dotsq = (dx1 * dx3 + dy1 * dy3);
1023 dotsq *= dotsq;
1024 double l1sq = dx1 * dx1 + dy1 * dy1, l3sq = dx3 * dx3 + dy3 * dy3;
1025
1026 if (DHelpers.within(dotsq, l1sq * l3sq, 4.0d * Math.ulp(dotsq))) {
1027 getLineOffsets(x1, y1, x3, y3, leftOff, rightOff);
1028 return 4;
1029 }
1030
1031 // this computes the offsets at t=0, 0.5, 1, using the property that
1032 // for any bezier curve the vectors p2-p1 and p4-p3 are parallel to
1033 // the (dx/dt, dy/dt) vectors at the endpoints.
1034 computeOffset(dx1, dy1, lineWidth2, offset0);
1035 computeOffset(dx3, dy3, lineWidth2, offset1);
1036
1037 double x1p = x1 + offset0[0]; // start
1038 double y1p = y1 + offset0[1]; // point
1039 double x3p = x3 + offset1[0]; // end
1040 double y3p = y3 + offset1[1]; // point
1041 safeComputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, leftOff);
1042 leftOff[0] = x1p; leftOff[1] = y1p;
1043 leftOff[4] = x3p; leftOff[5] = y3p;
1044
1045 x1p = x1 - offset0[0]; y1p = y1 - offset0[1];
1046 x3p = x3 - offset1[0]; y3p = y3 - offset1[1];
1047 safeComputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, rightOff);
1048 rightOff[0] = x1p; rightOff[1] = y1p;
1049 rightOff[4] = x3p; rightOff[5] = y3p;
1050 return 6;
1051 }
1052
1053 @Override
1054 public void curveTo(final double x1, final double y1,
1055 final double x2, final double y2,
1056 final double x3, final double y3)
1057 {
1058 final int outcode0 = this.cOutCode;
1059
1060 if (clipRect != null) {
1061 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
1062 final int outcode2 = DHelpers.outcode(x2, y2, clipRect);
1063 final int outcode3 = DHelpers.outcode(x3, y3, clipRect);
1064
1065 // Should clip
1066 final int orCode = (outcode0 | outcode1 | outcode2 | outcode3);
1067 if (orCode != 0) {
1068 final int sideCode = outcode0 & outcode1 & outcode2 & outcode3;
1069
1070 // basic rejection criteria:
1071 if (sideCode == 0) {
1072 // ovelap clip:
1073 if (subdivide) {
1074 // avoid reentrance
1075 subdivide = false;
1076 // subdivide curve => callback with subdivided parts:
1077 boolean ret = curveSplitter.splitCurve(cx0, cy0, x1, y1,
1078 x2, y2, x3, y3,
1079 orCode, this);
1080 // reentrance is done:
1081 subdivide = true;
1082 if (ret) {
1083 return;
1084 }
1085 }
1086 // already subdivided so render it
1087 } else {
1088 this.cOutCode = outcode3;
1089 _moveTo(x3, y3, outcode0);
1090 opened = true;
1091 return;
1092 }
1093 }
1094
1095 this.cOutCode = outcode3;
1096 }
1097 _curveTo(x1, y1, x2, y2, x3, y3, outcode0);
1098 }
1099
1100 private void _curveTo(final double x1, final double y1,
1101 final double x2, final double y2,
1102 final double x3, final double y3,
1103 final int outcode0)
1104 {
1105 // need these so we can update the state at the end of this method
1106 double dxs = x1 - cx0;
1107 double dys = y1 - cy0;
1108 double dxf = x3 - x2;
1109 double dyf = y3 - y2;
1110
1111 if ((dxs == 0.0d) && (dys == 0.0d)) {
1112 dxs = x2 - cx0;
1113 dys = y2 - cy0;
1114 if ((dxs == 0.0d) && (dys == 0.0d)) {
1115 dxs = x3 - cx0;
1116 dys = y3 - cy0;
1117 }
1118 }
1119 if ((dxf == 0.0d) && (dyf == 0.0d)) {
1120 dxf = x3 - x1;
1121 dyf = y3 - y1;
1122 if ((dxf == 0.0d) && (dyf == 0.0d)) {
1123 dxf = x3 - cx0;
1124 dyf = y3 - cy0;
1125 }
1126 }
1127 if ((dxs == 0.0d) && (dys == 0.0d)) {
1128 // this happens if the "curve" is just a point
1129 // fix outcode0 for lineTo() call:
1130 if (clipRect != null) {
1131 this.cOutCode = outcode0;
1132 }
1133 lineTo(cx0, cy0);
1134 return;
1135 }
1136
1137 // if these vectors are too small, normalize them, to avoid future
1138 // precision problems.
1139 if (Math.abs(dxs) < 0.1d && Math.abs(dys) < 0.1d) {
1140 final double len = Math.sqrt(dxs * dxs + dys * dys);
1141 dxs /= len;
1142 dys /= len;
1143 }
1144 if (Math.abs(dxf) < 0.1d && Math.abs(dyf) < 0.1d) {
1145 final double len = Math.sqrt(dxf * dxf + dyf * dyf);
1146 dxf /= len;
1147 dyf /= len;
1148 }
1149
1150 computeOffset(dxs, dys, lineWidth2, offset0);
1151 drawJoin(cdx, cdy, cx0, cy0, dxs, dys, cmx, cmy, offset0[0], offset0[1], outcode0);
1152
1153 int nSplits = 0;
1154 final double[] mid;
1155 final double[] l = lp;
1156
1157 if (monotonize) {
1158 // monotonize curve:
1159 final CurveBasicMonotonizer monotonizer
1160 = rdrCtx.monotonizer.curve(cx0, cy0, x1, y1, x2, y2, x3, y3);
1161
1162 nSplits = monotonizer.nbSplits;
1163 mid = monotonizer.middle;
1164 } else {
1165 // use left instead:
1166 mid = l;
1167 mid[0] = cx0; mid[1] = cy0;
1168 mid[2] = x1; mid[3] = y1;
1169 mid[4] = x2; mid[5] = y2;
1170 mid[6] = x3; mid[7] = y3;
1171 }
1172 final double[] r = rp;
1173
1174 int kind = 0;
1175 for (int i = 0, off = 0; i <= nSplits; i++, off += 6) {
1176 kind = computeOffsetCubic(mid, off, l, r);
1177
1178 emitLineTo(l[0], l[1]);
1179
1180 switch(kind) {
1181 case 8:
1182 emitCurveTo(l[2], l[3], l[4], l[5], l[6], l[7]);
1183 emitCurveToRev(r[0], r[1], r[2], r[3], r[4], r[5]);
1184 break;
1185 case 4:
1186 emitLineTo(l[2], l[3]);
1187 emitLineToRev(r[0], r[1]);
1188 break;
1189 default:
1190 }
1191 emitLineToRev(r[kind - 2], r[kind - 1]);
1192 }
1193
1194 this.prev = DRAWING_OP_TO;
1195 this.cx0 = x3;
1196 this.cy0 = y3;
1197 this.cdx = dxf;
1198 this.cdy = dyf;
1199 this.cmx = (l[kind - 2] - r[kind - 2]) / 2.0d;
1200 this.cmy = (l[kind - 1] - r[kind - 1]) / 2.0d;
1201 }
1202
1203 @Override
1204 public void quadTo(final double x1, final double y1,
1205 final double x2, final double y2)
1206 {
1207 final int outcode0 = this.cOutCode;
1208
1209 if (clipRect != null) {
1210 final int outcode1 = DHelpers.outcode(x1, y1, clipRect);
1211 final int outcode2 = DHelpers.outcode(x2, y2, clipRect);
1212
1213 // Should clip
1214 final int orCode = (outcode0 | outcode1 | outcode2);
1215 if (orCode != 0) {
1216 final int sideCode = outcode0 & outcode1 & outcode2;
1217
1218 // basic rejection criteria:
1219 if (sideCode == 0) {
1220 // ovelap clip:
1221 if (subdivide) {
1222 // avoid reentrance
1223 subdivide = false;
1224 // subdivide curve => call lineTo() with subdivided curves:
1225 boolean ret = curveSplitter.splitQuad(cx0, cy0, x1, y1,
1226 x2, y2, orCode, this);
1227 // reentrance is done:
1228 subdivide = true;
1229 if (ret) {
1230 return;
1231 }
1232 }
1233 // already subdivided so render it
1234 } else {
1235 this.cOutCode = outcode2;
1236 _moveTo(x2, y2, outcode0);
1237 opened = true;
1238 return;
1239 }
1240 }
1241
1242 this.cOutCode = outcode2;
1243 }
1244 _quadTo(x1, y1, x2, y2, outcode0);
1245 }
1246
1247 private void _quadTo(final double x1, final double y1,
1248 final double x2, final double y2,
1249 final int outcode0)
1250 {
1251 // need these so we can update the state at the end of this method
1252 double dxs = x1 - cx0;
1253 double dys = y1 - cy0;
1254 double dxf = x2 - x1;
1255 double dyf = y2 - y1;
1256
1257 if (((dxs == 0.0d) && (dys == 0.0d)) || ((dxf == 0.0d) && (dyf == 0.0d))) {
1258 dxs = dxf = x2 - cx0;
1259 dys = dyf = y2 - cy0;
1260 }
1261 if ((dxs == 0.0d) && (dys == 0.0d)) {
1262 // this happens if the "curve" is just a point
1263 // fix outcode0 for lineTo() call:
1264 if (clipRect != null) {
1265 this.cOutCode = outcode0;
1266 }
1267 lineTo(cx0, cy0);
1268 return;
1269 }
1270 // if these vectors are too small, normalize them, to avoid future
1271 // precision problems.
1272 if (Math.abs(dxs) < 0.1d && Math.abs(dys) < 0.1d) {
1273 final double len = Math.sqrt(dxs * dxs + dys * dys);
1274 dxs /= len;
1275 dys /= len;
1276 }
1277 if (Math.abs(dxf) < 0.1d && Math.abs(dyf) < 0.1d) {
1278 final double len = Math.sqrt(dxf * dxf + dyf * dyf);
1279 dxf /= len;
1280 dyf /= len;
1281 }
1282 computeOffset(dxs, dys, lineWidth2, offset0);
1283 drawJoin(cdx, cdy, cx0, cy0, dxs, dys, cmx, cmy, offset0[0], offset0[1], outcode0);
1284
1285 int nSplits = 0;
1286 final double[] mid;
1287 final double[] l = lp;
1288
1289 if (monotonize) {
1290 // monotonize quad:
1291 final CurveBasicMonotonizer monotonizer
1292 = rdrCtx.monotonizer.quad(cx0, cy0, x1, y1, x2, y2);
1293
1294 nSplits = monotonizer.nbSplits;
1295 mid = monotonizer.middle;
1296 } else {
1297 // use left instead:
1298 mid = l;
1299 mid[0] = cx0; mid[1] = cy0;
1300 mid[2] = x1; mid[3] = y1;
1301 mid[4] = x2; mid[5] = y2;
1302 }
1303 final double[] r = rp;
1304
1305 int kind = 0;
1306 for (int i = 0, off = 0; i <= nSplits; i++, off += 4) {
1307 kind = computeOffsetQuad(mid, off, l, r);
1308
1309 emitLineTo(l[0], l[1]);
1310
1311 switch(kind) {
1312 case 6:
1313 emitQuadTo(l[2], l[3], l[4], l[5]);
1314 emitQuadToRev(r[0], r[1], r[2], r[3]);
1315 break;
1316 case 4:
1317 emitLineTo(l[2], l[3]);
1318 emitLineToRev(r[0], r[1]);
1319 break;
1320 default:
1321 }
1322 emitLineToRev(r[kind - 2], r[kind - 1]);
1323 }
1324
1325 this.prev = DRAWING_OP_TO;
1326 this.cx0 = x2;
1327 this.cy0 = y2;
1328 this.cdx = dxf;
1329 this.cdy = dyf;
1330 this.cmx = (l[kind - 2] - r[kind - 2]) / 2.0d;
1331 this.cmy = (l[kind - 1] - r[kind - 1]) / 2.0d;
1332 }
1333
1334 @Override public long getNativeConsumer() {
1335 throw new InternalError("Stroker doesn't use a native consumer");
1336 }
1337 }
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