3 <html lang="en" xmlns="http://www.w3.org/1999/xhtml">
5 <meta charset="utf-8" />
10 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
11 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
15 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
16 {{{{306.58801299999999, -227.983994}, {212.46499600000001, -262.24200400000001}, {95.551200899999998, 58.976398500000002}}}, 0.707107008f} id=1
17 {{{{377.21899400000001, -141.98100299999999}, {237.77799285476553, -166.56830755921084}, {134.08399674208422, -155.06258330544892}}}, 0.788580656f} id=2
18 {{{{134.08399674208422, -155.06258330544892}, {30.390000629402859, -143.55685905168704}, {23.185499199999999, -102.697998}}}, 0.923879623f} id=4
22 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
23 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
24 {{{{205.78973252799028, -158.12538713371103}, {143.97848953841861, -74.076645245042371}, {95.551200899999998, 58.976398500000002}}}, 0.923879623f} id=3
25 {{{{377.21899400000001, -141.98100299999999}, {237.77799285476553, -166.56830755921084}, {134.08399674208422, -155.06258330544892}}}, 0.788580656f} id=2
29 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
30 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
31 {{{{205.78973252799028, -158.12538713371103}, {143.97848953841861, -74.076645245042371}, {95.551200899999998, 58.976398500000002}}}, 0.923879623f} id=3
32 {{{{252.08225670812539, -156.90491625851064}, {185.93099479842493, -160.81544543232982}, {134.08399674208422, -155.06258330544892}}}, 0.835816324f} id=6
36 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
37 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
38 {{{{205.78973252799028, -158.12538713371103}, {174.88411103320448, -116.10101618937664}, {145.19509369736275, -56.857102571363754}}}, 0.871667147f} id=3
39 {{{{252.08225670812539, -156.90491625851064}, {185.93099479842493, -160.81544543232982}, {134.08399674208422, -155.06258330544892}}}, 0.835816324f} id=6
43 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
44 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
45 {{{{205.78973252799028, -158.12538713371103}, {174.88411103320448, -116.10101618937664}, {145.19509369736275, -56.857102571363754}}}, 0.871667147f} id=3
46 {{{{252.08225670812539, -156.90491625851064}, {219.70109133058406, -158.81912754088933}, {190.17095392508796, -158.38373974664466}}}, 0.858306944f} id=6
50 {{{{306.588013,-227.983994}, {212.464996,-262.242004}, {95.5512009,58.9763985}}}, 0.707107008f},
51 {{{{377.218994,-141.981003}, {40.578701,-201.339996}, {23.1854992,-102.697998}}}, 0.707107008f},
52 {{{{205.78973252799028, -158.12538713371103}, {190.33692178059735, -137.11320166154385}, {174.87004877564593, -111.2132534799228}}}, 0.858117759f} id=3
53 {{{{252.08225670812539, -156.90491625851064}, {219.70109133058406, -158.81912754088933}, {190.17095392508796, -158.38373974664466}}}, 0.858306944f} id=6
58 <script type="text/javascript">
70 var decimal_places = 3;
78 var xmin, xmax, ymin, ymax;
82 var mouseDown = false;
84 var screenWidth, screenHeight;
94 var focus_on_selection = 0;
97 var draw_closest_t = false;
98 var draw_cubic_red = false;
99 var draw_derivative = false;
100 var draw_endpoints = 2;
102 var draw_midpoint = 0;
103 var draw_mouse_xy = false;
104 var draw_order = false;
105 var draw_point_xy = false;
106 var draw_ray_intersect = false;
107 var draw_quarterpoint = 0;
108 var draw_tangents = 1;
109 var draw_sortpoint = 0;
110 var retina_scale = !!window.devicePixelRatio;
112 function parse(test, title) {
113 var curveStrs = test.split("{{");
114 var pattern = /-?\d+\.*\d*e?-?\d*/g;
116 for (var c in curveStrs) {
117 var curveStr = curveStrs[c];
118 var idPart = curveStr.split("id=");
120 if (idPart.length == 2) {
121 id = parseInt(idPart[1]);
122 curveStr = idPart[0];
124 var points = curveStr.match(pattern);
126 for (var wd in points) {
127 var num = parseFloat(points[wd]);
128 if (isNaN(num)) continue;
131 if (pts.length > 2) {
139 if (curves.length >= 1) {
141 testTitles.push(title);
145 function init(test) {
146 var canvas = document.getElementById('canvas');
147 if (!canvas.getContext) return;
148 ctx = canvas.getContext('2d');
149 var resScale = retina_scale && window.devicePixelRatio ? window.devicePixelRatio : 1;
150 var unscaledWidth = window.innerWidth - 20;
151 var unscaledHeight = window.innerHeight - 20;
152 screenWidth = unscaledWidth;
153 screenHeight = unscaledHeight;
154 canvas.width = unscaledWidth * resScale;
155 canvas.height = unscaledHeight * resScale;
156 canvas.style.width = unscaledWidth + 'px';
157 canvas.style.height = unscaledHeight + 'px';
159 ctx.scale(resScale, resScale);
165 for (var curves in test) {
166 var curve = test[curves];
167 var last = curve.length - (curve.length % 2 == 1 ? 1 : 0);
168 for (var idx = 0; idx < last; idx += 2) {
169 xmin = Math.min(xmin, curve[idx]);
170 xmax = Math.max(xmax, curve[idx]);
171 ymin = Math.min(ymin, curve[idx + 1]);
172 ymax = Math.max(ymax, curve[idx + 1]);
175 xmin -= Math.min(1, Math.max(xmax - xmin, ymax - ymin));
176 var testW = xmax - xmin;
177 var testH = ymax - ymin;
179 while (testW * subscale < 0.1 && testH * subscale < 0.1) {
182 while (testW * subscale > 10 && testH * subscale > 10) {
185 setScale(xmin, xmax, ymin, ymax);
186 mouseX = (screenWidth / 2) / scale + srcLeft;
187 mouseY = (screenHeight / 2) / scale + srcTop;
191 function setScale(x0, x1, y0, y1) {
192 var srcWidth = x1 - x0;
193 var srcHeight = y1 - y0;
194 var usableWidth = screenWidth;
195 var xDigits = Math.ceil(Math.log(Math.abs(xmax)) / Math.log(10));
196 var yDigits = Math.ceil(Math.log(Math.abs(ymax)) / Math.log(10));
197 usableWidth -= (xDigits + yDigits) * 10;
198 usableWidth -= decimal_places * 10;
199 var hscale = usableWidth / srcWidth;
200 var vscale = screenHeight / srcHeight;
201 scale = Math.min(hscale, vscale);
202 var invScale = 1 / scale;
203 var sxmin = x0 - invScale * 5;
204 var symin = y0 - invScale * 10;
205 var sxmax = x1 + invScale * (6 * decimal_places + 10);
206 var symax = y1 + invScale * 10;
207 srcWidth = sxmax - sxmin;
208 srcHeight = symax - symin;
209 hscale = usableWidth / srcWidth;
210 vscale = screenHeight / srcHeight;
211 scale = Math.min(hscale, vscale);
216 function dxy_at_t(curve, t) {
218 if (curve.length == 6) {
222 dxy.x = a * curve[0] + b * curve[2] + c * curve[4];
223 dxy.y = a * curve[1] + b * curve[3] + c * curve[5];
224 } else if (curve.length == 7) {
225 var p20x = curve[4] - curve[0];
226 var p20y = curve[5] - curve[1];
227 var p10xw = (curve[2] - curve[0]) * curve[6];
228 var p10yw = (curve[3] - curve[1]) * curve[6];
229 var coeff0x = curve[6] * p20x - p20x;
230 var coeff0y = curve[6] * p20y - p20y;
231 var coeff1x = p20x - 2 * p10xw;
232 var coeff1y = p20y - 2 * p10yw;
233 dxy.x = t * (t * coeff0x + coeff1x) + p10xw;
234 dxy.y = t * (t * coeff0y + coeff1y) + p10yw;
235 } else if (curve.length == 8) {
241 dxy.x = 3 * ((b - a) * one_t * one_t + 2 * (c - b) * t * one_t + (d - c) * t * t);
246 dxy.y = 3 * ((b - a) * one_t * one_t + 2 * (c - b) * t * one_t + (d - c) * t * t);
251 var flt_epsilon = 1.19209290E-07;
253 function approximately_zero(A) {
254 return Math.abs(A) < flt_epsilon;
257 function approximately_zero_inverse(A) {
258 return Math.abs(A) > (1 / flt_epsilon);
261 function quad_real_roots(A, B, C) {
265 if (approximately_zero(A) && (approximately_zero_inverse(p)
266 || approximately_zero_inverse(q))) {
267 if (approximately_zero(B)) {
276 /* normal form: x^2 + px + q = 0 */
278 if (!approximately_zero(p2 - q) && p2 < q) {
283 sqrt_D = Math.sqrt(p2 - q);
286 var flip = -sqrt_D - p;
287 if (!approximately_zero(s[0] - flip)) {
293 function cubic_real_roots(A, B, C, D) {
294 if (approximately_zero(A)) { // we're just a quadratic
295 return quad_real_roots(B, C, D);
297 if (approximately_zero(D)) { // 0 is one root
298 var s = quad_real_roots(A, B, C);
299 for (var i = 0; i < s.length; ++i) {
300 if (approximately_zero(s[i])) {
307 if (approximately_zero(A + B + C + D)) { // 1 is one root
308 var s = quad_real_roots(A, A + B, -D);
309 for (var i = 0; i < s.length; ++i) {
310 if (approximately_zero(s[i] - 1)) {
323 var Q = (a2 - b * 3) / 9;
324 var R = (2 * a2 * a - 9 * a * b + 27 * c) / 54;
327 var R2MinusQ3 = R2 - Q3;
331 if (R2MinusQ3 < 0) { // we have 3 real roots
332 var theta = Math.acos(R / Math.sqrt(Q3));
333 var neg2RootQ = -2 * Math.sqrt(Q);
334 r = neg2RootQ * Math.cos(theta / 3) - adiv3;
336 r = neg2RootQ * Math.cos((theta + 2 * Math.PI) / 3) - adiv3;
337 if (!approximately_zero(roots[0] - r)) {
340 r = neg2RootQ * Math.cos((theta - 2 * Math.PI) / 3) - adiv3;
341 if (!approximately_zero(roots[0] - r) && (roots.length == 1
342 || !approximately_zero(roots[1] - r))) {
345 } else { // we have 1 real root
346 var sqrtR2MinusQ3 = Math.sqrt(R2MinusQ3);
347 var A = Math.abs(R) + sqrtR2MinusQ3;
348 A = Math.pow(A, 1/3);
357 if (approximately_zero(R2 - Q3)) {
359 if (!approximately_zero(roots[0] - r)) {
367 function approximately_zero_or_more(tValue) {
368 return tValue >= -flt_epsilon;
371 function approximately_one_or_less(tValue) {
372 return tValue <= 1 + flt_epsilon;
375 function approximately_less_than_zero(tValue) {
376 return tValue < flt_epsilon;
379 function approximately_greater_than_one(tValue) {
380 return tValue > 1 - flt_epsilon;
383 function add_valid_ts(s) {
386 for (var index = 0; index < s.length; ++index) {
387 var tValue = s[index];
388 if (approximately_zero_or_more(tValue) && approximately_one_or_less(tValue)) {
389 if (approximately_less_than_zero(tValue)) {
391 } else if (approximately_greater_than_one(tValue)) {
394 for (var idx2 = 0; idx2 < t.length; ++idx2) {
395 if (approximately_zero(t[idx2] - tValue)) {
405 function quad_roots(A, B, C) {
406 var s = quad_real_roots(A, B, C);
407 var foundRoots = add_valid_ts(s);
411 function cubic_roots(A, B, C, D) {
412 var s = cubic_real_roots(A, B, C, D);
413 var foundRoots = add_valid_ts(s);
417 function ray_curve_intersect(startPt, endPt, curve) {
418 var adj = endPt[0] - startPt[0];
419 var opp = endPt[1] - startPt[1];
421 var len = (curve.length == 7 ? 6 : curve.length) / 2;
422 for (var n = 0; n < len; ++n) {
423 r[n] = (curve[n * 2 + 1] - startPt[1]) * adj - (curve[n * 2] - startPt[0]) * opp;
425 if (curve.length == 6) {
429 A += C - 2 * B; // A = a - 2*b + c
430 B -= C; // B = -(b - c)
431 return quad_roots(A, 2 * B, C);
433 if (curve.length == 7) {
435 var B = r[1] * curve[6];
437 A += C - 2 * B; // A = a - 2*b + c
438 B -= C; // B = -(b - c)
439 return quad_roots(A, 2 * B, C);
442 var B = r[2] * 3; // 3*c
443 var C = r[1] * 3; // 3*b
445 A -= D - C + B; // A = -a + 3*b - 3*c + d
446 B += 3 * D - 2 * C; // B = 3*a - 6*b + 3*c
447 C -= 3 * D; // C = -3*a + 3*b
448 return cubic_roots(A, B, C, D);
451 function x_at_t(curve, t) {
453 if (curve.length == 4) {
454 return one_t * curve[0] + t * curve[2];
456 var one_t2 = one_t * one_t;
458 if (curve.length == 6) {
459 return one_t2 * curve[0] + 2 * one_t * t * curve[2] + t2 * curve[4];
461 if (curve.length == 7) {
462 var numer = one_t2 * curve[0] + 2 * one_t * t * curve[2] * curve[6]
464 var denom = one_t2 + 2 * one_t * t * curve[6]
466 return numer / denom;
468 var a = one_t2 * one_t;
469 var b = 3 * one_t2 * t;
470 var c = 3 * one_t * t2;
472 return a * curve[0] + b * curve[2] + c * curve[4] + d * curve[6];
475 function y_at_t(curve, t) {
477 if (curve.length == 4) {
478 return one_t * curve[1] + t * curve[3];
480 var one_t2 = one_t * one_t;
482 if (curve.length == 6) {
483 return one_t2 * curve[1] + 2 * one_t * t * curve[3] + t2 * curve[5];
485 if (curve.length == 7) {
486 var numer = one_t2 * curve[1] + 2 * one_t * t * curve[3] * curve[6]
488 var denom = one_t2 + 2 * one_t * t * curve[6]
490 return numer / denom;
492 var a = one_t2 * one_t;
493 var b = 3 * one_t2 * t;
494 var c = 3 * one_t * t2;
496 return a * curve[1] + b * curve[3] + c * curve[5] + d * curve[7];
499 function drawPointAtT(curve) {
500 var x = x_at_t(curve, curveT);
501 var y = y_at_t(curve, curveT);
505 function drawLine(x1, y1, x2, y2) {
507 ctx.moveTo((x1 - srcLeft) * scale,
508 (y1 - srcTop) * scale);
509 ctx.lineTo((x2 - srcLeft) * scale,
510 (y2 - srcTop) * scale);
514 function drawPoint(px, py) {
515 for (var pts = 0; pts < drawnPts.length; pts += 2) {
516 var x = drawnPts[pts];
517 var y = drawnPts[pts + 1];
518 if (px == x && py == y) {
524 var _px = (px - srcLeft) * scale;
525 var _py = (py - srcTop) * scale;
527 ctx.arc(_px, _py, 3, 0, Math.PI * 2, true);
531 var label = px.toFixed(decimal_places) + ", " + py.toFixed(decimal_places);
532 ctx.font = "normal 10px Arial";
533 ctx.textAlign = "left";
534 ctx.fillStyle = "black";
535 ctx.fillText(label, _px + 5, _py);
539 function drawPointSolid(px, py) {
541 ctx.fillStyle = "rgba(0,0,0, 0.4)";
545 function crossPt(origin, pt1, pt2) {
546 return ((pt1[0] - origin[0]) * (pt2[1] - origin[1])
547 - (pt1[1] - origin[1]) * (pt2[0] - origin[0])) > 0 ? 0 : 1;
550 // may not work well for cubics
551 function curveClosestT(curve, x, y) {
553 var closestDist = Infinity;
554 var l = Infinity, t = Infinity, r = -Infinity, b = -Infinity;
555 for (var i = 0; i < 16; ++i) {
556 var testX = x_at_t(curve, i / 16);
557 l = Math.min(testX, l);
558 r = Math.max(testX, r);
559 var testY = y_at_t(curve, i / 16);
560 t = Math.min(testY, t);
561 b = Math.max(testY, b);
564 var dist = dx * dx + dy * dy;
565 if (closestDist > dist) {
572 var boundsDist = boundsX * boundsX + boundsY * boundsY;
573 if (closestDist > boundsDist) {
576 console.log("closestDist = " + closestDist + " boundsDist = " + boundsDist
577 + " t = " + closest / 16);
581 var kMaxConicToQuadPOW2 = 5;
583 function computeQuadPOW2(curve, tol) {
584 var a = curve[6] - 1;
585 var k = a / (4 * (2 + a));
586 var x = k * (curve[0] - 2 * curve[2] + curve[4]);
587 var y = k * (curve[1] - 2 * curve[3] + curve[5]);
589 var error = Math.sqrt(x * x + y * y);
591 for (pow2 = 0; pow2 < kMaxConicToQuadPOW2; ++pow2) {
600 function subdivide_w_value(w) {
601 return Math.sqrt(0.5 + w * 0.5);
604 function chop(curve, part1, part2) {
606 var scale = 1 / (1 + w);
609 part1[2] = (curve[0] + curve[2] * w) * scale;
610 part1[3] = (curve[1] + curve[3] * w) * scale;
611 part1[4] = part2[0] = (curve[0] + (curve[2] * w) * 2 + curve[4]) * scale * 0.5;
612 part1[5] = part2[1] = (curve[1] + (curve[3] * w) * 2 + curve[5]) * scale * 0.5;
613 part2[2] = (curve[2] * w + curve[4]) * scale;
614 part2[3] = (curve[3] * w + curve[5]) * scale;
617 part1[6] = part2[6] = subdivide_w_value(w);
620 function subdivide(curve, level, pts) {
627 var part1 = [], part2 = [];
628 chop(curve, part1, part2);
630 subdivide(part1, level, pts);
631 subdivide(part2, level, pts);
635 function chopIntoQuadsPOW2(curve, pow2, pts) {
636 subdivide(curve, pow2, pts);
640 function drawConic(curve, srcLeft, srcTop, scale) {
642 var pow2 = computeQuadPOW2(curve, tol);
644 chopIntoQuadsPOW2(curve, pow2, pts);
645 for (var i = 0; i < pts.length; i += 4) {
646 ctx.quadraticCurveTo(
647 (pts[i + 0] - srcLeft) * scale, (pts[i + 1] - srcTop) * scale,
648 (pts[i + 2] - srcLeft) * scale, (pts[i + 3] - srcTop) * scale);
652 function draw(test, title) {
653 ctx.font = "normal 50px Arial";
654 ctx.textAlign = "left";
655 ctx.fillStyle = "rgba(0,0,0, 0.1)";
656 ctx.fillText(title, 50, 50);
657 ctx.font = "normal 10px Arial";
658 // ctx.lineWidth = "1.001"; "0.999";
664 var shortSpokes = [];
668 for (var curves in test) {
669 var curve = test[curves];
670 origin.push(curve[0]);
671 origin.push(curve[1]);
673 startPt.push(curve[2]);
674 startPt.push(curve[3]);
675 hullStarts.push(startPt);
677 if (curve.length == 4) {
678 endPt.push(curve[2]);
679 endPt.push(curve[3]);
680 } else if (curve.length == 6 || curve.length == 7) {
681 endPt.push(curve[4]);
682 endPt.push(curve[5]);
683 } else if (curve.length == 8) {
684 endPt.push(curve[6]);
685 endPt.push(curve[7]);
687 hullEnds.push(endPt);
688 var sweep = crossPt(origin, startPt, endPt);
691 midPt.push(x_at_t(curve, 0.5));
692 midPt.push(y_at_t(curve, 0.5));
693 midSpokes.push(midPt);
695 shortPt.push(x_at_t(curve, 0.25));
696 shortPt.push(y_at_t(curve, 0.25));
697 shortSpokes.push(shortPt);
698 var dx = midPt[0] - origin[0];
699 var dy = midPt[1] - origin[1];
700 var dist = Math.sqrt(dx * dx + dy * dy);
702 dx = shortPt[0] - origin[0];
703 dy = shortPt[1] - origin[1];
704 dist = Math.sqrt(dx * dx + dy * dy);
705 shortDist.push(dist);
708 var useIntersect = false;
709 var maxWidth = Math.max(xmax - xmin, ymax - ymin);
710 for (var curves in test) {
711 var curve = test[curves];
712 if (curve.length >= 6 && curve.length <= 8) {
713 var opp = curves == 0 || curves == 1 ? 0 : 1;
714 var sects = ray_curve_intersect(origin, hullEnds[opp], curve);
715 intersect.push(sects);
716 if (sects.length > 1) {
717 var intersection = sects[0];
718 if (intersection == 0) {
719 intersection = sects[1];
721 var ix = x_at_t(curve, intersection) - origin[0];
722 var iy = y_at_t(curve, intersection) - origin[1];
723 var ex = hullEnds[opp][0] - origin[0];
724 var ey = hullEnds[opp][1] - origin[1];
725 if (ix * ex >= 0 && iy * ey >= 0) {
726 var iDist = Math.sqrt(ix * ix + iy * iy);
727 var eDist = Math.sqrt(ex * ex + ey * ey);
728 var delta = Math.abs(iDist - eDist) / maxWidth;
729 if (delta > (curve.length != 8 ? 1e-5 : 1e-4)) {
730 useIntersect ^= true;
736 var midLeft = curves != 0 ? crossPt(origin, midSpokes[0], midSpokes[1]) : 0;
739 var sect1 = intersect[0].length > 1;
740 var sIndex = sect1 ? 0 : 1;
741 var sects = intersect[sIndex];
742 var intersection = sects[0];
743 if (intersection == 0) {
744 intersection = sects[1];
746 var curve = test[sIndex];
747 var ix = x_at_t(curve, intersection) - origin[0];
748 var iy = y_at_t(curve, intersection) - origin[1];
749 var opp = sect1 ? 1 : 0;
750 var ex = hullEnds[opp][0] - origin[0];
751 var ey = hullEnds[opp][1] - origin[1];
752 var iDist = ix * ix + iy * iy;
753 var eDist = ex * ex + ey * ey;
754 firstInside = (iDist > eDist) ^ (sIndex == 0) ^ sweeps[0];
755 // console.log("iDist=" + iDist + " eDist=" + eDist + " sIndex=" + sIndex
756 // + " sweeps[0]=" + sweeps[0]);
758 // console.log("midLeft=" + midLeft);
759 firstInside = midLeft != 0;
761 var shorter = midDist[1] < midDist[0];
762 var shortLeft = shorter ? crossPt(origin, shortSpokes[0], midSpokes[1])
763 : crossPt(origin, midSpokes[0], shortSpokes[1]);
764 var startCross = crossPt(origin, hullStarts[0], hullStarts[1]);
765 var disallowShort = midLeft == startCross && midLeft == sweeps[0]
766 && midLeft == sweeps[1];
768 // console.log("midLeft=" + midLeft + " startCross=" + startCross);
769 var intersectIndex = 0;
770 for (var curves in test) {
771 var curve = test[draw_id != 2 ? curves : test.length - curves - 1];
772 if (curve.length != 4 && curve.length != 6 && curve.length != 7 && curve.length != 8) {
776 if (draw_tangents != 0) {
777 if (draw_cubic_red ? curve.length == 8 : firstInside == curves) {
778 ctx.strokeStyle = "rgba(255,0,0, 0.3)";
780 ctx.strokeStyle = "rgba(0,0,255, 0.3)";
782 drawLine(curve[0], curve[1], curve[2], curve[3]);
783 if (draw_tangents != 2) {
784 if (curve.length > 4) drawLine(curve[2], curve[3], curve[4], curve[5]);
785 if (curve.length == 8) drawLine(curve[4], curve[5], curve[6], curve[7]);
787 if (draw_tangents != 1) {
788 if (curve.length == 6 || curve.length == 7) {
789 drawLine(curve[0], curve[1], curve[4], curve[5]);
791 if (curve.length == 8) drawLine(curve[0], curve[1], curve[6], curve[7]);
795 ctx.moveTo((curve[0] - srcLeft) * scale, (curve[1] - srcTop) * scale);
796 if (curve.length == 4) {
797 ctx.lineTo((curve[2] - srcLeft) * scale, (curve[3] - srcTop) * scale);
798 } else if (curve.length == 6) {
799 ctx.quadraticCurveTo(
800 (curve[2] - srcLeft) * scale, (curve[3] - srcTop) * scale,
801 (curve[4] - srcLeft) * scale, (curve[5] - srcTop) * scale);
802 } else if (curve.length == 7) {
803 drawConic(curve, srcLeft, srcTop, scale);
806 (curve[2] - srcLeft) * scale, (curve[3] - srcTop) * scale,
807 (curve[4] - srcLeft) * scale, (curve[5] - srcTop) * scale,
808 (curve[6] - srcLeft) * scale, (curve[7] - srcTop) * scale);
810 if (draw_cubic_red ? curve.length == 8 : firstInside == curves) {
811 ctx.strokeStyle = "rgba(255,0,0, 1)";
813 ctx.strokeStyle = "rgba(0,0,255, 1)";
816 if (draw_endpoints > 0) {
817 drawPoint(curve[0], curve[1]);
818 if (draw_endpoints > 1 || curve.length == 4) {
819 drawPoint(curve[2], curve[3]);
821 if (curve.length == 6 || curve.length == 7 ||
822 (draw_endpoints > 1 && curve.length == 8)) {
823 drawPoint(curve[4], curve[5]);
825 if (curve.length == 8) drawPoint(curve[6], curve[7]);
827 if (draw_midpoint != 0) {
828 if ((curves == 0) == (midLeft == 0)) {
829 ctx.strokeStyle = "rgba(0,180,127, 0.6)";
831 ctx.strokeStyle = "rgba(127,0,127, 0.6)";
833 var midX = x_at_t(curve, 0.5);
834 var midY = y_at_t(curve, 0.5);
835 drawPointSolid(midX, midY);
836 if (draw_midpoint > 1) {
837 drawLine(curve[0], curve[1], midX, midY);
840 if (draw_quarterpoint != 0) {
841 if ((curves == 0) == (shortLeft == 0)) {
842 ctx.strokeStyle = "rgba(0,191,63, 0.6)";
844 ctx.strokeStyle = "rgba(63,0,191, 0.6)";
846 var midT = (curves == 0) == shorter ? 0.25 : 0.5;
847 var midX = x_at_t(curve, midT);
848 var midY = y_at_t(curve, midT);
849 drawPointSolid(midX, midY);
850 if (draw_quarterpoint > 1) {
851 drawLine(curve[0], curve[1], midX, midY);
854 if (draw_sortpoint != 0) {
855 if ((curves == 0) == ((disallowShort == -1 ? midLeft : shortLeft) == 0)) {
856 ctx.strokeStyle = "rgba(0,155,37, 0.6)";
858 ctx.strokeStyle = "rgba(37,0,155, 0.6)";
860 var midT = (curves == 0) == shorter && disallowShort != curves ? 0.25 : 0.5;
861 console.log("curves=" + curves + " disallowShort=" + disallowShort
862 + " midLeft=" + midLeft + " shortLeft=" + shortLeft
863 + " shorter=" + shorter + " midT=" + midT);
864 var midX = x_at_t(curve, midT);
865 var midY = y_at_t(curve, midT);
866 drawPointSolid(midX, midY);
867 if (draw_sortpoint > 1) {
868 drawLine(curve[0], curve[1], midX, midY);
871 if (draw_ray_intersect != 0) {
872 ctx.strokeStyle = "rgba(75,45,199, 0.6)";
873 if (curve.length >= 6 && curve.length <= 8) {
874 var intersections = intersect[intersectIndex];
875 for (var i in intersections) {
876 var intersection = intersections[i];
877 var x = x_at_t(curve, intersection);
878 var y = y_at_t(curve, intersection);
879 drawPointSolid(x, y);
880 if (draw_ray_intersect > 1) {
881 drawLine(curve[0], curve[1], x, y);
888 var px = x_at_t(curve, 0.75);
889 var py = y_at_t(curve, 0.75);
890 var _px = (px - srcLeft) * scale;
891 var _py = (py - srcTop) * scale;
893 ctx.arc(_px, _py, 15, 0, Math.PI * 2, true);
895 ctx.fillStyle = "white";
897 if (draw_cubic_red ? curve.length == 8 : firstInside == curves) {
898 ctx.strokeStyle = "rgba(255,0,0, 1)";
899 ctx.fillStyle = "rgba(255,0,0, 1)";
901 ctx.strokeStyle = "rgba(0,0,255, 1)";
902 ctx.fillStyle = "rgba(0,0,255, 1)";
905 ctx.font = "normal 16px Arial";
906 ctx.textAlign = "center";
907 ctx.fillText(parseInt(curves) + 1, _px, _py + 5);
909 if (draw_closest_t) {
910 var t = curveClosestT(curve, mouseX, mouseY);
912 var x = x_at_t(curve, t);
913 var y = y_at_t(curve, t);
914 drawPointSolid(x, y);
917 if (!approximately_zero(scale - initScale)) {
918 ctx.font = "normal 20px Arial";
919 ctx.fillStyle = "rgba(0,0,0, 0.3)";
920 ctx.textAlign = "right";
921 ctx.fillText(scale.toFixed(decimal_places) + 'x',
922 screenWidth - 10, screenHeight - 5);
929 for (var i = 0; i < ids.length; i += 2) {
930 if (ids[i + 1] == curve) {
936 var px = x_at_t(curve, 0.5);
937 var py = y_at_t(curve, 0.5);
938 var _px = (px - srcLeft) * scale;
939 var _py = (py - srcTop) * scale;
941 ctx.arc(_px, _py, 15, 0, Math.PI * 2, true);
943 ctx.fillStyle = "white";
945 ctx.strokeStyle = "rgba(255,0,0, 1)";
946 ctx.fillStyle = "rgba(255,0,0, 1)";
948 ctx.font = "normal 16px Arial";
949 ctx.textAlign = "center";
950 ctx.fillText(id, _px, _py + 5);
962 function drawCurveTControl() {
964 ctx.strokeStyle = "rgba(0,0,0, 0.3)";
966 ctx.rect(screenWidth - 80, 40, 28, screenHeight - 80);
968 var ty = 40 + curveT * (screenHeight - 80);
970 ctx.moveTo(screenWidth - 80, ty);
971 ctx.lineTo(screenWidth - 85, ty - 5);
972 ctx.lineTo(screenWidth - 85, ty + 5);
973 ctx.lineTo(screenWidth - 80, ty);
974 ctx.fillStyle = "rgba(0,0,0, 0.6)";
976 var num = curveT.toFixed(decimal_places);
977 ctx.font = "normal 10px Arial";
978 ctx.textAlign = "left";
979 ctx.fillText(num, screenWidth - 78, ty);
982 function drawCurveWControl() {
985 for (var curves in tests[testIndex]) {
986 var curve = tests[testIndex][curves];
987 if (curve.length != 7) {
990 if (choice == curveW) {
1000 ctx.strokeStyle = "rgba(0,0,0, 0.3)";
1002 ctx.rect(screenWidth - 40, 40, 28, screenHeight - 80);
1004 var ty = 40 + w * (screenHeight - 80);
1006 ctx.moveTo(screenWidth - 40, ty);
1007 ctx.lineTo(screenWidth - 45, ty - 5);
1008 ctx.lineTo(screenWidth - 45, ty + 5);
1009 ctx.lineTo(screenWidth - 40, ty);
1010 ctx.fillStyle = "rgba(0,0,0, 0.6)";
1012 var num = w.toFixed(decimal_places);
1013 ctx.font = "normal 10px Arial";
1014 ctx.textAlign = "left";
1015 ctx.fillText(num, screenWidth - 38, ty);
1018 function ptInTControl() {
1019 var e = window.event;
1020 var tgt = e.target || e.srcElement;
1021 var left = tgt.offsetLeft;
1022 var top = tgt.offsetTop;
1023 var x = (e.clientX - left);
1024 var y = (e.clientY - top);
1025 if (x < screenWidth - 80 || x > screenWidth - 50) {
1028 if (y < 40 || y > screenHeight - 80) {
1031 curveT = (y - 40) / (screenHeight - 120);
1032 if (curveT < 0 || curveT > 1) {
1033 throw "stop execution";
1038 function ptInWControl() {
1039 var e = window.event;
1040 var tgt = e.target || e.srcElement;
1041 var left = tgt.offsetLeft;
1042 var top = tgt.offsetTop;
1043 var x = (e.clientX - left);
1044 var y = (e.clientY - top);
1045 if (x < screenWidth - 40 || x > screenWidth - 10) {
1048 if (y < 40 || y > screenHeight - 80) {
1051 var w = (y - 40) / (screenHeight - 120);
1052 if (w < 0 || w > 1) {
1053 throw "stop execution";
1056 for (var curves in tests[testIndex]) {
1057 var curve = tests[testIndex][curves];
1058 if (curve.length != 7) {
1061 if (choice == curveW) {
1070 function drawTop() {
1071 init(tests[testIndex]);
1076 if (focus_on_selection > 0) {
1077 var focusXmin = focusYmin = Infinity;
1078 var focusXmax = focusYmax = -Infinity;
1080 for (var curves in tests[testIndex]) {
1081 if (++choice != focus_on_selection) {
1084 var curve = tests[testIndex][curves];
1085 var last = curve.length - (curve.length % 2 == 1 ? 1 : 0);
1086 for (var idx = 0; idx < last; idx += 2) {
1087 focusXmin = Math.min(focusXmin, curve[idx]);
1088 focusXmax = Math.max(focusXmax, curve[idx]);
1089 focusYmin = Math.min(focusYmin, curve[idx + 1]);
1090 focusYmax = Math.max(focusYmax, curve[idx + 1]);
1093 focusXmin -= Math.min(1, Math.max(focusXmax - focusXmin, focusYmax - focusYmin));
1094 if (focusXmin < focusXmax && focusYmin < focusYmax) {
1095 setScale(focusXmin, focusXmax, focusYmin, focusYmax);
1099 ctx.rect(0, 0, ctx.canvas.width, ctx.canvas.height);
1100 ctx.fillStyle = "white";
1102 draw(tests[testIndex], testTitles[testIndex]);
1105 function doKeyPress(evt) {
1106 var char = String.fromCharCode(evt.charCode);
1107 var focusWasOn = false;
1119 decimal_places = char - '0';
1123 focusWasOn = focus_on_selection;
1125 focus_on_selection = false;
1132 focus_on_selection = focusWasOn;
1136 focusWasOn = focus_on_selection;
1138 focus_on_selection = false;
1145 focus_on_selection = focusWasOn;
1148 draw_cubic_red ^= true;
1155 var test = tests[testIndex];
1157 for (var curves in test) {
1158 var c = test[curves];
1160 for (var index = 0; index < c.length; ++index) {
1161 cClone.push(c[index]);
1163 testClone.push(cClone);
1165 tests.push(testClone);
1166 testTitles.push(testTitles[testIndex] + " copy");
1167 testIndex = tests.length - 1;
1171 draw_endpoints = (draw_endpoints + 1) % 3;
1175 draw_derivative ^= true;
1179 draw_ray_intersect = (draw_ray_intersect + 1) % 3;
1183 var test = tests[testIndex];
1184 console.log("<div id=\"" + testTitles[testIndex] + "\" >");
1185 for (var curves in test) {
1186 var c = test[curves];
1188 for (var i = 0; i < c.length; i += 2) {
1190 s += c[i] + "," + c[i + 1];
1192 if (i + 2 < c.length) {
1196 console.log(s + "}},");
1198 console.log("</div>");
1201 draw_midpoint = (draw_midpoint + 1) % 3;
1207 testIndex = (testIndex + 1) % tests.length;
1217 if (--testIndex < 0)
1218 testIndex = tests.length - 1;
1222 draw_quarterpoint = (draw_quarterpoint + 1) % 3;
1226 for (var i = 0; i < testDivs.length; ++i) {
1227 var title = testDivs[i].id.toString();
1228 if (title == testTitles[testIndex]) {
1229 var str = testDivs[i].firstChild.data;
1231 var original = tests.pop();
1233 tests[testIndex] = original;
1240 draw_sortpoint = (draw_sortpoint + 1) % 3;
1248 draw_closest_t ^= true;
1252 draw_tangents = (draw_tangents + 1) % 4;
1259 for (var curves in tests[testIndex]) {
1260 var curve = tests[testIndex][curves];
1261 if (curve.length != 7) {
1264 if (choice == curveW) {
1276 draw_point_xy ^= true;
1280 draw_mouse_xy ^= true;
1284 retina_scale ^= true;
1288 ++focus_on_selection;
1289 if (focus_on_selection >= tests[testIndex].length) {
1290 focus_on_selection = 0;
1292 setScale(xmin, xmax, ymin, ymax);
1296 draw_id = (draw_id + 1) % 3;
1302 function doKeyDown(evt) {
1303 var char = evt.keyCode;
1304 var preventDefault = false;
1306 case 37: // left arrow
1310 if (--testIndex < 0)
1311 testIndex = tests.length - 1;
1317 preventDefault = true;
1319 case 39: // right arrow
1323 if (++testIndex >= tests.length)
1330 preventDefault = true;
1333 if (preventDefault) {
1334 evt.preventDefault();
1341 var e = window.event;
1342 var tgt = e.target || e.srcElement;
1343 var left = tgt.offsetLeft;
1344 var top = tgt.offsetTop;
1345 mouseX = (e.clientX - left) / scale + srcLeft;
1346 mouseY = (e.clientY - top) / scale + srcTop;
1349 function calcLeftTop() {
1350 srcLeft = mouseX - screenWidth / 2 / scale;
1351 srcTop = mouseY - screenHeight / 2 / scale;
1354 function handleMouseClick() {
1355 if ((!draw_t || !ptInTControl()) && (!draw_w || !ptInWControl())) {
1362 function initDown() {
1363 var test = tests[testIndex];
1364 var bestDistance = 1000000;
1366 for (var curves in test) {
1367 var testCurve = test[curves];
1368 if (testCurve.length != 4 && (testCurve.length < 6 || testCurve.length > 8)) {
1371 var testMax = testCurve.length == 7 ? 6 : testCurve.length;
1372 for (var i = 0; i < testMax; i += 2) {
1373 var testX = testCurve[i];
1374 var testY = testCurve[i + 1];
1375 var dx = testX - mouseX;
1376 var dy = testY - mouseY;
1377 var dist = dx * dx + dy * dy;
1378 if (dist > bestDistance) {
1381 activeCurve = testCurve;
1383 bestDistance = dist;
1386 if (activePt >= 0) {
1392 function handleMouseOver() {
1394 if (draw_mouse_xy) {
1395 var num = mouseX.toFixed(decimal_places) + ", " + mouseY.toFixed(decimal_places);
1397 ctx.rect(300, 100, num.length * 6, 10);
1398 ctx.fillStyle = "white";
1400 ctx.font = "normal 10px Arial";
1401 ctx.fillStyle = "black";
1402 ctx.textAlign = "left";
1403 ctx.fillText(num, 300, 108);
1413 var deltaX = mouseX - lastX;
1414 var deltaY = mouseY - lastY;
1417 if (activePt == 0) {
1418 var test = tests[testIndex];
1419 for (var curves in test) {
1420 var testCurve = test[curves];
1421 testCurve[0] += deltaX;
1422 testCurve[1] += deltaY;
1425 activeCurve[activePt] += deltaX;
1426 activeCurve[activePt + 1] += deltaY;
1432 for (var i = 0; i < testDivs.length; ++i) {
1433 var title = testDivs[i].id.toString();
1434 var str = testDivs[i].firstChild.data;
1438 window.addEventListener('keypress', doKeyPress, true);
1439 window.addEventListener('keydown', doKeyDown, true);
1440 window.onresize = function () {
1448 <body onLoad="start();">
1450 <canvas id="canvas" width="750" height="500"
1451 onmousedown="mouseDown = true"
1452 onmouseup="mouseDown = false"
1453 onmousemove="handleMouseOver()"
1454 onclick="handleMouseClick()"