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- "use strict";
- Object.defineProperty(exports, "__esModule", { value: true });
- exports.arcToCubic = void 0;
- var TAU = Math.PI * 2;
- var mapToEllipse = function (_a, rx, ry, cosphi, sinphi, centerx, centery) {
- var x = _a.x, y = _a.y;
- x *= rx;
- y *= ry;
- var xp = cosphi * x - sinphi * y;
- var yp = sinphi * x + cosphi * y;
- return {
- x: xp + centerx,
- y: yp + centery
- };
- };
- var approxUnitArc = function (ang1, ang2) {
- // If 90 degree circular arc, use a constant
- // as derived from http://spencermortensen.com/articles/bezier-circle
- var a = ang2 === 1.5707963267948966
- ? 0.551915024494
- : ang2 === -1.5707963267948966
- ? -0.551915024494
- : 4 / 3 * Math.tan(ang2 / 4);
- var x1 = Math.cos(ang1);
- var y1 = Math.sin(ang1);
- var x2 = Math.cos(ang1 + ang2);
- var y2 = Math.sin(ang1 + ang2);
- return [
- {
- x: x1 - y1 * a,
- y: y1 + x1 * a
- },
- {
- x: x2 + y2 * a,
- y: y2 - x2 * a
- },
- {
- x: x2,
- y: y2
- }
- ];
- };
- var vectorAngle = function (ux, uy, vx, vy) {
- var sign = (ux * vy - uy * vx < 0) ? -1 : 1;
- var dot = ux * vx + uy * vy;
- if (dot > 1) {
- dot = 1;
- }
- if (dot < -1) {
- dot = -1;
- }
- return sign * Math.acos(dot);
- };
- var getArcCenter = function (px, py, cx, cy, rx, ry, largeArcFlag, sweepFlag, sinphi, cosphi, pxp, pyp) {
- var rxsq = Math.pow(rx, 2);
- var rysq = Math.pow(ry, 2);
- var pxpsq = Math.pow(pxp, 2);
- var pypsq = Math.pow(pyp, 2);
- var radicant = (rxsq * rysq) - (rxsq * pypsq) - (rysq * pxpsq);
- if (radicant < 0) {
- radicant = 0;
- }
- radicant /= (rxsq * pypsq) + (rysq * pxpsq);
- radicant = Math.sqrt(radicant) * (largeArcFlag === sweepFlag ? -1 : 1);
- var centerxp = radicant * rx / ry * pyp;
- var centeryp = radicant * -ry / rx * pxp;
- var centerx = cosphi * centerxp - sinphi * centeryp + (px + cx) / 2;
- var centery = sinphi * centerxp + cosphi * centeryp + (py + cy) / 2;
- var vx1 = (pxp - centerxp) / rx;
- var vy1 = (pyp - centeryp) / ry;
- var vx2 = (-pxp - centerxp) / rx;
- var vy2 = (-pyp - centeryp) / ry;
- var ang1 = vectorAngle(1, 0, vx1, vy1);
- var ang2 = vectorAngle(vx1, vy1, vx2, vy2);
- if (sweepFlag === 0 && ang2 > 0) {
- ang2 -= TAU;
- }
- if (sweepFlag === 1 && ang2 < 0) {
- ang2 += TAU;
- }
- return [centerx, centery, ang1, ang2];
- };
- var arcToBezier = function (_a) {
- var px = _a.px, py = _a.py, cx = _a.cx, cy = _a.cy, rx = _a.rx, ry = _a.ry, _b = _a.xAxisRotation, xAxisRotation = _b === void 0 ? 0 : _b, _c = _a.largeArcFlag, largeArcFlag = _c === void 0 ? 0 : _c, _d = _a.sweepFlag, sweepFlag = _d === void 0 ? 0 : _d;
- var curves = [];
- if (rx === 0 || ry === 0) {
- return [{ x1: 0, y1: 0, x2: 0, y2: 0, x: cx, y: cy }];
- }
- var sinphi = Math.sin(xAxisRotation * TAU / 360);
- var cosphi = Math.cos(xAxisRotation * TAU / 360);
- var pxp = cosphi * (px - cx) / 2 + sinphi * (py - cy) / 2;
- var pyp = -sinphi * (px - cx) / 2 + cosphi * (py - cy) / 2;
- if (pxp === 0 && pyp === 0) {
- return [{ x1: 0, y1: 0, x2: 0, y2: 0, x: cx, y: cy }];
- }
- rx = Math.abs(rx);
- ry = Math.abs(ry);
- var lambda = Math.pow(pxp, 2) / Math.pow(rx, 2) +
- Math.pow(pyp, 2) / Math.pow(ry, 2);
- if (lambda > 1) {
- rx *= Math.sqrt(lambda);
- ry *= Math.sqrt(lambda);
- }
- var _e = getArcCenter(px, py, cx, cy, rx, ry, largeArcFlag, sweepFlag, sinphi, cosphi, pxp, pyp), centerx = _e[0], centery = _e[1], ang1 = _e[2], ang2 = _e[3];
- // If 'ang2' == 90.0000000001, then `ratio` will evaluate to
- // 1.0000000001. This causes `segments` to be greater than one, which is an
- // unecessary split, and adds extra points to the bezier curve. To alleviate
- // this issue, we round to 1.0 when the ratio is close to 1.0.
- var ratio = Math.abs(ang2) / (TAU / 4);
- if (Math.abs(1.0 - ratio) < 0.0000001) {
- ratio = 1.0;
- }
- var segments = Math.max(Math.ceil(ratio), 1);
- ang2 /= segments;
- for (var i = 0; i < segments; i++) {
- curves.push(approxUnitArc(ang1, ang2));
- ang1 += ang2;
- }
- return curves.map(function (curve) {
- var _a = mapToEllipse(curve[0], rx, ry, cosphi, sinphi, centerx, centery), x1 = _a.x, y1 = _a.y;
- var _b = mapToEllipse(curve[1], rx, ry, cosphi, sinphi, centerx, centery), x2 = _b.x, y2 = _b.y;
- var _c = mapToEllipse(curve[2], rx, ry, cosphi, sinphi, centerx, centery), x = _c.x, y = _c.y;
- return { x1: x1, y1: y1, x2: x2, y2: y2, x: x, y: y };
- });
- };
- function arcToCubic(x1, y1, rx, ry, angle, LAF, SF, x2, y2) {
- var curves = arcToBezier({
- px: x1,
- py: y1,
- cx: x2,
- cy: y2,
- rx: rx,
- ry: ry,
- xAxisRotation: angle,
- largeArcFlag: LAF,
- sweepFlag: SF,
- });
- return curves.reduce(function (prev, cur) {
- var x1 = cur.x1, y1 = cur.y1, x2 = cur.x2, y2 = cur.y2, x = cur.x, y = cur.y;
- prev.push(x1, y1, x2, y2, x, y);
- return prev;
- }, []);
- }
- exports.arcToCubic = arcToCubic;
- //# sourceMappingURL=arc-2-cubic.js.map
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