129 lines
3.3 KiB
JavaScript
129 lines
3.3 KiB
JavaScript
"use strict";
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const TypoGeom = require("typo-geom");
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const Point = require("./point");
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const Transform = require("./transform");
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exports.GEOMETRY_PRECISION = 1 / 4;
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exports.RECIP_GEOMETRY_PRECISION = 4;
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exports.BOOLE_RESOLUTION = 0x4000;
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exports.OffsetCurve = class OffsetCurve {
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constructor(bone, offset, contrast) {
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this.bone = bone;
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this.offset = offset;
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this.contrast = contrast;
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}
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eval(t) {
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const c = this.bone.eval(t);
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const d = this.bone.derivative(t);
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const absD = Math.hypot(d.x, d.y);
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return {
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x: c.x - (d.y / absD) * this.offset * this.contrast,
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y: c.y + (d.x / absD) * this.offset
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};
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}
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derivative(t) {
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const DELTA = 1 / 0x10000;
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const forward = this.eval(t + DELTA);
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const backward = this.eval(t - DELTA);
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return {
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x: (forward.x - backward.x) / (2 * DELTA),
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y: (forward.y - backward.y) / (2 * DELTA)
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};
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}
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};
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exports.convertShapeToArcs = function convertShapeToArcs(shape) {
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return shape.map(convertContourToArcs);
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};
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function convertContourToArcs(contour) {
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if (!contour || !contour.length) return [];
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const newContour = [];
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let z0 = Point.from(Point.Type.Corner, contour[0]);
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for (let j = 1; j < contour.length; j++) {
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const z = contour[j];
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switch (z.type) {
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case Point.Type.CubicStart: {
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const z1 = z;
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const z2 = contour[j + 1];
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const z3 = contour[j + 2];
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newContour.push(
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new TypoGeom.Arcs.Bez3(
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z0,
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Point.from(Point.Type.CubicStart, z1),
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Point.from(Point.Type.CubicEnd, z2),
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Point.from(Point.Type.Corner, z3)
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)
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);
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z0 = z3;
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j += 2;
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break;
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}
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case Point.Type.Quadratic: {
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const zc = z;
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let zf = contour[j + 1] || contour[0];
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const zfIsCorner = zf.type === Point.Type.contour;
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if (!zfIsCorner) zf = Point.from(Point.Type.Corner, zc).mix(0.5, zf);
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newContour.push(
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new TypoGeom.Arcs.Bez3(
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z0,
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Point.from(Point.Type.CubicStart, z0).mix(2 / 3, zc),
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Point.from(Point.Type.CubicEnd, zf).mix(2 / 3, zc),
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Point.from(Point.Type.Corner, zf)
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)
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);
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z0 = zf;
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if (zfIsCorner) j++;
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break;
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}
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default: {
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newContour.push(
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TypoGeom.Arcs.Bez3.fromStraightSegment(
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new TypoGeom.Arcs.StraightSegment(z0, Point.from(Point.Type.Corner, z))
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)
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);
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z0 = z;
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break;
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}
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}
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}
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return newContour;
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}
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exports.BezToContoursSink = class BezToContoursSink {
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constructor(gizmo) {
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this.gizmo = gizmo || Transform.Id();
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this.contours = [];
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this.lastContour = [];
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}
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beginShape() {}
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endShape() {
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if (this.lastContour.length) {
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this.contours.push(this.lastContour);
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}
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this.lastContour = [];
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}
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moveTo(x, y) {
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this.endShape();
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.Corner, x, y));
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}
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lineTo(x, y) {
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.Corner, x, y));
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}
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curveTo(xc, yc, x, y) {
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.Quadratic, xc, yc));
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.Corner, x, y));
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}
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cubicTo(x1, y1, x2, y2, x, y) {
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.CubicStart, x1, y1));
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.CubicEnd, x2, y2));
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this.lastContour.push(Point.transformedXY(this.gizmo, Point.Type.Corner, x, y));
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}
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};
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