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- /**
- * @author Yi Shen(https://github.com/pissang)
- */
- import * as vec2 from './vector';
- import * as curve from './curve';
- const mathMin = Math.min;
- const mathMax = Math.max;
- const mathSin = Math.sin;
- const mathCos = Math.cos;
- const PI2 = Math.PI * 2;
- const start = vec2.create();
- const end = vec2.create();
- const extremity = vec2.create();
- /**
- * 从顶点数组中计算出最小包围盒,写入`min`和`max`中
- */
- export function fromPoints(points: ArrayLike<number>[], min: vec2.VectorArray, max: vec2.VectorArray) {
- if (points.length === 0) {
- return;
- }
- let p = points[0];
- let left = p[0];
- let right = p[0];
- let top = p[1];
- let bottom = p[1];
- for (let i = 1; i < points.length; i++) {
- p = points[i];
- left = mathMin(left, p[0]);
- right = mathMax(right, p[0]);
- top = mathMin(top, p[1]);
- bottom = mathMax(bottom, p[1]);
- }
- min[0] = left;
- min[1] = top;
- max[0] = right;
- max[1] = bottom;
- }
- export function fromLine(
- x0: number, y0: number, x1: number, y1: number,
- min: vec2.VectorArray, max: vec2.VectorArray
- ) {
- min[0] = mathMin(x0, x1);
- min[1] = mathMin(y0, y1);
- max[0] = mathMax(x0, x1);
- max[1] = mathMax(y0, y1);
- }
- const xDim: number[] = [];
- const yDim: number[] = [];
- /**
- * 从三阶贝塞尔曲线(p0, p1, p2, p3)中计算出最小包围盒,写入`min`和`max`中
- */
- export function fromCubic(
- x0: number, y0: number, x1: number, y1: number, x2: number, y2: number, x3: number, y3: number,
- min: vec2.VectorArray, max: vec2.VectorArray
- ) {
- const cubicExtrema = curve.cubicExtrema;
- const cubicAt = curve.cubicAt;
- let n = cubicExtrema(x0, x1, x2, x3, xDim);
- min[0] = Infinity;
- min[1] = Infinity;
- max[0] = -Infinity;
- max[1] = -Infinity;
- for (let i = 0; i < n; i++) {
- const x = cubicAt(x0, x1, x2, x3, xDim[i]);
- min[0] = mathMin(x, min[0]);
- max[0] = mathMax(x, max[0]);
- }
- n = cubicExtrema(y0, y1, y2, y3, yDim);
- for (let i = 0; i < n; i++) {
- const y = cubicAt(y0, y1, y2, y3, yDim[i]);
- min[1] = mathMin(y, min[1]);
- max[1] = mathMax(y, max[1]);
- }
- min[0] = mathMin(x0, min[0]);
- max[0] = mathMax(x0, max[0]);
- min[0] = mathMin(x3, min[0]);
- max[0] = mathMax(x3, max[0]);
- min[1] = mathMin(y0, min[1]);
- max[1] = mathMax(y0, max[1]);
- min[1] = mathMin(y3, min[1]);
- max[1] = mathMax(y3, max[1]);
- }
- /**
- * 从二阶贝塞尔曲线(p0, p1, p2)中计算出最小包围盒,写入`min`和`max`中
- */
- export function fromQuadratic(
- x0: number, y0: number, x1: number, y1: number, x2: number, y2: number,
- min: vec2.VectorArray, max: vec2.VectorArray
- ) {
- const quadraticExtremum = curve.quadraticExtremum;
- const quadraticAt = curve.quadraticAt;
- // Find extremities, where derivative in x dim or y dim is zero
- const tx =
- mathMax(
- mathMin(quadraticExtremum(x0, x1, x2), 1), 0
- );
- const ty =
- mathMax(
- mathMin(quadraticExtremum(y0, y1, y2), 1), 0
- );
- const x = quadraticAt(x0, x1, x2, tx);
- const y = quadraticAt(y0, y1, y2, ty);
- min[0] = mathMin(x0, x2, x);
- min[1] = mathMin(y0, y2, y);
- max[0] = mathMax(x0, x2, x);
- max[1] = mathMax(y0, y2, y);
- }
- /**
- * 从圆弧中计算出最小包围盒,写入`min`和`max`中
- */
- export function fromArc(
- x: number, y: number, rx: number, ry: number, startAngle: number, endAngle: number, anticlockwise: boolean,
- min: vec2.VectorArray, max: vec2.VectorArray
- ) {
- const vec2Min = vec2.min;
- const vec2Max = vec2.max;
- const diff = Math.abs(startAngle - endAngle);
- if (diff % PI2 < 1e-4 && diff > 1e-4) {
- // Is a circle
- min[0] = x - rx;
- min[1] = y - ry;
- max[0] = x + rx;
- max[1] = y + ry;
- return;
- }
- start[0] = mathCos(startAngle) * rx + x;
- start[1] = mathSin(startAngle) * ry + y;
- end[0] = mathCos(endAngle) * rx + x;
- end[1] = mathSin(endAngle) * ry + y;
- vec2Min(min, start, end);
- vec2Max(max, start, end);
- // Thresh to [0, Math.PI * 2]
- startAngle = startAngle % (PI2);
- if (startAngle < 0) {
- startAngle = startAngle + PI2;
- }
- endAngle = endAngle % (PI2);
- if (endAngle < 0) {
- endAngle = endAngle + PI2;
- }
- if (startAngle > endAngle && !anticlockwise) {
- endAngle += PI2;
- }
- else if (startAngle < endAngle && anticlockwise) {
- startAngle += PI2;
- }
- if (anticlockwise) {
- const tmp = endAngle;
- endAngle = startAngle;
- startAngle = tmp;
- }
- // const number = 0;
- // const step = (anticlockwise ? -Math.PI : Math.PI) / 2;
- for (let angle = 0; angle < endAngle; angle += Math.PI / 2) {
- if (angle > startAngle) {
- extremity[0] = mathCos(angle) * rx + x;
- extremity[1] = mathSin(angle) * ry + y;
- vec2Min(min, extremity, min);
- vec2Max(max, extremity, max);
- }
- }
- }
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