@antv/util
Version:
> AntV 底层依赖的工具库，不建议在自己业务中使用。
73 lines • 2.66 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.segmentQuadFactory = segmentQuadFactory;
var distance_square_root_1 = require("./distance-square-root");
/**
* Returns the {x,y} coordinates of a point at a
* given length of a quadratic-bezier segment.
*
* @see https://github.com/substack/point-at-length
*/
function getPointAtQuadSegmentLength(x1, y1, cx, cy, x2, y2, t) {
var t1 = 1 - t;
return {
x: Math.pow(t1, 2) * x1 + 2 * t1 * t * cx + Math.pow(t, 2) * x2,
y: Math.pow(t1, 2) * y1 + 2 * t1 * t * cy + Math.pow(t, 2) * y2,
};
}
/**
* Returns a {x,y} point at a given length, the total length and
* the minimum and maximum {x,y} coordinates of a Q (quadratic-bezier) segment.
*/
function segmentQuadFactory(x1, y1, qx, qy, x2, y2, distance, options) {
var _a;
var _b = options.bbox, bbox = _b === void 0 ? true : _b, _c = options.length, length = _c === void 0 ? true : _c, _d = options.sampleSize, sampleSize = _d === void 0 ? 10 : _d;
var distanceIsNumber = typeof distance === 'number';
var x = x1;
var y = y1;
var LENGTH = 0;
var prev = [x, y, LENGTH];
var cur = [x, y];
var t = 0;
var POINT = { x: 0, y: 0 };
var POINTS = [{ x: x, y: y }];
if (distanceIsNumber && distance <= 0) {
POINT = { x: x, y: y };
}
for (var j = 0; j <= sampleSize; j += 1) {
t = j / sampleSize;
(_a = getPointAtQuadSegmentLength(x1, y1, qx, qy, x2, y2, t), x = _a.x, y = _a.y);
if (bbox) {
POINTS.push({ x: x, y: y });
}
if (length) {
LENGTH += (0, distance_square_root_1.distanceSquareRoot)(cur, [x, y]);
}
cur = [x, y];
if (distanceIsNumber && LENGTH >= distance && distance > prev[2]) {
var dv = (LENGTH - distance) / (LENGTH - prev[2]);
POINT = {
x: cur[0] * (1 - dv) + prev[0] * dv,
y: cur[1] * (1 - dv) + prev[1] * dv,
};
}
prev = [x, y, LENGTH];
}
/* istanbul ignore else */
if (distanceIsNumber && distance >= LENGTH) {
POINT = { x: x2, y: y2 };
}
return {
length: LENGTH,
point: POINT,
min: {
x: Math.min.apply(null, POINTS.map(function (n) { return n.x; })),
y: Math.min.apply(null, POINTS.map(function (n) { return n.y; })),
},
max: {
x: Math.max.apply(null, POINTS.map(function (n) { return n.x; })),
y: Math.max.apply(null, POINTS.map(function (n) { return n.y; })),
},
};
}
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