zrender/src/contain/line.ts

A lightweight graphic library providing 2d draw for Apache ECharts

/**
 * 线段包含判断
 * @param  {number}  x0
 * @param  {number}  y0
 * @param  {number}  x1
 * @param  {number}  y1
 * @param  {number}  lineWidth
 * @param  {number}  x
 * @param  {number}  y
 * @return {boolean}
 */
export function containStroke(
    x0: number, y0: number, x1: number, y1: number,
    lineWidth: number, x: number, y: number
): boolean {
    if (lineWidth === 0) {
        return false;
    }
    const _l = lineWidth;
    let _a = 0;
    let _b = x0;
    // Quick reject
    if (
        (y > y0 + _l && y > y1 + _l)
        || (y < y0 - _l && y < y1 - _l)
        || (x > x0 + _l && x > x1 + _l)
        || (x < x0 - _l && x < x1 - _l)
    ) {
        return false;
    }

    if (x0 !== x1) {
        _a = (y0 - y1) / (x0 - x1);
        _b = (x0 * y1 - x1 * y0) / (x0 - x1);
    }
    else {
        return Math.abs(x - x0) <= _l / 2;
    }
    const tmp = _a * x - y + _b;
    const _s = tmp * tmp / (_a * _a + 1);
    return _s <= _l / 2 * _l / 2;
}