@mapgis/webclient-es6-mapboxgl/theme/common/overlay/levelRender/ComputeBoundingBox.js

import { Common } from '@mapgis/webclient-es6-service';
const { Zondy } = Common;
import {Curve as LevelRendererCurve} from './Curve';
import {Vector as LevelRendererVector} from './Vector';

/**
 * @private
 * @class  Zondy.LevelRenderer.Tool.ComputeBoundingBox
 * @classdesc LevelRenderer 工具-图形 Bounds 计算
 */
class ComputeBoundingBox {

    /**
     * @function Zondy.LevelRenderer.Tool.ComputeBoundingBox.prototype.constructor
     * @description 构造函数。
     */
    constructor() {
        if (arguments.length === 3) {
            this.computeBoundingBox(arguments);
        }

        this.CLASS_NAME = "Zondy.LevelRenderer.Tool.ComputeBoundingBox";
    }

    /**
     * @function Zondy.LevelRenderer.Tool.ComputeBoundingBox.prototype.computeBoundingBox
     * @description 从顶点数组中计算出最小包围盒，写入'min'和'max'中。
     * @param {Array.<Object>} points - 顶点数组。
     * @param {Array} min - 最小
     * @param {Array} max - 最大
     */
    computeBoundingBox(points, min, max) {
        if (points.length === 0) {
            return;
        }
        var left = points[0][0];
        var right = points[0][0];
        var top = points[0][1];
        var bottom = points[0][1];

        for (var i = 1; i < points.length; i++) {
            var p = points[i];
            if (p[0] < left) {
                left = p[0];
            }
            if (p[0] > right) {
                right = p[0];
            }
            if (p[1] < top) {
                top = p[1];
            }
            if (p[1] > bottom) {
                bottom = p[1];
            }
        }

        min[0] = left;
        min[1] = top;
        max[0] = right;
        max[1] = bottom;
    }

    /**
     * @function Zondy.LevelRenderer.Tool.ComputeBoundingBox.prototype.cubeBezier
     * @description 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。原：computeCubeBezierBoundingBox。
     * @param {Array.<number>} p0 - 三阶贝塞尔曲线p0点
     * @param {Array.<number>} p1 - 三阶贝塞尔曲线p1点
     * @param {Array.<number>} p2 - 三阶贝塞尔曲线p2点
     * @param {Array.<number>} p3 - 三阶贝塞尔曲线p3点
     * @param {Array.<number>} min - 最小
     * @param {Array.<number>} max - 最大
     */
    cubeBezier(p0, p1, p2, p3, min, max) {
        var curve = new LevelRendererCurve();

        var xDim = [];
        curve.cubicExtrema(p0[0], p1[0], p2[0], p3[0], xDim);
        for (let i = 0; i < xDim.length; i++) {
            xDim[i] = curve.cubicAt(p0[0], p1[0], p2[0], p3[0], xDim[i]);
        }
        var yDim = [];
        curve.cubicExtrema(p0[1], p1[1], p2[1], p3[1], yDim);
        for (let i = 0; i < yDim.length; i++) {
            yDim[i] = curve.cubicAt(p0[1], p1[1], p2[1], p3[1], yDim[i]);
        }

        xDim.push(p0[0], p3[0]);
        yDim.push(p0[1], p3[1]);

        var left = Math.min.apply(null, xDim);
        var right = Math.max.apply(null, xDim);
        var top = Math.min.apply(null, yDim);
        var bottom = Math.max.apply(null, yDim);

        min[0] = left;
        min[1] = top;
        max[0] = right;
        max[1] = bottom;
    }

    /**
     * @function Zondy.LevelRenderer.Tool.ComputeBoundingBox.prototype.quadraticBezier
     * @description 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。原：computeQuadraticBezierBoundingBox。
     * @param {Array.<number>} p0 - 二阶贝塞尔曲线p0点
     * @param {Array.<number>} p1 - 二阶贝塞尔曲线p1点
     * @param {Array.<number>} p2 - 二阶贝塞尔曲线p2点
     * @param {Array.<number>} min - 最小
     * @param {Array.<number>} max - 最大
     */
    quadraticBezier(p0, p1, p2, min, max) {
        var curve = new LevelRendererCurve();

        // Find extremities, where derivative in x dim or y dim is zero
        var t1 = curve.quadraticExtremum(p0[0], p1[0], p2[0]);
        var t2 = curve.quadraticExtremum(p0[1], p1[1], p2[1]);

        t1 = Math.max(Math.min(t1, 1), 0);
        t2 = Math.max(Math.min(t2, 1), 0);

        var ct1 = 1 - t1;
        var ct2 = 1 - t2;

        var x1 = ct1 * ct1 * p0[0]
            + 2 * ct1 * t1 * p1[0]
            + t1 * t1 * p2[0];
        var y1 = ct1 * ct1 * p0[1]
            + 2 * ct1 * t1 * p1[1]
            + t1 * t1 * p2[1];

        var x2 = ct2 * ct2 * p0[0]
            + 2 * ct2 * t2 * p1[0]
            + t2 * t2 * p2[0];
        var y2 = ct2 * ct2 * p0[1]
            + 2 * ct2 * t2 * p1[1]
            + t2 * t2 * p2[1];
        min[0] = Math.min(p0[0], p2[0], x1, x2);
        min[1] = Math.min(p0[1], p2[1], y1, y2);
        max[0] = Math.max(p0[0], p2[0], x1, x2);
        max[1] = Math.max(p0[1], p2[1], y1, y2);
    }

    /**
     * @function Zondy.LevelRenderer.Tool.ComputeBoundingBox.prototype.arc
     * @description 从圆弧中计算出最小包围盒，写入'min'和'max'中。原：computeArcBoundingBox。
     * @param {number} x - 圆弧中心点 x
     * @param {number} y - 圆弧中心点 y
     * @param {number} r - 圆弧半径
     * @param {number} startAngle - 圆弧开始角度
     * @param {number} endAngle - 圆弧结束角度
     * @param {number} anticlockwise - 是否是顺时针
     * @param {number} min - 最小
     * @param {number} max - 最大
     */
    arc(x, y, r, startAngle, endAngle, anticlockwise, min, max) {
        var vec2 = new LevelRendererVector();

        var start = vec2.create();
        var end = vec2.create();
        var extremity = vec2.create();

        start[0] = Math.cos(startAngle) * r + x;
        start[1] = Math.sin(startAngle) * r + y;

        end[0] = Math.cos(endAngle) * r + x;
        end[1] = Math.sin(endAngle) * r + y;

        vec2.min(min, start, end);
        vec2.max(max, start, end);

        // Thresh to [0, Math.PI * 2]
        startAngle = startAngle % (Math.PI * 2);
        if (startAngle < 0) {
            startAngle = startAngle + Math.PI * 2;
        }
        endAngle = endAngle % (Math.PI * 2);
        if (endAngle < 0) {
            endAngle = endAngle + Math.PI * 2;
        }

        if (startAngle > endAngle && !anticlockwise) {
            endAngle += Math.PI * 2;
        } else if (startAngle < endAngle && anticlockwise) {
            startAngle += Math.PI * 2;
        }
        if (anticlockwise) {
            var tmp = endAngle;
            endAngle = startAngle;
            startAngle = tmp;
        }

        // var number = 0;
        // var step = (anticlockwise ? -Math.PI : Math.PI) / 2;
        for (var angle = 0; angle < endAngle; angle += Math.PI / 2) {
            if (angle > startAngle) {
                extremity[0] = Math.cos(angle) * r + x;
                extremity[1] = Math.sin(angle) * r + y;

                vec2.min(min, extremity, min);
                vec2.max(max, extremity, max);
            }
        }
    }
}

export {ComputeBoundingBox};
Zondy.LevelRenderer.Tool.ComputeBoundingBox = ComputeBoundingBox;