selector.js

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/

import * as polygonContain from 'zrender/src/contain/polygon';
import BoundingRect from 'zrender/src/core/BoundingRect';

// Key of the first level is brushType: `line`, `rect`, `polygon`.
// Key of the second level is chart element type: `point`, `rect`.
// See moudule:echarts/component/helper/BrushController
// function param:
//      {Object} itemLayout fetch from data.getItemLayout(dataIndex)
//      {Object} selectors {point: selector, rect: selector, ...}
//      {Object} area {range: [[], [], ..], boudingRect}
// function return:
//      {boolean} Whether in the given brush.
var selector = {
    lineX: getLineSelectors(0),
    lineY: getLineSelectors(1),
    rect: {
        point: function (itemLayout, selectors, area) {
            return itemLayout && area.boundingRect.contain(itemLayout[0], itemLayout[1]);
        },
        rect: function (itemLayout, selectors, area) {
            return itemLayout && area.boundingRect.intersect(itemLayout);
        }
    },
    polygon: {
        point: function (itemLayout, selectors, area) {
            return itemLayout
                && area.boundingRect.contain(itemLayout[0], itemLayout[1])
                && polygonContain.contain(area.range, itemLayout[0], itemLayout[1]);
        },
        rect: function (itemLayout, selectors, area) {
            var points = area.range;

            if (!itemLayout || points.length <= 1) {
                return false;
            }

            var x = itemLayout.x;
            var y = itemLayout.y;
            var width = itemLayout.width;
            var height = itemLayout.height;
            var p = points[0];

            if (polygonContain.contain(points, x, y)
                || polygonContain.contain(points, x + width, y)
                || polygonContain.contain(points, x, y + height)
                || polygonContain.contain(points, x + width, y + height)
                || BoundingRect.create(itemLayout).contain(p[0], p[1])
                || lineIntersectPolygon(x, y, x + width, y, points)
                || lineIntersectPolygon(x, y, x, y + height, points)
                || lineIntersectPolygon(x + width, y, x + width, y + height, points)
                || lineIntersectPolygon(x, y + height, x + width, y + height, points)
            ) {
                return true;
            }
        }
    }
};

function getLineSelectors(xyIndex) {
    var xy = ['x', 'y'];
    var wh = ['width', 'height'];

    return {
        point: function (itemLayout, selectors, area) {
            if (itemLayout) {
                var range = area.range;
                var p = itemLayout[xyIndex];
                return inLineRange(p, range);
            }
        },
        rect: function (itemLayout, selectors, area) {
            if (itemLayout) {
                var range = area.range;
                var layoutRange = [
                    itemLayout[xy[xyIndex]],
                    itemLayout[xy[xyIndex]] + itemLayout[wh[xyIndex]]
                ];
                layoutRange[1] < layoutRange[0] && layoutRange.reverse();
                return inLineRange(layoutRange[0], range)
                    || inLineRange(layoutRange[1], range)
                    || inLineRange(range[0], layoutRange)
                    || inLineRange(range[1], layoutRange);
            }
        }
    };
}

function inLineRange(p, range) {
    return range[0] <= p && p <= range[1];
}

function lineIntersectPolygon(lx, ly, l2x, l2y, points) {
    for (var i = 0, p2 = points[points.length - 1]; i < points.length; i++) {
        var p = points[i];
        if (lineIntersect(lx, ly, l2x, l2y, p[0], p[1], p2[0], p2[1])) {
            return true;
        }
        p2 = p;
    }
}

// Code from <http://blog.csdn.net/rickliuxiao/article/details/6259322> with some fix.
// See <https://en.wikipedia.org/wiki/Line%E2%80%93line_intersection>
function lineIntersect(a1x, a1y, a2x, a2y, b1x, b1y, b2x, b2y) {
    var delta = determinant(a2x - a1x, b1x - b2x, a2y - a1y, b1y - b2y);
    if (nearZero(delta)) { // parallel
        return false;
    }
    var namenda = determinant(b1x - a1x, b1x - b2x, b1y - a1y, b1y - b2y) / delta;
    if (namenda < 0 || namenda > 1) {
        return false;
    }
    var miu = determinant(a2x - a1x, b1x - a1x, a2y - a1y, b1y - a1y) / delta;
    if (miu < 0 || miu > 1) {
        return false;
    }
    return true;
}

function nearZero(val) {
    return val <= (1e-6) && val >= -(1e-6);
}

function determinant(v1, v2, v3, v4) {
    return v1 * v4 - v2 * v3;
}

export default selector;