Javascript检查鼠标在圆形或多边形内单击 [英] Javascript check Mouse clicked inside the Circle or Polygon

问题描述

任何人都知道如何检查在圆圈或多边形内单击鼠标的方法。我的问题是我想检查一下，如果鼠标已经在圆圈或多边形内部被克隆了。圆或多边形坐标已存储在数组中。非常感谢任何帮助

Any one know how to check that wheter a mouse is clicked inside the circle or polygon. My problem is I want to check that if mouse has been clciked inside the circle or polygon. circle or polygon coordinates has been stored inside an array. Any help is really appreciated

推荐答案

正如其他一些答案，我按照一些链接和在这里找到了c代码。
这是用于查找点是否在多边形中的JavaScript转换

As suggested by some other answers, I followed some links and found the c code here. Here is the JavaScript translation for finding whether a point is in a polygon

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function pnpoly( nvert, vertx, verty, testx, testy ) {
    var i, j, c = false;
    for( i = 0, j = nvert-1; i < nvert; j = i++ ) {
        if( ( ( verty[i] > testy ) != ( verty[j] > testy ) ) &&
            ( testx < ( vertx[j] - vertx[i] ) * ( testy - verty[i] ) / ( verty[j] - verty[i] ) + vertx[i] ) ) {
                c = !c;
        }
    }
    return c;
}

nvert - 多边形中的顶点数。是否在末尾重复第一个顶点将在下面讨论。

vertx，verty - 包含多边形顶点的x坐标和y坐标的数组。

testx，testy - 测试点的X和y坐标。

nvert - Number of vertices in the polygon. Whether to repeat the first vertex at the end is discussed below.
vertx, verty - Arrays containing the x- and y-coordinates of the polygon's vertices.
testx, testy - X- and y-coordinate of the test point.

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