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在看zrender源码时,看到点在多边形内的判断代码,特意粘出来,参考下:
/** * 多边形包含判断 * 采用 non-zero winding rule */ function isInsidePolygon(points, x, y) { var N = points.length; var w = 0; for (var i = 0, j = N - 1; i < N; i++) { var x0 = points[j][0]; var y0 = points[j][1]; var x1 = points[i][0]; var y1 = points[i][1]; w += windingLine(x0, y0, x1, y1, x, y); j = i; } return w !== 0; } function windingLine(x0, y0, x1, y1, x, y) { if ((y > y0 && y > y1) || (y < y0 && y < y1)) { return 0; } if (y1 == y0) { return 0; } var dir = y1 < y0 ? 1 : -1; var t = (y - y0) / (y1 - y0); var x_ = t * (x1 - x0) + x0; return x_ > x ? dir : 0; }
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原文地址:http://www.cnblogs.com/lydialee/p/5064864.html