使用 JSXGraph 绘制不等式域梳状图

Question

我想用不等式域的梳状选择来绘制轴线，如下图：

JSXGraph 可以吗？

Answer 1

它还不是 JSXGraph built-in。但这是个好建议。这是一个实现（要成为 built-in，必须将其重写为 JSXGraph 元素）。

const board = JXG.JSXGraph.initBoard('jxgbox', {
                            boundingbox: [-5, 5, 5, -5],
              axis: true
          });

var comb = function(board, [left, right, n, base, height]) {
    var delta,
        c = board.create('curve', [[0], [0]]);

    delta = (right - left) / n;

    c.updateDataArray = function() {
        var s;

        this.dataX = [];
        this.dataY = [];
        for (s = left; s + delta*0.5<= right; s += delta) {
            this.dataX.push(s);
            this.dataY.push(base);
            this.dataX.push(s + delta);
            this.dataY.push(base + height);
            this.dataX.push(NaN);  // Force a jump
            this.dataY.push(NaN);
        }
    };

    board.update();

    return c;  
};


var c1 = comb(board, [1, 3, 10, 0, 0.2]);
var c2 = comb(board, [-4, -1, 20, -2, 0.2]);

在此处查看实际效果：https://jsfiddle.net/vcL7aepo/217/ .

使用 JSXGraph 绘制不等式域梳状图

Plotting inequalities domain comb-style with JSXGraph

inequality

jsxgraph

inequalities