javascript - 如何在两个或多个点之间画线？ (积分可以动态改变)

Question

我对 d3.js 很陌生，需要一些帮助。我试图在两点之间画一条线。我的问题是一切都应该是动态的，即我们通常遵循告诉 x1 的规则, x2 , y1和y3职位。这是一个例子

var canvas = d3.select("body")
                    .append("svg")
                    .attr("width", 500)
                    .attr("height", 500);

var line = canvas.append("line")
                 .attr("x1", 0) // x1 position
                 .attr("y1", 100) // y1 position
                 .attr("x2", 400) // x2 position
                 .attr("y2", 400) // y2 position
                 .attr("stroke", "green")
                 .attr("stroke-width", 10);

我希望动态创建这些位置，即当我单击网页时，应该创建一个点并将其从该位置拖动并将其放置在其他位置。我怎样才能做到这一点？

谢谢

Answer 1

A line is a simple line between two points and is described by four required attributes.

    x1: The x position of the first end of the line as measured from the left of the screen.
    y1: The y position of the first end of the line as measured from the top of the screen.
    x2: The x position of the second end of the line as measured from the left of the screen.
    y2: The y position of the second end of the line as measured from the top of the screen.

The following is an example of the code section required to draw a line;

holder.append("line")          // attach a line
    .style("stroke", "black")  // colour the line
    .attr("x1", 100)     // x position of the first end of the line
    .attr("y1", 50)      // y position of the first end of the line
    .attr("x2", 300)     // x position of the second end of the line
    .attr("y2", 150);    // y position of the second end of the line

This will produce a line as follows;

enter image description here

The line extends from the point 100,50 to 300,150 (x1,y1 to x2,y2).

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