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Edit LineTo Points (in Canvas)

- 1 answer

I want to move lineTo points.
How to do it?
I'm new to Canvas.
I'll give an example with Path.

This is my example:

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.beginPath();
ctx.moveTo(20, 20);
var line = ctx.lineTo(300, 100);
ctx.lineTo(70, 100);
ctx.lineTo(20, 20);
ctx.fillStyle = "red";
ctx.fill();
setTimeout(function() {
  /*
            I want something like this:
            line.editpoints(300, 150);
            */
}, 3000);
<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;"></canvas>

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Answer

Well, canvas as the name suggests, is a canvas (just like in paintings). You can draw on it, but you cannot move things on it as it is not "dynamic".

What you can do, though, is clear it and then draw on top at a different location.

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");

function clearContext(ctx) {
  ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
}

function drawTriangle(offsetX = 0, offsetY = 0) {
  ctx.beginPath();
  ctx.moveTo(offsetX + 20, offsetY + 20);
  var line = ctx.lineTo(offsetX + 300, offsetY + 100);
  ctx.lineTo(offsetX + 70, offsetY + 100);
  ctx.lineTo(offsetX + 20, offsetY + 20);
  ctx.fillStyle = "red";
  ctx.fill();
}
drawTriangle();

setTimeout(function() {
  clearContext(ctx);
  drawTriangle(50, 50);
}, 3000);
<canvas id="myCanvas" width="400" height="400" style="border:1px solid #d3d3d3;"></canvas>

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source: stackoverflow.com
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