I'm using this script on the body onmousemove
function:
function lineDraw() {
// Get the context and the canvas:
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext("2d");
// Clear the last canvas
context.clearRect(0, 0, canvas.width, canvas.height);
// Draw the line:
context.moveTo(0, 0);
context.lineTo(event.clientX, event.clientY);
context.stroke();
}
It's supposed to clear the canvas each time I move the mouse around, and draw a new line, but it isn't working properly. I'm trying to solve it without using jQuery, mouse listeners or similar.
Here is a demo: https://jsfiddle.net/0y4wf31k/
You should use "beginPath()". That is it.
Be advised that ctx.clearRect() does not work properly on Google Chrome. I spent hours trying to solve a related problem, only to find that on Chrome, instead of filling the rectangle with rgba(0, 0, 0, 0), it actually fills the rectangle with rgba(0, 0, 0, 1) instead!
Consequently, in order to have the rectangle filled properly with the required transparent black pixels, you need, on Chrome, to do this instead:
This should, of course, work on all browsers providing proper support for the HTML5 Canvas object.
Try with
context.canvas.width = context.canvas.width
:Demo HERE