Javascript/jQuery: remove shape/path from canvas

Question

I can't seem to find the function to remove a shape or path from the canvas after it has been created.

So I'm creating a bezier curve between 2 points with

beginPath();
bezierCurveTo();
stroke();
closePath();

How can I remove this from the canvas once it's been created? I need to be able to call the remove function via toggle() and blur(). I'm sure something exists for this...

Thanks in advance for any help!

Answer 1

Try this:

ctx.save();
ctx.globalCompositeOperation = "destination-out";
// drawing here you path second time
ctx.restore();

"The globalCompositeOperation attribute sets how shapes and images are drawn onto the scratch bitmap" specs

How it works you can see here.

Answer 2

This is an important thing to realise about <canvas>. It's a flattened image made up of pixels. Once something's drawn to it, it's merged into the pixel grid and cannot be differentiated from the other pixels.

If you need to be able to separate image elements you could:

1. Overlay <canvas> elements into a stack of layers
2. Use <svg> in which each visual element is distinct from the other elements and may be manipulated independently

You can think of <canvas> as being a single layer in PhotoShop/Gimp/Fireworks, or an MSPaint document.

You can think of <svg> as a document in Illustrator/InkScape.