Tricks

Konva - making a rectangle with a hole

Konva's clipFunc is usually used to trim off the edges of oversize images. The magic here is that if we draw an outer path clockwise and an inner path counter-clockwise, the area defined by the inner path becomes a hole! Let's look into it...

Konva - Flipping an image in-place

It's easy to find out that to flip an image we can set the scaleX or Y to -1. But there's a problem here because images are based on the rect and have their origin at (0, 0). To make a proper in-place flip we have a little more work to do. Lets take a look...