Question

Let’s say I draw an HTML5 element of rectangle using this:

context.clearRect(25, 72, 32, 32);

How would I make it 50% transparent?

Answer 1

Use globalAlpha. You’ll also have to draw with fillRect. clearRect just erases pixels. It can’t partially erase so you’ll have to use fillRect or other drawing primitives.

from w3schools.com:

    ctx.globalAlpha = 0.2;
    ctx.fillRect(50,50,75,50);
    ctx.globalAlpha = 1.0;