Programmatically use RGBa values in fillStyle in ?

Question

Using , I want to set the RGBa value of the rectangle using a variable.

for example:

ctx.fillStyle = \"rgba(32, 45, 21, 0         


        

Answer 1

I'm very late to the party but I had a similar problem and solved it in a slightly different way that may be useful.

Since I needed to reuse the fill colours at different alpha levels, I used the JavaScript replace method:

colurfill = "rgba(255, 255, 0, [[opacity]])";
ctx.fillStyle = colurfill.replace("[[opacity]]", "0.5");
:
:
ctx.fillStyle = colurfill.replace("[[opacity]]", "0.75");

Obviously it doesn't have to be the alpha level that varies, it could be one of the other channels.