How to create a transparent image

Hello,

I’m trying to create a blank transparent Jimp image, but it always has a color value. I tried using the opacity method, but it doesn’t seem to work.

Here is my code:

var mainImage = new Jimp(caseWidth, caseHeight, function (err, image) {
     image.opacity(0, function(err, image) {
          image.write(caseImage);
     });
});

It creates the new image, but it is all black and will not become transparent. I have tried using both the mainImage and reading the caseImage again, but they are both all black.

Is there something I am missing?

Thanks.

[mikechuck]

Turns out you can’t have a transparent jpg… Thanks!

[netux]

You can add an optional background color argument to the Jimp constructor:

var mainImage = new Jimp(caseWidth, caseHeight, 0x0, function (err, image) {
    // do stuff with image
});

(0x0 = 0 = rgba(0, 0, 0, 0))