Node-gm circular image crop using Imagemagick - imagemagick

Question

I've been trying to use node-gm + Imagemagick to circular crop an image.
Anyways, here's my attempt at creating a mask using a black circle.
var original = 'app-server/photo.jpg';
var output = 'app-server/photo.png';
var maskPath = 'app-server/photo-mask.png';
gm(original)
.crop(233, 233,29,26)
.resize(80, 80)
.setFormat('png')
.write(output, function (err) {
console.log(err || 'cropped to target size');
gm(output)
.out('-size', '80x80')
.background('black')
.drawCircle(20,20, 0, 0)
.toBuffer('PNG',function (err, buffer) {
console.log(err || 'created circular black mask');
//docs say "a buffer can be passed instead of
//a filepath" but this is apparently false
//and say something unclear about using black/white colors for masking.
//I'm clearly lost
gm(output)
.mask(maskPath)
.write(output, function (err) {
console.log(err || 'applied circular black mask to image');
});
});
});
I'm sure this can be done via some fancy string command concatenation, but despite my lack of image processing prowess, I still want to keep the code clean. I'm really looking for a solution using node-gm functions, preferably with less operations than my attempt (also preferably something that works, unlike mine).
I also tried to chain out the function calls for this command with no success:
https://stackoverflow.com/a/999563/1267778
Note I need to crop at a specific location (w,h,x,y) so these solutions also don't work for me:
node-pngjs
node-circle-image

Answer 1

Got it! After many hours of fiddling, I got exactly what I needed.
gm(originalFilePath)
.crop(233, 233,29,26)
.resize(size, size)
.write(outputFilePath, function(err) {
gm(size, size, 'none')
.fill(outputFilePath)
.drawCircle(size/2,size/2, size/2, 0)
.write(output, function(err) {
console.log(err || 'done');
});
});
I'm using JCrop to allow the user to crop the image on the front-end and pass the coordinates (w,h,x,y) into crop().