Conversion of RGB to CMYK image using Icc profiles

[necessarylion]

Hi, I have a magick command that convert rgb image to cmyk with icc profiles.

magick test.webp  -profile input/sRGB.icc -profile output/CoatedFOGRA39.icc  -colorspace cmyk test_out.jpg

And I am looking for similar code in javascript.

Currently, this is what I have so far but the output color is not exactly what I got from upper command. (eg. light green become dark green)

const data = await urlToUint8Array('test.webp')
const rgb = await urlToUint8Array('input/sRGB.icc')
const cmyk = await urlToUint8Array('output/CoatedFOGRA39.icc')
ImageMagick.read(data, (image) => {

    image.setProfile('rgb', rgb)
    image.colorSpace = ColorSpace.CMYK
    image.setProfile('CoatedFOGRA39', cmyk)
    
    image.write(MagickFormat.Jpg, async (imageData: Uint8Array) => {
       // code to download image
    });
})

async function urlToUint8Array(url: string) {
  const response = await fetch(url);
  if (!response.ok) throw new Error('failed to fetch')
  const arrayBuffer = await response.arrayBuffer();
  return new Uint8Array(arrayBuffer);
}

[dlemstra]

There is not yet a public api available for this but it I can add support for this in the next release. Might take a couple days before I have time to work on this and I can probably publish a new release after that.

[necessarylion]

Thanks. Looking forward to it.

[dlemstra]

I just pushed a commit that adds transformColorSpace to MagickImage and this will become available in the next release.

[dlemstra]

The new release has just been published.

[necessarylion]

Thanks @dlemstra, It work perfectly with:

const rgbProfile = new ColorProfile(rgb)
const cmykProfile = new ColorProfile(cmyk)
image.transformColorSpace(rgbProfile, cmykProfile)
image.colorSpace = ColorSpace.CMYK

But, if I create color profile with the name new new ColorProfile('rgb', rgb), it throw below error

@imagemagick_magick-…m.js?v=c154409c:413 Uncaught (in promise) K: Invalid profile name: rgb.
at new fu (http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:413:13)
at http://localhost:5173/src/App.vue?t=1733208652270:35:28
at http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:7786:14
at _ce._disposeAfterExecution (http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:888:17)
at _re._use (http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:3055:15)
at _re._create (http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:3058:25)
at _.read (http://localhost:5173/node_modules/.vite/deps/@imagemagick_magick-wasm.js?v=c154409c:7777:15)
at convert (http://localhost:5173/src/App.vue?t=1733208652270:34:19)

[dlemstra]

The name of the profile is invalid. I will improve the exception message but only icc and icm are allowed. When you do new ColorProfile(rgb) it will use icc as the profile name.

[necessarylion]

Ahh Got it. So, name is like color profile type.
May be enum Type would be great instead of string?

[dlemstra]

Yeah that might be a good improvement but most people will probably only use the one where you don't provide a name. Not sure if I want to add a new enumeration. I could probably do this instead: constructor(name: 'icc' | 'icm', data: Uint8Array)

[dlemstra]

Decided to solve it with this: abfa06f