Feature scanIterator

[ghost]

What's Changing and Why

Currently with image.scan it's possible to iterate over the image with a callback

But on some cases it's better if it would possible to iterate with a for loop, like:

for (const { x, y, idx, image } of image.scanIterator(0, 0, image.bitmap.width, image.bitmap.height)) {
    ...
}

An advantage would be too, it's possible to abort the scan with break;, with the callback this is not possible (currently)

What else might be affected

I also change image.scan to use internal the new scanIterator and call the callback

Tasks

• Add tests
• Update Documentation
• Update jimp.d.ts
• Add SemVer Label

[hipstersmoothie]

Does this have any performance implications? I'd be hesitant to make this the default if it makes things slower since scan is used by almost every function.

[ghost]

@hipstersmoothie Thanks for your hint

I made some measuring tests (10000px x 10000px Jimp image) and I take values like:

Measure scanCallback: 500ms
Measure scanCallbackWithIterator: 2933ms
Measure scanIterator: 2338ms

So you're right and the iterator is very slow and I revert the scan function change

[hipstersmoothie]

Can you add some docs to the jimp package's README? Please make sure to note the performance implication.

[hipstersmoothie]

🚀 PR was released in v0.7.0 🚀