Add a way to cancel .generateImages()

[martinlexow]

Generating images can take quite a while and users may want to cancel the progress. Adding a way to abort .generateImages() would be a great benefit.

[godly-devotion]

I've been having this issue as well. I've tried many things from canceling the DispatchQueue where generateImages() was called, calling unloadResources() in the pipeline, etc but none of them works.

[JustinMeans]

Should generateImages() be made async? If so we can Task.checkCancellation() on each iteration.

[godly-devotion]

@JustinMeans That would be helpful. Not sure if this is the best method but this is how I am currently calling it.

[ynagatomo]

How about using progress handler, just return false to cancel the image generation?

nonisolated func progressHandler(progress: StableDiffusionPipeline.Progress) -> Bool {...}

[godly-devotion]

@ynagatomo Just tested, that works too 👍 An official solution would be nice though as it does trigger the error handler. Also having the continueGeneration bool is slightly ugly haha.

let images = try pipeline.generateImages(
    prompt: prompt,
    negativePrompt: negativePrompt,
    imageCount: batchSize,
    stepCount: stepCount,
    seed: seed,
    guidanceScale: guidanceScale,
    disableSafety: true,
    scheduler: scheduler
) { progress in
    return handleProgress(progress)
}

private func handleProgress(_ progress: StableDiffusionPipeline.Progress) -> Bool {
    self.progress = progress
    return continueGeneration
}

[sindresorhus]

I agree that .generateImages() should be async. Also, then the progress closure wouldn't need to return a boolean either as it could just respect Task cancellation internally.