Get the Drawable from a success request on Compose

[metehus]

Is your feature request related to a problem? Please describe.

There's a discussion on #851 about getting the drawable from the rememberImagePainter in order to use on other methods (like getting the color palette) without making another request externally.

The best way of doing that would be using the target from the ImageRequest. But, as seen on the discussion, it is set internally so it's not possible to use that on the image request builder inside the rememberImagePainter

    val painter = rememberImagePainter(
        imageURL,
        builder = {
            target( // target must be null
                onSuccess = {
                    doStuffWithDrawable(it)
                }
            )
        },
    )

Describe the solution you'd like

A solution i see to that would be a callback like the ImageRequest's target on the compose function, like so:

    val painter = rememberImagePainter(
        imageURL,
        callbacks = {
            onSuccess { drawable ->
                doStuffWithDrawable(drawable)
            }
        }
    )

The internal target would pipe the the onStart, onError and onSuccess from the internal target to the callbacks on the remember function.

[brettmcginnis]

I was able to leverage the transform to grab the bitmap https://stackoverflow.com/q/68094647

[colinrtwhite]

This should be easier in 2.0 since listener has the image result. The best way to grab the bitmap currently is to use ((rememberImagePainter(data).state.painter) as? BitmapPainter).bitmap

[metehus]

This should be easier in 2.0 since listener has the image result. The best way to grab the bitmap currently is to use ((rememberImagePainter(data).state.painter) as? BitmapPainter).bitmap

Oh, thats cool and much easier. Is there a way to check when the request is done? maybe checking for changes on the painter and check if it has a successful result?

[colinrtwhite]

@metehus You can use listener(onSuccess = {}) to listen for when the request completes successfully. ImagePainter.state is also a compose state property so your composition will recompose automatically when it changes.

[tipialican]

@colinrtwhite is it possible to access the drawable in onSuccess?

[univeous]

This should be easier in 2.0 since has the image result. The best way to grab the bitmap currently is to use listener``((rememberImagePainter(data).state.painter) as? BitmapPainter).bitmap

Maybe I missed something. Is BitmapPainter have a bitmap property? I can't make this work properly.

[colinrtwhite]

@univeous Ah! Sorry I totally got this wrong and it's not possible to access the bitmap in BitmapPainter. Given the other solutions are hacky, I'm going to push 1.3.3 today which expose the Drawable in ImagePainter.state. That way you'll be able to get the drawable using:

val painter = rememberImagePainter("https://www.example.com/image.jpg")
val drawable = (painter.state.result as? SuccessResult)?.drawable
Image(painter = painter, contentDescription = null)

EDIT: Sorry for the delay. I've held of rolling out the update temporarily to verify that adding this attribute doesn't increase recompositions.