Is it possible to access the size of a drawing environment? In my specific use case I'm applying the...

# compose

[jonc]

Is it possible to access the size of a drawing environment? In my specific use case I'm applying the graphicsLayer modifier to an Image . I need the size of the image respective to content scale in order to implement some customized gestures. I've tried onSizeChanged and onGloballyPositioned but those seem to be used for the layouts rather than graphics so it isn't called when transformations are made through graphicsLayer

[igor.korotenko]

you could try BoxWithConstraints

[Zach Klippenstein (he/him) [MOD]]

Graphics layer transformations are included in the position and size calculations of a layout node, including all the calculations for pointer input, so if you have the modifier order set up correctly then what you're trying to do should work. Can you share your code?

[jonc]

Was using gestures to scale and rotate this image but so far it looks like onSizeChanged and onGloballyPositioned are only called initially. When scaling, rotating or offsetting the image it's not calling them.

Image(
            modifier = Modifier
                .fillMaxSize()
                .onSizeChanged {
                    Log.v("onSizeChanged", it.toString())
                }
                .onGloballyPositioned {
                    Log.v("onGloballyPositioned", "Parent: " + it.boundsInParent())
                    Log.v("onGloballyPositioned", "Window: " + it.boundsInWindow())
                    Log.v("onGloballyPositioned", "Root: " + it.boundsInRoot())
                }
                .graphicsLayer {
                    scaleX = scale
                    scaleY = scale
                    rotationZ = rotation
                    translationX = offsetX
                    translationY = offsetY
                },
            painter = rememberImagePainter(photoUrl),
            contentDescription = stringResource(id = R.string.close_image)
        )

[jonc]

I could use the initial value and scale to compute the size. One issue though is the sizes are not of the painted image but of layout itself so it doesn't actually match the dimensions of the image.

[Zach Klippenstein (he/him) [MOD]]

Oh, so the values returned by LocalCoordinates should take the layer into account but the callback doesn't happen. I wonder if onPlaced will get invoked for those changes?

[jonc]

I tried that too but didn't seem to get called. It does get called when I use scale and offset modifiers instead but those affect the layout and don't give me the size of the painted image. 😢

[Zach Klippenstein (he/him) [MOD]]

FWIW, https://issuetracker.google.com/226224844

[jonc]

Much appreciated! This will help with future photo galleries built with compose!