Please provide a way to change zoom and offset programatically

[MitulVarmora]

I am building an app in which I would like to save user's last zoom and offset and restore it when user revisit same image.
As of now lib version 0.8.0: There is no way to change zoom and offset programatically.

Please provide a way to change zoom and offset programatically.
This is important to my app because that way user will continue editing image from where they left.

[saket]

That's a very interesting usecase!

I would like to save user's last zoom and offset

What value do you plan to save? ZoomableState#zoomFraction or ZoomableState#contentTransformation?

[MitulVarmora]

What value do you plan to save? ZoomableState#zoomFraction or ZoomableState#contentTransformation?

ZoomableState#contentTransformation because thats what contains offset and scale both.

[Tlaster]

Another application involves utilizing PredictiveBackHandler to animate zoom scale and offset, such as scaling back to the original size when the user presses the back button with predictive back functionality.

[saket]

@Tlaster can you use ZoomableState#resetZoom() for that?

[Tlaster]

@Tlaster can you use ZoomableState#resetZoom() for that?

ZoomableState#resetZoom() will reset the zoom instantly, with PredictiveBackHandler we can get a progress that indicate how many "back" user has been dragged, so we can use the progress to set the scale and offset programmatically. For more about predictive back: https://developer.android.com/guide/navigation/custom-back/predictive-back-gesture

[saket]

@Tlaster interesting. Is there a reason you want to change the scale/offset on every frame during the back gesture? I haven't seen any apps do that.

[Tlaster]

@Tlaster interesting. Is there a reason you want to change the scale/offset on every frame during the back gesture? I haven't seen any apps do that.

Just a thought, like a gallery app when user scale up a photo then want to reset the scale by back gesture, it would be nice to have an animation during back gesture.