Refactor: Render Markup Layers natively on full-resolution bitmap to prevent quality loss #2571
Description
Is your feature request related to a problem? Please describe.
Currently, when a user saves an image from the Markup Layers feature, the app uses captureController.captureAsync() to take a screenshot of the Compose view. While this works for displaying the UI, it causes a significant loss in image quality, as the saved image is constrained by the screen resolution rather than the imported image's original full resolution.
As mentioned by the maintainer, the saving process needs to be moved to the repository level by "projecting all compose operations on a full resolution bitmap."
Describe the solution you'd like
Instead of taking a UI screenshot, we need to mathematically project the Compose layer properties (scale, rotation, offset) onto the original high-resolution Bitmap.
I plan to implement the unfinished native rendering logic inside AndroidMarkupLayersApplier.kt by:
Implementing Canvas.drawLayer() using the native android.graphics.Canvas API.
Translating the LayerPosition parameters (scale, rotation, translation) into native Canvas matrix transformations.
Implementing native drawing logic for LayerType.Text, LayerType.Picture.Image, and LayerType.Picture.Sticker.
Removing the useOldLayers = true fallback in MarkupLayersComponent once the native applier is fully functional.
Describe alternatives you've considered
No response