I am trying to collect a signature from the user and save it to an image. I have made it far enough that I can draw on the screen, but now I\'d like to click a button to sav
You can capture the output of a CustomPainter with PictureRecorder. Pass your PictureRecorder instance to the constructor for your Canvas. The Picture returned by PictureRecorder.endRecording can then be converted to an Image with Picture.toImage. Finally, extract the image bytes using Image.toByteData.
Here's an example: https://github.com/rxlabz/flutter_canvas_to_image