getBitmap

Gets the bitmap used for rendering the image signature, or null if the signature is not an image signature.

NOTE: The returned bitmap is kept in memory in a hash map but this method is meant to be used as an auxiliary method for adding the signature to the document. The bitmap may be destroyed when the app is in background and the system kills the process because needs to release memory resources. This method does not guarantee persistence, to implement this kind of use case it's better to rely on a database, or a cache mechanism that stores the bitmap in the local storage.