Question

I have a Bitmap and I want to draw circle or square on it.
Do I need to use canvas or there is possibility to draw on Bitmap?

Answer 1

You use Canvas to draw data into a Bitmap instance, simply by creating a Canvas instance and passing the Bitmap to the constructor. However, the Bitmap must be mutable or you will not be able to edit its pixel data. By default, any Bitmap created by loading an image file, etc. is immutable. You will likely need to use one of the versions of Bitmap.createBitmap() that takes the original as a parameter in order to make a mutable copy you can draw on top of.