Now a little question more:
I've an image file (in .PNG for example), and I want to write in it some text and save the image. Which is the best way to do this?? I know that I can save an image with Canvas.Bitmap.WriteToStream, but I don't know how to write some text over this before saving.
I think you are referring to Canvas.DrawText, doesn't it?
Maybe, something like this could work??
B4X:
Dim Bitmap1 As Bitmap
Bitmap1.Initialize(File.DirAssets, "MyImageFile.png")
Dim DestRect As Rect
DestRect.Initialize(10dip, 10dip, 10dip + 100dip, 10dip + 100dip)
Canvas1.DrawBitmap(Bitmap1, Null, DestRect)
Canvas1.DrawText("Sample text.", 200dip, 200dip, Typeface.DEFAULT_BOLD, 30, Colors.Blue, "LEFT")
Dim Out As OutputStream
Out = File.OpenOutput(File.DirRootExternal, "Test.png", False)
Canvas1.Bitmap.WriteToStream(out, 100, "PNG")
Out.Close