Load a (mutable) bitmap into a Canvas and write text over it
Paint p = new Paint();
p.setAntiAlias(true);
p.setTextSize(24);
Bitmap b = Bitmap.createBitmap(256, 256, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
c.drawText("Devoxx", 0.0f, 128.0f, p);