Using Inkscape,Type your text, select object to path, select path effect editor, there are several options to choose from which most I don't know how to use, but you can use the bend option, or the envelope deformation, once you alter your text with either of these tools, select object to path again and it will stay that way, you can pull up or down to fill your shape, takes a little practice, youtube is alot of help, search Inkscape, there are alot of videos, hope this all makes a little sense.