ImageMagick - Using -distort to create curved text with transparent background

Question

I have a command like this:

convert -font Tahoma -pointsize 20 label:' Around the World ' \
-virtual-pixel Background -background SkyBlue \
-distort Arc 60 arc_circle_1.png

The command will create an image:

The background of the text is white, I want it to be transparent. How can I do that? Tkanks.

Answer 1

Normally, you would do that by setting the undercolor, like this:

convert -undercolor magenta -font Tahoma -pointsize 20 label:' Around the World ' -virtual-pixel Background -background SkyBlue -distort Arc 60  arc_circle_1.png

but for some reason, that doesn't work when you set the undercolour to none or transparent because you can't overdraw with nothing to make something.

All I can suggest for the minute, is that you create the image with the default white undercolour, then make whites transparent:

convert -font Tahoma -pointsize 20 label:' Around the World ' -virtual-pixel Background -background SkyBlue -distort Arc 60 -fuzz 20% -transparent white arc_circle_1.png

If you have whites in your image somewhere, just set the undercolour to fucshia or something very contrasting and later, make that colour transparent.