Handling transparency in 6.0.0 Vs. 6.1.0_9c88924_2020.05.06

We have a script for plotting the attached map. The output changes depending on the GMT version used. In particular, we do not seem able to get the transparency of layers working correctly in the latest GMT version (6.1.0_9c88924_2020.05.06 installed on Mac OSX Catalina using brew install --HEAD gmt). Any help would be highly appreciated. Thanks a lot for the fantastic work you do.

There is a known bug in ghostscript 9.51 and 9.52, which can’t handle transparency. Unfortunately, homebrew provides ghostscript 9.52. See https://github.com/GenericMappingTools/gmt/issues/2903 and https://bugs.ghostscript.com/show_bug.cgi?id=702219 for details.

I’m using GMT 6.1.0_9c88924_2020.05.06 and ghostscript 9.50, and the following script gives me a figure with two 50% transparency circles.

gmt begin map
gmt plot -R0/10/0/10 -JX10c -Baf -Sc -W1p -Gblue@50 << EOF
5 5  2c
5 5  5c
gmt end show

Please try to install ghostscript 9.50 and see if it works for you.

Dear Dongdong thank you for the swift and useful feedback. Reverting to gs 9.50 indeed solved the problem. Thanks again. Marco