Hello, Sage community!
I just downloaded the sage-8.9 source code. I tried to compile it with Python 3, but the process stops with an error when trying to install matplotlib. The problem seems to be related to the fact that the installer is looking for libpng12, which is no longer available at Ubuntu 18.04's repositories. I get the following error message:
REQUIRED DEPENDENCIES AND EXTENSIONS
numpy: yes [version 1.16.1]
install_requires: yes [handled by setuptools]
libagg: yes [pkg-config information for 'libagg' could not
be found. Using local copy.]
freetype: yes [version 2.9.1]
png: no [The C/C++ header for libpng (png.h) could not
be found. You may need to install the development
package.]
qhull: yes [pkg-config information for 'libqhull' could not
be found. Using local copy.]
[SOME EXTRA USELESS INFO HERE AND THEN...]
============================================================================
* The following required packages can not be built:
* png
* Try installing png with `apt-get install
* libpng12-dev` and pkg-config with `apt-get install
* pkg-config`
Is there something I can do in the meanwhile?
Thanks in advance!
