Making GLSlideshow Show Comments

Intro: XScreenSaver is a popular collection of screensavers for Mac/Linux. One of these screensavers is GLSlideshow, which can show random pictures from a directory.

I have a gallery of pictures that I wanted GLSlideshow to display. Also, GLSlideshow has a mode where it displays the titles of the picture. I wanted to extend that so it would show the comment as well, to provide some context to whoever's watching the pretty screen saver.

Step 1: Write a script to populate a directory with symbolic links to every picture in the gallery. This part was pretty straightforward.

Step 2: Add the gallery comments to the pictures' metadata. I ended up stuffing the gallery comment (after stripping out formatting) into the EXIF UserComment field.

Step 3: Make GLSlideshow read and display the EXIF UserComment. Since GLSlideshow already has support for display titles, this wasn't too tricky.

Here are the source files. Note that the GLSlideshow files were changed from version 5.44.

• walkgallerypics.py - the Python script that creates the symlinks to the pictures and adds the EXIF UserComment data. Note that you need a file walkgallerysettings.py with variables galleryDbUsername, galleryDbPassword and galleryDb with the username, password, and database name that holds your gallery.
• glslideshow.c - the modified GLSlideshow program. Here's a diff with the stock 5.44 version.
• texfont.c - the modified utility to show partially-transparent backgrounds. Here's a diff with the stock 5.44 version.
• texfont.h - the modified utility to show partially-transparent backgrounds. Here's a diff with the stock 5.44 version.