Screenshots in LibreOffice Help

An image worth a thousands words.

Indeed, a textual description of a software feature is too often hard to read, but a simple picture tells much about.

So I patched the LibreOffice Math help pages with screenshots taken by the ScreenShot_Test helper designed by bubli and added them to the help pages. To avoid handling images in too many scattered help files, I collected the in a new help file named screenshots.xhp under /06/ folder of the module. This way,  the images are embedded at the right page and if the screenshot has to be modifies, it is enough to edit the screenshot.xhp file instead of the target help file, which by the way can be multiple.

The Math module has only 8 screenshots under the module/ folder so it makes it easy to evaluate the impact on the size of the data. For all the supported languages (--with-lang=ALL) it adds 19M bytes of images.

While I was addressing this patch I also had to fix a folder naming issue with the helper, which bubli was so kind to approve and also a fix in the XSLT to handle the special case of the default language, en-US.

See it at work: https://help.libreoffice.org/6.1/en-US/text/smath/01/05030000.html?&DbPAR=MATH&System=UNIX