When line spacing is non-zero, the empty line height doesn't match the height of a regular line
It looks like line spacing is not taken into account when the height of an empty line is calculated.
Download the Test.txt and the Test1.txt files. Then run pango-view Test.txt --line-spacing=1.0 & pango-view Test1.txt --line-spacing=1.0
. Comparison of the results will look like this:
This behavior is reproduced in pango 1.48.5.