Fixes#2674.
The cause of the issue was in get_pango_layout. When we call
pango_parse_markup, `text` is the escaped string, and the unescaped
string is then computed and written to `buf`. We were then passing the
unescaped string to pango_layout_set_markup, but this function needs the
escaped string. `buf` is not needed and has been removed.
The other part of this PR refactors escape_markup_text to remove the
dest_length argument and removes the -1 return value on error. It now
assumes that you've allocated dest to the correct length.
This does the following:
* Adds a baseline argument to get_text_size (the baseline is the
distance from the top of the texture to the baseline).
* Stores the baseline in the container when calculating the title
height.
* Takes the baseline into account when calculating the config's max font
height.
* When rendering, pads the textures according to the baseline so they
line up.
The condition checking if the markup is valid was inverted.
This commit also adds better error handling: if the markup cannot
be parsed, it fallbacks to plain text.
This starts up the event loop and wayland display and shims out the
basic top level rendering concepts. Also includes some changes to
incorporate pango into the 1.x codebase properly.
