fix issues #74 and #100 : trailing space crash

[jamma313]

If available width is known and equals to 0, we don't have space to write to, so return.

[SimonSapin]

I’m not confident with this part of the code. @liZe , could you review?

[liZe]

The second commit is OK (yes, that's a 'bad' cutting value from pango, and your solution is a not-so-bad workaround). But the first commit is false and should not be merged. Having no available space is not a sufficient reason to skip text, we must draw it even if it goes outside the box, it will be clipped if overflow is set to hidden. You can try with the example given in #74, the text must be visible.

By the way, this commit fixes #74 but not #100 for me. Did I miss something?

[jamma313]

Yes you're right.
First commit was wrong, and sometimes truncated text.
I saw this a little bit after doing the pull request, but still was testing it.

#100 was fixed by first commit, so it is still bugged.

[liZe]

I've merged your second commit, thanks!