In my last post discussing changes in Pango 1.44, I’ve asked for feedback. We’ve received some, thanks to everybody who reported issues!
We tried to address some of the fallout in several follow-up releases. I’ll do a 1.44.4 release with the last round of fixes before too long.
Here is a summary.
As expected, not supporting Type 1 and BDF fonts anymore is an unwelcome change for people whose favorite fonts are in these formats.
Clearly, a robust conversion script would be a very good thing to have; people have had mixed success with fontforge-based scripts (see this issue). I hope that we can get some help from the font packager community with this.
One follow-up fix that we did here is to make sure that Pango’s font enumeration code does not return fonts in formats that we don’t support. This makes font fallback work to replace bitmap fonts, and helps to avoid ‘black box’ output.
Font rendering is a sensitive topic; every change here is likely to upset some people (in particular those with carefully tuned font setups).
We did not help things by enabling subpixel positioning unconditionally in Pango, when it is only supported in cairo master. When used with the released cairo, this leads to unpleasantly uneven glyph placement. Even with cairo master, some compositors have not been updated to support subpixel positioning (e.g. win32, xcb).
To address this problem, subpixel positioning is now optional, and off by default. Use
pango_context_set_round_glyph_positions (context, FALSE)
to turn it on.
Even without subpixel positioning, there is are still small differences in glyph positioning between Pango 1.43 and 1.44. These are caused by differences in glyph extent calculations between cairo and harfbuzz; see this issue for the ongoing discussion.
I was a bit overzealous in my attempt to reduce our dependency on freetype when I changed the return type of pango_fc_font_lock_face() to gpointer. This is a harmless change for the C API, but it broke some users of Pango in C++. The next release will have the old return type back.
Another new feature that turned out to be better of being off by default is the new line spacing. In the initial 1.44 release, it was on by default, causing line spacing UIs (e.g. in the GIMP) to stop working, which is not acceptable. It is now off by default. Call
pango_layout_set_line_spacing (layout, factor)
to enable it.
We’ve received one bug report pointing out that hyphens could be confusing in some contexts, for example when breaking filenames. As a consequence, there is now a text attribute to suppress the insertion of hyphens.
Naturally, some bugs crept in; there were some crash fixes, and some hyphens got inserted in the wrong place (such as: hyphens after hyphens, or hyphens after spaces). These were easy.
One bug that took me a while to track down was making lines grow higher when they are ellipsized, causing misrendering. It turned out to be a mixup with text attributes, that let us to pick the wrong font for the ellipsis character. This will be fixed in the next release.