gtk_font_chooser_set_font_map ?

Yep.  With getter please.

Created attachment 302908 [details] [review]
GtkFontChooser: Allow a custom font map

This lets applications show their own fonts instead of
or in addition to system fonts.

Quick implementation.

To test, use e.g

 ./testfontchooser ~/.fonts/Hind-Medium.ttf ~/.fonts/Hind-Bold.ttf 

to get a font chooser which has just Hind Medium, Hind Bold, and the standard aliases (monospace, sans, serif).

Note that I had to define PANGO_ENABLE_BACKEND and include pangofc-fontmap.h in testfontchooser.c - is that intentional ?

Definitely not intentional.  I'll check as soon as I can build gtk+.  Thanks!

Review of attachment 302908 [details] [review]:

::: tests/testfontchooser.c
@@ -68,0 +71,11 @@
+  if (argc > 1)
+    {
+      FcConfig *config;
... 8 more ...

Use pango_cairo_font_map_new_for_font_type(CAIRO_FONT_TYPE_FT).  If cairo-ft is not available, skip this part of the test.

Created attachment 302917 [details] [review]
GtkFontChooser: Allow a custom font map

This lets applications show their own fonts instead of
or in addition to system fonts.

Better patch - use that cairo_font_map api - no longer need the backend define now, yay. Also made GtkFontButton work, and added the same test code to testfontchooserdialog.

I was idly wondering if apps can actually use this already, do they have to do anything to the font maps of their widgets to use fonts returned by such a font chooser ? I guess since we mostely deal with fonts in an 'unresolved' (textual) form, we do need a way to tell other widgets which font map to use to resolve them. That opens up an interesting question about inheritance of pango contexts / font maps.

To point that out, the example I gave with Hind happens to work because the font I'm 'adding' to the font map is in the reguar fontconfig paths anyway. If I had used an entirely custom font, things probably won't work...

Humm.  Yes, I think it's desirable to be able to attach a fontmap to a widget too.  Right now, what I had in mind, was that apps like GIMP or Inkscape use this with direct cairo / pango calls.

This builds, but the test doesn't work for me.  Didn't get to debug.  Does it work for you?

It worked to the extent described in comment 4: I got a font chooser which had just Hind, sans, serif, and monospace in it.

I suppose it worked before ebassi's changes.  Does after, since fonts are loaded once, then fontmap set, and not loaded again.

Currently the widget loads fonts in _init().  If I remove that then it "works".  Ideally I want to avoid loading in _init() in case user wants to set the config.

I suggest removing it from _init().  It's already called from style_updated.  And then add a variant that forces loading, perhaps by clearing last_fontconfig_timestamp first.

Also, the problem with saving the font_map in the widget's PangoContext is that it's lost if the screen changes.  So we either have to save it somewhere else, or change gtkwidget to preserve it.

I wonder if saving this in the gtkwidget is even a good idea.  Apparently doing so does not change the fontmap use for rendering the dialog itself.  I suppose because it's not inherited into the components that draw the dialog.  Right?

I think asking users to call pango_context_set_font_map() on the context returned by gtk_widget_get_pango_context() is legit, if we make gtkwidget preserve that forward across screen change.

Thanks!

Created attachment 303004 [details] [review]
GtkFontChooser: Allow a custom font map

This lets applications show their own fonts instead of
or in addition to system fonts.

lgtm.  Tested and it works.  Thanks!

One issue: instead of FcConfigCreate(), use FcInitLoadConfig().  This way synthetic bold and italic also work.

And since this probably will end up being a demo of how to do this, perhaps add a comment with FcInitLoadConfigAndFonts() as well.  That version will keep the system fonts.

Or just push this, and I'll add add comments and push.

I think I'll add a commented 'custom font chooser' example in the 'pickers' example in gtk3-demo.

Attachment 303004 [details] pushed as 049cbc8 - GtkFontChooser: Allow a custom font map

Created attachment 303062 [details] [review]
Fix precondition in gtk_font_chooser_get_font_map ()

We need to return a value here.

For reference, I discussed using custom fonts with pango+fontconfig in detail here:
http://mces.blogspot.ca/2015/05/how-to-use-custom-application-fonts.html