Re: cairo_font_face_t not freeing
Lawrence D'Oliveiro <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Organization | Geek Central |
| Message-ID | <[email protected]> |
On Tue, 2 May 2017 14:18:10 -0400, Louis M wrote: > I understand that. But this is not my question. What I want to know is > why, after I free the context, the surface and the font_face, there is > still have a reference to the font_face. Hmmm ... it seems to have something to do with the get_scaled_font call. When I stick extra prints of the font_face refcount around there, it goes up by another 1 after the call. That is, after font_face_create, the refcount is 1; after set_font_face into the context, it is 2; then after get_scaled_font, it is 3. Then after destroying the context, it is back to 2 again. The doc <https://www.cairographics.org/manual/cairo-text.html#cairo-set-scaled-font> says the returned reference is owned by Cairo. But if I duplicate the get_scaled_font call, it does not add another 1 to the refcount. So it looks like the reference is only being created on the first call. Interestingly, all this still happens if you comment out the set_font_face call--that is, the get_scaled_font call still manages to increment the refcount of the font_face by 1, even though you never set it as the font face in the context! In this situation, the refcount goes up to 2 after the set_font_size call. However, this is only if you leave the font name as the empty string in the toy_font_face_create call. If you specify some other font (e.g. “dejavu serif” is a common one on Linux systems), then don’t call set_font_face, then the refcount stays at 1 all the way up to the dispose. But again, once you set_font_face, then get_scaled_font, the refcount gets as high as 3 as before. In other words, the toy_font_face_create call with an empty name is returning another reference to the default font that Cairo would use if you don’t specify a font. My guess is, that extra reference is coming from Cairo’s internal font-caching machinery. So presumably Cairo knows to clean it up properly when you call font_face_destroy... -- cairo mailing list [email protected] https://lists.cairographics.org/mailman/listinfo/cairo