This is a problem I’ve had for quite some time, affecting multiple versions of digiKam (4.1.0 - 5.7.0) and openSUSE (13.1 - 42.3 & TW).
Existing users, and new test user are affected alike, changing theme/widget style does not make any difference.
I reported a bug https://bugs.kde.org/show_bug.cgi?id=337243 back in July 2014 which was closed as “WORKSFORME” with the suggestion it was a distribution specific problem. I had at that stage intended to report a bug against openSUSE, but didn’t actually get around to it.
However I now need to try to address this issue.
digiKam also has the option to change font family and size for “Icon View” and “Tree View”, that works as intended.
However when attempting to change digiKam’s Tool-Tip text, font family changes as expected, font size does not. This is not restricted to any particular font, it appears to be any.
When setting the Tool-Tip font size, ( Settings -> Configure digiKam -> Tool-Tip -> Tool-Tips Font -> Custom Font -> Choose ), the text label of the “Custom Font” button correctly shows a preview of the font family at the correctly set size. In the actual Tool-Tips however, font size remains unchanged.
As this has failed across multiple users, themes, and digiKam & OS versions it rather points to a digiKam bug, I thought. However from the bug report it is clear this does work, although not for me…
I’d be appreciative of conformation or otherwise of this, and any suggestions as to solving the problem.
Actually, reading the original bug report again, specifically comment #3 ( https://bugs.kde.org/show_bug.cgi?id=337243#c3 ), I believe that Gilles’ was thinking the problem was font family, not size; perhaps I didn’t make it too clear.
I’ve added further comment to that report, but whether it will be fixed or not will, perhaps, depend upon the amount of coding needed.
Well, I had a quick look myself (I downloaded the 122 MiB source code archive a few days ago anyway to update the openSUSE package to 5.8.0).
The font size is indeed hardcoded (to “-1”) in the embedded html code.
But I think it should be possible to explicitly specify the configured font size (and maybe use “-1” as default), like it is done with the font family already.
Needs some rework though of course, I’m not sure how much work it would be.
I don’t know whether it’s a regression (but you wrote that it happens since 4.1.0, I tried 4.14.0 and that does have this problem as well), but the current code uses the HTML <font> tag to specify the font (family, size and color), which only allows to choose from a fixed number of font sizes (and the browser decides how big they really are).
This would need to be changed to use CSS “font-size” specifications instead, that allow to specify the exact size.
I.e. the embedded HTML code would need to be reworked.
But that’s basically been said in your bug report anyway.
I see it has been done already, I’ll add the patch to our package… (will take a few days until it reaches Tumbleweed of course)