Discussion in bug 1171568 and bug 1214470. Icons in the UI will scale, which is not desired. That's related to 412073.

The only change in behaviour introduced here is that dpi values in the range [144,168) will now use pixel scaling of 1.5 instead of 2. Review commit: https://reviewboard.mozilla.org/r/51883/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/51883/

(In reply to Karl Tomlinson (ni?:karlt) from comment #0) > Icons in the UI will scale, which is not desired. That's related to 412073. Well, they are already scaling. And this patch will make them scale less.

Comment on attachment 8751139 [details] MozReview Request: bug 1271893 add a 1.5 pixel-scaling step r?acomminos https://reviewboard.mozilla.org/r/51883/#review48753

Are you sure this is better? It looks way smaller than the other GNOME applications to me. Firefox makes me want to increase DPI, but if I increase it it's too much for the other applications.

The dimensions of my display are 2880x1620.

And I've set my scaling factor to 1.62 (now to 1.75 to overcome this annoyance). Could we approximate to 1.5 when the scaling factor is less than 1.5 and approximate to 2 when the scaling factor is > 1.5?

This is the reference rendering. There are plenty of imperfections, but the scaling at other dpi should attempt to be consistent with this. dpi scaling shouldn't try to correct imperfections in the reference rendering. Firefox text entries are too small in the urlbar and too large in the Library window. The main toolbars are a similar size, except for the Library window, which is affected by the huge back/forward icons, I assume. The lineheight in the tree view and history list is smaller than in the Character Map script list. Firefox is failing to draw the buttons on the dropdown menus except during hover, but the "show all tags" button is visible. The dropdown button icons are incorrect.

Text entries are all too large, even in urlbar. Main toolbar is larger than Character Map toolbar. Menubar too large. Lineheight too large. All icons are too large.

This seems more consistent with the 96 dpi and unit scale situation to me. Do you have counterexamples?

The Firefox UI looks almost OK, but the text in web content becomes really small.

Wrong image...

Comment on attachment 8753393 [details] screenshot.png "some text" here looks like it is a monospace font. I don't know what is causing it to be rendered with monospace, but the default size for monospace is different from proportional. That's probably a legacy decision and so should change. Bug 328621 has a good testcase or compare these: data:text/html,some text data:text/html,<pre>some text

The text looks too small to me, but maybe it's just me, I don't know.

It looks like we have different GTK font sizes. GTK defaults to 10 pt, which is the size on the right with DejaVu Sans at 155.52 dpi. If attachment 8753762 [details] (left) was at 1.62 font scale, then it looks like 11 pt, but perhaps the difference comes from a different font. Is it possible you or the distribution have changed the GTK font size to 11 pt?

I think 11 is the default on Ubuntu.

The font-size in recorded bugzilla comments is 13px in the default theme. That's 9.75pt, so it is expected to be smaller than an 11pt system font.