852522 - system font sizes are not scaled in response to dpi

Status: RESOLVED FIXED

(Core :: Widget: Win32, defect)

Description

[Jonathan Kew [:jfkthame]]

Attachment: scale system font sizes in response to dpi/devPixelsPerPx setting

As described in bug 844604 comments 17 and 19, we're not scaling the "system" font sizes on Windows (as used for various chrome elements) in response to changes in the devPixelsPerPx value (whether set explicitly or using the new default of -1 = auto).

It's easiest to see this by opening about:config and changing devPixelsPerPx to values such as 0.5, 2, and 3; note that although the UI in general scales in response, the font sizes in the tab header, location bar, bookmarks bar, etc do -not- scale.

Comment 1

[Jim Mathies [:jimm]]

Comment on attachment 726647 [details] [diff] [review]
scale system font sizes in response to dpi/devPixelsPerPx setting

Thanks for working on cleaning these issues up.

Comment 2

[Jonathan Kew [:jfkthame]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/b55cc3437395

Comment 3

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/b55cc3437395

Comment 4

[Gary [:streetwolf52]]

Seems that with this patch setting devPixelsPerPx to 1.0 the 'system' fonts are small probably 96dpi even though I have an OS dpi of 120.

Comment 5

[Gary [:streetwolf52]]

Filed https://bugzilla.mozilla.org/show_bug.cgi?id=852963

Comment 6

[Jonathan Kew [:jfkthame]]

(In reply to Gary [:streetwolf] from comment #4)
> Seems that with this patch setting devPixelsPerPx to 1.0 the 'system' fonts
> are small probably 96dpi even though I have an OS dpi of 120.

Yes indeed. Because if you set devPixelsPerPx to 1.0, you're telling Firefox you want to *override* the system dpi setting and treat your display as though it were 96dpi. So you get smaller fonts.