327826 - Font size logic is reversed

Status: RESOLVED WONTFIX

(Firefox :: General, defect)

Description

[Erik Hensema]

When a font size is given in pt, its size on screen should be independent of the resolution of the screen, given the system knows the correct dpi setting of the monitor.
So, the lower the dpi, the less pixels per inch, so in a constant point size, the size in pixels of a font should decrease.
In other worlds: pixel size of fonts is proportional to the dpi setting.

In firefox this is reversed.

Firefox correctly calculates the size of dialogs correctly. So, when running in a low dpi setting, dialogs get smaller because the fonts in them should get smaller. But they don't. They get larger.

I'll attach some screenshots of firefox in various dpi settings to illustrate the problem.

Operating environment:

Suse Linux 10.0
Firefox 1.5.0.1, from suse rpms

Comment 1

[Erik Hensema]

Attachment: main window, 112dpi (system setting)

Comment 2

[Erik Hensema]

Attachment: Prefs, 112dpi

Comment 3

[Erik Hensema]

Attachment: Main window, 64 dpi

Comment 4

[Erik Hensema]

Attachment: Prefs, 64 dpi. Observe the window is way too small now.

Comment 5

[Erik Hensema]

Attachment: main window, 150dpi

Comment 6

[Erik Hensema]

Attachment: prefs, 150dpi. Window is way too big now.

Comment 7

[Erik Hensema]

This buggy font handling was introduced in firefox 1.5. 1.0.x was fine.

Comment 8

[:Gavin Sharp [email: [e-mail]]]

Could you try recent nightly trunk builds (ftp://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk) and see if the bug is still present? There were some fixes that might be related to this.

Comment 9

[Felix Miata]

Does your profile directory contain a chrome directory? If so, is there a userChrome.css file there? If so, what does it contain?

What method are you using to change your DPI?

With SuSE 10.0 in minefield 20060525 this is worksforme as follows:

DPI     pref window size
84      499pxX432px
96      569pxX491px
108     639pxX551px
120     709pxX611px

Comment 10

[Erik Hensema]

bug is filed against ff 1.5 -> closing