233082 - default value of browser.display.screen_resolution is wrong

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

The default value of the browser.display.screen_resolution is wrong.  It was
supposed to be -1 (meaning max(96dpi, system setting)), but it somehow got set
to 0 (meaning system setting).  This can make pages with point-specified font
sizes unreadable on systems with a system setting considerably under 96dpi
(e.g., 75dpi).

Gerv broke this in his patch for bug 81904.

I think the prefs dialog should have a name for -1 -- I'm tempted to use "Best".

Comment 1

[Hixie (not reading bugmail)]

"Optimal"?

Comment 2

[Felix Miata]

"meaning max(96dpi, system setting)"

What is it supposed to be when the system setting is in fact greater than 96?
Either? Greater of? Smaller of?

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

max() is a common notation for a function that returns the larger of its two
arguments.  I meant, use the system's idea of DPI if larger than 96dpi,
otherwise use 96dpi.  This prevents fonts specified in pt from being too small.

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: patch

This doesn't matter as much these days, since Xft's default is 96 instead of the old X 75, but we still don't want to use less than 96 for people who configure Xft that way (Fedora has UI for it), since it makes some Web pages illegibly small.

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Checked in to trunk.

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Checked in to MOZILLA_1_8_BRANCH.