64504 - Layout is unable to handle X_DPI != Y_DPI

Status: NEW

(Core :: Layout, defect)

Description

[robbe]

There's no way to tell Mozilla that my display resolution is, for example,
100x75 dpi. The Preferences only allow one to enter one value for dpi.
Likeliwise, when the dpi is fetched from the X server, the y value is ignored.

This may not be too relevant for fonts, but having the dpi right is essential
for CSS lengths (see attached testcase).

Most modern displays will have dpis that vary only by a few dots from x to y,
but old and/or exotic devices may have dpis differing by a factor of two.

To reproduce:
* Configure X server for odd dpi values (e.g. for XF4, stick "DisplaySize 400
150" in the "Monitor" section of the config file)
* Check with xdpyinfo
* Be sure to set Mozilla's dpi override to 0 (so that the values will come from
the X)
* Varying the y dpi value should influence the top/bottom border in the testcase.

Comment 1

[robbe]

Attachment: testcase

Comment 2

[Hixie (not reading bugmail)]

Pav: potential idea for GFX2 

Comment 3

[buster]

unlikely to tackle this any time soon

Comment 4

[Kevin McCluskey (gone)]

Build reassigning Buster's bugs to Marc.

Comment 5

[Christopher Hoess (gone)]

*** Bug 141686 has been marked as a duplicate of this bug. ***

Comment 6

[Roland Mainz]

Note that this issue affects printing, too.

Comment 7

[Christopher Aillon (sabbatical, not receiving bugmail)]

.