804486 - horizontal scrolling amount is too small

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Timothy Nikkel (:tnikkel)]

Horizontal scrolling is far too slow. I think we scroll 10 pixels per key press or scrollbar arrow button click.

Comment 1

[Mats Palmgren (inactive)]

Attachment: fix

Our horizontal "line" scroll is currently hard-coded to 10px.
This patch changes it to 5 * AveCharWidth() for the scroll frame's font,
where the 5 can be changed with the pref
"toolkit.scrollbox.horizontalScrollDistance".

I've tested this on Linux at various fonts/sizes, and as far as I can tell
this is identical to what Chrome does.  Opera is also close but generally
scrolls slightly less.

Comment 2

[Mats Palmgren (inactive)]

Attachment: s/fontHeight/increment/ to make some code less confusing

Comment 3

[Mats Palmgren (inactive)]

Attachment: fix tests

Adjusting some tests that makes wrong assumptions about horizontal
line scroll distance.

All tests now pass:
https://tbpl.mozilla.org/?tree=Try&rev=3d841c269a9a

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Comment on attachment 675998 [details] [diff] [review]
fix

Review of attachment 675998 [details] [diff] [review]:
-----------------------------------------------------------------

::: modules/libpref/src/init/all.js
@@ +343,5 @@
>  pref("toolkit.scrollbox.smoothScroll", true);
>  pref("toolkit.scrollbox.scrollIncrement", 20);
>  // Make sure to update NS_DEFAULT_VERTICAL_SCROLL_DISTANCE if changing this default.
>  pref("toolkit.scrollbox.verticalScrollDistance", 3);
> +// Make sure to update NS_DEFAULT_HORIZONTAL_SCROLL_DISTANCE if changing this default.

Why? I don't think it matters if NS_DEFAULT_HORIZONTAL_SCROLL_DISTANCE is not updated.

Comment 5

[Mats Palmgren (inactive)]

(In reply to Robert O'Callahan (:roc) (Mozilla Corporation) from comment #4)
> Why? I don't think it matters if NS_DEFAULT_HORIZONTAL_SCROLL_DISTANCE is
> not updated.

True, but I think it's merely documenting the existence of that symbol
so that it can be found easily.  Should I remove both comments in the
prefs file then?  And do we really need the symbols?  (there's no other use
of these symbols other than the fallback arg to Preferences::GetInt)

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I think you can just remove the comments. There's no need to keep the all.js default in sync with the no-pref-at-all default.

Other than that, you might as well just leave the symbols as-is.

Comment 7

[Mats Palmgren (inactive)]

Ok, removed the comments only.

https://hg.mozilla.org/integration/mozilla-inbound/rev/49fdae25aac9
https://hg.mozilla.org/integration/mozilla-inbound/rev/1212408eac29
https://hg.mozilla.org/integration/mozilla-inbound/rev/a886c22fe9d1

Comment 8

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/49fdae25aac9
https://hg.mozilla.org/mozilla-central/rev/1212408eac29
https://hg.mozilla.org/mozilla-central/rev/a886c22fe9d1