175380 - PageDown/PageUp leave too much in common between "pages"

Status: RESOLVED FIXED

(Core :: Web Painting, defect, P1)

Description

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

This has been annoying me for years (I mean it), and I'm finally filing a bug
about it, which I've been meaning to do for years.

I use Mozilla at a default font size and window size that allows me over 50
lines of text in a window.  PageUp and PageDown cause Mozilla to scroll by 90%
of the window size.  This means there are about 5 lines of text that are present
on the screen both before and after the PageUp/PageDown.  This has often made it
hard for me to find my place when I move up and down.

The simple solution to this, is, I think, to bound the scroll amount in
nsScrollPortView::ScrollByPages so that it is never less than one page minus two
or three lines at the default font size.  I'd like to do this, but I'm
interested in other people's opinions on the topic.  I'll probably post to
n.p.m.ui at some point about this...

(I realize there are much nicer solutions such as showing and hiding a box where
the previous position on the page was or temporarily opaquely-greying out the
part that was already seen, but they're harder.  This is a trivial patch.)

Any other opinions on this?

Comment 1

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

Attachment: patch

The changes to nsSelection.cpp are wrong, and perhaps even uunecessary.

Comment 2

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

Attachment: patch

This is updated to the trunk, and doesn't break PgUp/PgDn when the scroll view
is at the start/end but the caret isn't yet (which the previous patch did, I
think).

Comment 3

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

Fix checked in to trunk, 2004-10-24 14:05 -0700.