#1715 TkAqua Scrollbar problem

[Anonymous]

The scrollbar in TKAqua does not behave as expected and is almost
unusable. --> See main window of widget demo.

The scrollbar behaviour has gotten worse from release to release.

In 8.4.5 the mouse pointer movement was almost in sync with the
scrollbar. Only off by the size of the elevator.

in other words: to scroll through the entire document the mouse
should move a distance equal to the length of the trough MINUS
the length of the elevator. apart from that 8.4.5 was fine.

in 8.4.6 it seems that the scrolbar moves twice as quickly as the
mouse pointer.

in 8.5a1 i cannot see the relationship.

to fix the bug, 8.4.5 would probably be the best starting-point.

kind regards,
uwe

uwe.kirschner@gmx.net

[Vince Darley]

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I believe this all works well in 8.5 cvs head. Can you
explain in much more detail *exactly* what the problem is
that you observe in the latest version?

Note: I do know of one relatively minor issue (unreported as
yet) which occurs when you scroll a window to one extreme
but then keep moving the mouse beyond that to the edge of
the window, but that's not a show-stopper.

[Nobody/Anonymous]

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hi vincent,
i cannot build AquaTk from CVS. my bug report is based on the 8.5a2
included in Daniel Steffen's current BI distribution.

i ran the widget demo an found that the scrollbar of the main window
doesn't follow the mouse pointer:

- open the widget demo

- pick the slider of the main window scrollbar

- move down slowly

- after a few millimeters the slider jumps to the bottom of the scrollbar

- try to move the slider back up

- the slider will follow the mouse a short distance and then jump back to
the bottom of the scrollbar.

- while moving the slider up (before it jumps back down) it is not in sync
with the mouse pointer. it moves upward more quickly than the mouse
pointer. its seems that it jumps back down exactly at the point when the
rounded bottom end of the slider is at the same hight as the mouse
pointer

- resize the window (enlarge) so much that the slider covers morst of the
scrollbar. the slider will now work properly.

- resize the window again (smaller) so that the slider will cover only a
small portion of the scrollbar. the slider will get screwy again and not
follow the mouse pointer properly.

- move the mouse up and down a few times while keeping the button
pressed down. the slider will get more and more out of sync with the
mouse pointer.

- the amount the slider is out of sync seems somehow related to the
fraction of the scrollbar that it covers.

i hope that helps. perhaps this is already fixed in the cvs head version.

kind regards, uwe

uwe.kirschner@gmx.net

[Joe English]

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The behavior described below isn't Aqua-specific -- the same
thing happens on X11 and Windows when running the widget demo.

I suspect this is related to recent changes to the text
widget (TIP #155 implementation), not the scrollbar.

[Vince Darley]

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Ok, I can reproduce the issue, more or less. It appears to
be a problem where the text widget decides all pixel-height
calculations are up to date, when they're not.

A simple '.t configure -bd 0' will force all calculations to
repeat and then the scrollbar is the right height.

I'll have to look into it.

[Vince Darley]

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Ok, fixed at last!

Turned out to be a very subtle problem in which the text
widget's record of the partial height calculation for a very
long wrapped line was being incorrectly re-used.