[Sugar-devel] Scrollbar width

Albert Cahalan acahalan at gmail.com
Fri Dec 11 03:02:38 EST 2009

It's perfectly reasonable to have a scroll bar that isn't anywhere
near the edge of the screen. (scrolling a list, etc.) We must not
forget this when discussing things like "infinite target width".

That said, at least for the common case of the scrollbar being at
the edge of the screen and possibly elsewhere, there is a solution.
Scrollbars could widen up as the mouse goes over them, overlapping
into/above the area that is to be scrolled.

It's a nice solution, allowing for scrollbars 100 pixels wide.

Speed is critical of course. Being slow like the Frame would be
some kind of torture. My best guess for appropriate timing:

a. movement begins in less than 30 ms
b. movement is done in less than 200 ms (no exceptions ever)

In that time there ought to be 6 to 12 frames drawn. Drop frames
as required to meet the required performance.

I'm thinking the speed ought to vary, like this:

0 ms, 8 pixels (begin state)
20 ms, 12 pixels
40 ms, 16 pixels
60 ms, 24 pixels
80 ms, 40 pixels
100 ms, 72 pixels
120 ms, 88 pixels
140 ms, 96 pixels
160 ms, 100 pixels (end state)

Motion blur would help. (precomputed I suppose)

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