NSTableView Highlighting, Speed, etc.
NSTableView Highlighting, Speed, etc.
- Subject: NSTableView Highlighting, Speed, etc.
- From: Keith Renz <email@hidden>
- Date: Fri, 17 Jan 2003 19:28:47 -0500
I have a table view (n rows x 2 columns), which doesn't lend itself to
text, so I am drawing each cell with a custom graphic (NSImage). I have
several questions...
1) I am filling the entire row with an NSImage, which apparently blocks
the table views highlighting. I would still like to use NSTableView's
highlighting, so what should I do? I either have to make the image
smaller or make parts of it transparent. Is there some way to apply the
highlighting on top of the image?
2) This particular table view will generally have several hundred rows,
with a maximum of around 2,000 rows. The cell sizes are 38 x 23 (width
x height) for the 1st column and 805 x 23 for the 2nd column. I was
initially allocating a new NSImage for each cell and releasing it after
passing it off to the table view. I then switched to 2 reusable
NSImages, but I did not notice any appreciable difference in
performance. With allocating images, I didn't have to erase a reusable
image, so maybe it's a wash. Any thoughts on what might be better here?
3) With my table view (and others I've tried), It appears that the
vertical scroll bar's "thumb" has some sort of throttling mechanism. If
I move the thumb slowly, the table view keeps up with it nicely. As I
move it faster, there seems to be a distinct point where it gets jerky
and the table no longer smoothly keeps up with the movement. If I use
the scroll bar's arrows, it scrolls very fast, significantly faster
than it does by moving the thumb. Why does it seem like the thumb's
fastest smooth rate is slower than the up/down arrow's?
(PowerBook G4, Mac OS X 10.2.3, Dec 2002 Dev Tools)
Thanks,
Keith
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