Re: NSImageView does not update on setNeedsDisplay
Re: NSImageView does not update on setNeedsDisplay
- Subject: Re: NSImageView does not update on setNeedsDisplay
- From: Eric Smith <email@hidden>
- Date: Fri, 18 Nov 2005 07:23:38 -0800
Hi Dan. Thanks for the reply.
I actually do call [theImage setCacheMode:NSImageCacheNever],
although it doesn't help in this situation. It DOES help me in
another way, however. I have two views, each displaying the same
NSImage. I had to specify NSImageCacheNever in order for the <ugly>
[theCell setImage:nil]</ugly> (as it was described by another list
user) to work on both images. That is, if the image were cached, it
would be updated in only one view.
I do not implement a drawRect function... just goes straight to the
super class.
If I don't use the ugly business, the view will update the image if
it is resized (this was similar to another posting I saw in the
archive, but there were no replies). Seems to indicate that one or
two appropriate messages to the appropriate class will cause the view
to update... I just can't figure out what they are!
Thanks again,
Eric
On Nov 17, 2005, at 11:33 PM, Daniel Waylonis wrote:
On Nov 17, 2005, at 8:24 PM, Eric Smith wrote:
I've downloaded several Apple code samples, wherein an
NSImageView's image is changed. After the image is changed, a
simple call to [imageView setNeedsDisplay:YES] is sufficient to
update the image in a GUI. However, when I do this in my code,
the image is not updated in the GUI.
I'm changing the bitmap data. When I change the data, I have to
get the NSImageView's cell, and do [viewCell setImage:nil]. Then
I can do a [viewCell setImage:theImage], and the image will be
updated in the GUI. What am I doing wrong? What needs to be done
in order for an NSImageView's image to be updated in a GUI?
Hi Eric,
Quite often, NSImage will create a cached representation of your
bitmap for display purposes. If you're just changing the bitmap
under the covers, the NSImage doesn't know that things have changed.
You can specify:
[theImage setCacheMode:NSImageCacheNever];
and it should always use your bitmap for drawing.
Dan
-----------------------------------------------------------------
Dan Waylonis email@hidden
nekotech SOFTWARE
http://www.nekotech.com
650.964.2490 Voice / Fax
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