Re: IKImageBrowserView image quality changing with redraw
Re: IKImageBrowserView image quality changing with redraw
- Subject: Re: IKImageBrowserView image quality changing with redraw
- From: Adam Berger <email@hidden>
- Date: Tue, 8 Dec 2009 10:50:30 -0800
This has so far only been tested on SnowLeopard.
I'm going to divide this into two issues, since I'm not 100% sure they're
related.
1) On redraw, a filtering is applied that changes the image quality. Are you
seeing this change on first redraw from a large NSImage (rather than from a
url to an image)?
2) The filtering applied may actually be appropriate for photographs, but
I'm dealing with line drawings, which become completely unusable when scaled
in this way. Even zero antialiasing would be greatly preferred
3) (Not an issue, but a possible solution that didn't work.) If providing an
NSImage with multiple NSImageReps that only vary in resolution, icon style,
IKImageBrowserView seems to always work with the first/largest. If I could
make this work, I'd just generate multiple thumbnails. (I suppose I could
throw away all thumbnails on bump the version number on scale change...
expensive, though.)
I've put up three screenshots:
• http://www.addaon.com/IKImageBrowserView_scaling_A.png
is a manually-scaled high-quality image (about half the size of the
original; just for comparison)
• http://www.addaon.com/IKImageBrowserView_scaling_B.png
is how it appears initially (before redraw); this is marginally acceptable
• http://www.addaon.com/IKImageBrowserView_scaling_C.png
is the over-filtered form
Again, the transition between B and C happens whenever I cause a redraw, for
example by clicking on the background.
Hard to overstate this problem.
Adam
On Tue, Dec 8, 2009 at 5:59 AM, Thomas Goossens <email@hidden> wrote:
> Hi Adam,
>
> Is this on Leopard or Snowleopard ?
> I just tried to load images from /System/Library/Desktop Pictures in an
> IKImageBrowserView using the NSImage representation. They appears just fine
> for me (SnowLeopard).
>
> > I'm trying to move from a custom view to an IKImageBrowserView in a
> project,
> > and running into a somewhat odd problem. Context: my IKImageBrowserItems
> are
> > IKImageBrowserNSImageRepresentationType, backed by a relatively
> > large (~600x800) NSImage.
> >
> > When first drawn, at any scale factor, this looks great. However, as soon
> as
> > a redraw (not a reload!) occurs, the quality goes to hell. For example,
> > clicking in the browserview will cause this problem instantly. It's as if
> > it's deciding all of a sudden to fall back to a cached image of much
> lower
> > quality. Scrolling seems not to trigger a redraw of this type; so if a
> large
> > view containing as-first-drawn high quality images is clicked, only the
> > currently visible thumbnails will get degraded, and scrolling can then
> > present a mix of degraded and full-quality images.
> >
> > Needless to say, this huge a reduction in image quality is not
> acceptable.
> > How can this be prevented?
>
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