Pixelation on hi-res zoom in x64 Windows

[daveful]

With certain high resolution images zooming to 100% does not work correctly:

- sometimes the image remains very blocky with huge pixels and never zooms correctly
- sometime the image zooms but the fine detail is pixelated
- sometimes it works correctly

Here's a link to a set of demo images made with the new Leica S2.  Download the full-resolution versions of some of these and the problem should become apparent.

http://www.dpreview.com/news/0911/09111203leicas2gallery.asp

This is happening under x64 Windows 7 Ultimate.  It also happened under Vista Ultimate.  It does not happen in the Mac version.  I'm running version 4.6.2 of Photo Mechanic.

Attached is a screen capture that illustrates the problem (it's the first kind of problem listed above).

 

[attachment deleted by admin]

[Kirk Baker]

With certain high resolution images zooming to 100% does not work correctly:

- sometimes the image remains very blocky with huge pixels and never zooms correctly
- sometime the image zooms but the fine detail is pixelated
- sometimes it works correctly

Here's a link to a set of demo images made with the new Leica S2.  Download the full-resolution versions of some of these and the problem should become apparent.

http://www.dpreview.com/news/0911/09111203leicas2gallery.asp

This is happening under x64 Windows 7 Ultimate.  It also happened under Vista Ultimate.  It does not happen in the Mac version.  I'm running version 4.6.2 of Photo Mechanic.

Are you giving the preview some time to load?  I downloaded several of the images on my Windows XP system and they zoomed in at 100% just fine.  There was a several second delay however.

-Kirk

[daveful]

The problem persists no matter how long you wait.  I've waited as long as 10 minutes.  You could wait all night.

I might add, this happens whether the images are stored on a local drive or on a server.  Further, I should add that it happens when you are zoomed in to 100% and use the arrow keys to change images rapidly.  It seldom happens on the first image you view.  However, once it winds up with a "permanently pixelated" image, that particular image stays pixelated even though adjacent images may look just fine as you move to them.

I think the technical term for this kind of behavior is bug.  It doubtless is a multi-threading issue, race condition, or some-such.

[Kirk Baker]

The problem persists no matter how long you wait.  I've waited as long as 10 minutes.  You could wait all night.

I might add, this happens whether the images are stored on a local drive or on a server.  Further, I should add that it happens when you are zoomed in to 100% and use the arrow keys to change images rapidly.  It seldom happens on the first image you view.  However, once it winds up with a "permanently pixelated" image, that particular image stays pixelated even though adjacent images may look just fine as you move to them.

I think the technical term for this kind of behavior is bug.  It doubtless is a multi-threading issue, race condition, or some-such.

Our image loading code is the same on Mac OS X and Windows, and you claimed earlier that you cannot get it to happen on your Mac.  So while I completely believe you that you can get this problem to happen and I would also agree that it would be a bug, we need to be able to reproduce the problem on our end in order to fix it.

How many images do we need to rapidly move through in order to get the problem to happen?

-Kirk

[Kirk Baker]

The problem persists no matter how long you wait.  I've waited as long as 10 minutes.  You could wait all night.

I might add, this happens whether the images are stored on a local drive or on a server.  Further, I should add that it happens when you are zoomed in to 100% and use the arrow keys to change images rapidly.  It seldom happens on the first image you view.  However, once it winds up with a "permanently pixelated" image, that particular image stays pixelated even though adjacent images may look just fine as you move to them.

I think the technical term for this kind of behavior is bug.  It doubtless is a multi-threading issue, race condition, or some-such.

Would you be willing to run a logging version of Photo Mechanic so that we might find out what is going on when running on your system(s)?

Thanks,

-Kirk

[daveful]

Kirk,

I'd be delighted to run your logging version.

While it's doubtless true that you use the same display code for Mac and PC, the operating systems are certainly different and, if it's a race condition, stack overflow, or some obscure multi-threading problem, your code might run differently on the two systems.

In answer to your question about how many images you have to go through ...  it varies but usually occurs after no more than 6-12 images.  It seldom occurs with just one or two.

I am certain that the problem relates to, when zoomed to 100%, pressing the arrow key to go to the next image before it's finished drawing the current image.  If you do that enough so you've moved past a number of images which have not had time to draw in full resolution, the program gets confused.  

There's another factor.  It is definitely dependent on the image size.  The images that exhibited the worst problems were 39 megapixels images.  The ones I sent you were made by the new Leica S2.  However, I've seen the same thing with my 39 megapixel Hasselblad H3.

I'll do whatever I can to help you debug this.  I've been using Photo Mechanic for many years and want it to continue to work perfectly.

Sorry it took so long to get back to  you.  I was in meetings this afternoon.

Dave

[Kirk Baker]

Dave,

I'd be delighted to run your logging version.

While it's doubtless true that you use the same display code for Mac and PC, the operating systems are certainly different and, if it's a race condition, stack overflow, or some obscure multi-threading problem, your code might run differently on the two systems.

In answer to your question about how many images you have to go through ...  it varies but usually occurs after no more than 6-12 images.  It seldom occurs with just one or two.

I am certain that the problem relates to, when zoomed to 100%, pressing the arrow key to go to the next image before it's finished drawing the current image.  If you do that enough so you've moved past a number of images which have not had time to draw in full resolution, the program gets confused.  

There's another factor.  It is definitely dependent on the image size.  The images that exhibited the worst problems were 39 megapixels images.  The ones I sent you were made by the new Leica S2.  However, I've seen the same thing with my 39 megapixel Hasselblad H3.

I'll do whatever I can to help you debug this.  I've been using Photo Mechanic for many years and want it to continue to work perfectly.

Sorry it took so long to get back to  you.  I was in meetings this afternoon.

I'll get a logging version built today and send you a download link to it later today.

-Kirk

[Kirk Baker]

Dave,

I'd be delighted to run your logging version.

I sent you the link to the test version (check your "My Messages" button at the top of the page.)

Thanks,

-Kirk