Rev cannot open my jpeg ! - and some serious thinking

[Jerry J]

On Jun 28, 2009, at 10:07 AM, Mike Markkula wrote:

> Sarah,
>
> I too wish wish wish Rev would remove the 4095 pixel width limit!
> (there is no height limit) As is, its a deal breaker for any serious
> app in the photography arena.

I've been looking into the problem with images wider than 4091 pixels  
on OS X.

A while ago, Devin Asay suggested that one could load the image, then  
split the imagedata before displaying it in sections. Mike Markkula  
wrote a nice stack to do just that, but asked for my help when it  
didn't work quite correctly, for no apparent reason.

The problem is worse than we thought. A wide image imports without  
reporting errors, but the imagedata is messed up before you can get to  
it. Its very odd. If an image is 4091 wide, everything seems fine. If  
an image is wider than that, the imagedata is wrong starting with  
pixel #4048 (!). What a strange number!

The scary part is that the messed up bytes came from somewhere wrong.  
We don't know where they came from. Its unlikely that they would be  
outside of Rev's app space (page fault) but it could be dangerous to  
_write_ to those locations by exporting the image by whatever means.

I made an ugly little stack to view the raw pixels of an image. Its at:
http://www.jhj.com/WideBug.zip
  with some test images that have consistent RGB values. Note that  
pixel 4047 is OK, 4048 is not. 4100 (last of first row) is not, and  
different. In each example, the last row appears to be correct. I  
haven't looked deeper, I've seen enough.

It doesn't matter how you load the image - there is a button each for  
the three methods I know about - all give the same results.

Beware! Vote for bug # 4026 !!
http://quality.runrev.com/qacenter/show_bug.cgi?id=4026

Jerry Jensen