Re: [Pan-users] Re: Previews gone screwy

[Dave Chand]

On Oct 6, 2007, at 6:58 PM, Greg Lee wrote:

> Is it the decoding? When I save the decoded jpeg files with Pan
> and view them with a different viewer program, they seem perfectly  
> okay.
>
> I looked at the two image files that stevem refers to, and I get
> the same results as he: "Denali Sunrise" at 298559 bytes (as reported
> by Pan) views ok, but "Lake Pend Oreille" at 423726 bytes displays
> incorrectly.
>
> I looked at some other 1 part images in this same newsgroup and
> found that all those with byte size <= 369052 displayed correctly,
> but all those with byte size >= 369361 displayed incorrectly.  Of
> the two dozen or so that I tried.

I have been experimenting with gdk-pixbuf. What I find is the following:
in the file gtk+2.12.x/gdk-pixbuf/io-jpeg.c
there is the statement
#define JPEG_PROG_BUF_SIZE 65536
if you change its value to something significantly higher, such as
#JPEG_PROG_BUF_SIZE 500000
then it seems the decoding problems go away.

Can someone with some knowledge of gtk please comment on this?


dc.