Mapserver/GD JPEGs

[Jeff Hoffmann]

Stephen Davies wrote:
> Thanks Jeff.
> That seems to be the issue.
> How did you know that INTERLACE=OFF was relevant to JPEGs? As I read the 
> doco, it is only relevant for PNG and GIF images.

That's a good question.  You're right, it's not specifically stated in 
the documentation.  My guess is that it's something I remember from the 
GD library --  there's one function called gdImageInterlace that makes 
JPEGs progressive and PNG/GIF interlaced, so even if it's not 
specifically stated, it makes sense to work that way in MapServer.

> Do you now if phones have the same aversion to interlaced GIFs?

The only place I've had to mess with the INTERLACE option is with JPEGs. 
  I actually don't know for sure what the default is for PNG and GIF, 
but whatever it is seemed to work fine for me.

--
Jeff Hoffmann
Head Plate Spinner
PropertyKey.com