[mythtv] Couldn't save cache image: blank.png

[Joseph A. Caputo]

On Monday 24 November 2003 11:42, Michael McLagan wrote:
> Hello,
>
>    I've got a RH9 based system.  I built Myth based on the ATRPM spec
> file, minus ALSA.  It doesn't all work but I'm still trying to figure
>
> that out.  One thing at is consistantly broken is:
> > generating cache image for:
> > /usr/share/mythtv/themes/default/blank.png Couldn't save cache
> > image: /home/mythtv/.mythtv/themecache/blue.720.480/blank.png
>
> This happens for all themes that I've tried.  All the other images
> are cached but the blank.png one never is.  The result is that it
> keeps going thru the "prescaling" repeatedly.
>
> Permissions are fine (all others are scaled), the source file exists.
> I've tried wiping the themecache directory, etc but it won't stop
> doing this.
>
> Any thoughts?  Thanks,

Well, it looks like when the blank.png image gets scaled, a null image 
results (not to be confused with a NULL pointer... a null image is a 
valid QImage object, but with all zero data & values).  I guess Qt 
doesn't like trying to save a null image.  Now, why it's a null image 
in the first place, I'm not sure.  I guess it has something to do with 
the fact that the image only has a background layer, which seems to be 
either empty or a single color.  I don't know much about image layers & 
data, etc.  Somebody else can take it from here if they want.  We could 
have LoadScaleImage return NULL if a null image is the result of 
scaling, but you'd then get an error message about not being able to 
generate the scaled image (which actually might be more accurate, 
though...).  Note that the image is not null before scaling, it's only 
the result of calling QImage::smoothScale (I also tried QImage::scale) 
that's a null image.

-JAC