Re: [gDesklets] Newbie Developer Control Question

[Lauri Kainulainen <lauri sokkelo net>]

Hi Sean,

Sean Bridges wrote:
> Control Functions would need to be:
> * Handle grabbing Meta-data from image uri.  
> * Handle building a list of uris to pictures to display based on a
> passed directory.  Provide maybe a next picture, previous picture call
> that is hooked to a timer.  (Doesn't appear to be a standard 'directory'
> chooser preference, so that might have to just be a string for now?)

We don't have a directory chooser, but that's a very good idea. Perhaps 
something for 0.40.

> If I understand right each of these functions would need to happen
> inside a control, not possible from a display.  Is that correct?  

Yes. That's correct. Basically display-files can't do anything that is 
not (a) done through the ADL-language (the xml you use to define the 
displays), (b) done through a control, (c) built in Python (the stuff 
you get when you do python -i and don't import anything)

> I browsed through the controls on the site and I didn't find any that
> appeared to help with this.  Is there anything out there that I should
> re-use?  

Can't think of anything if you found nothing on the official site 
(gdesklets.de) or on the archive that can be found through the official 
site.

> Finally, if I have to make a control, I'm thinking it should be called
> something like ImageManipulation.  Methods could be added do resizing or
> transitions later down the road.  

Sounds very reasonable. First I'd start thinking about the 
property-based control interface. For the requirements you mentioned 
earlier, I'd say you need something like this (just an example):

image_uri <- set this to the target image...
meta_data <- ... and then read this to get the meta-data in a dictionary
pictures <- get/set to manipulate the list of pictures
start_slideshow <- start a loop do show pictures
next_picture <- switch to next picture manually
prev_picture <- ....

Then you just build the functions that handle getting and setting those 
python properties.

If you have any questions feel free to post them on the list!


- Lauri
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