> I've written a python script that reads some data from a file and generates a
> .png image. I want to have a button on my MIDAS status page that:
> - executes the script and waits for it to finish,
> - then displays the image
> How can I do that? I tried using the sequencer to just execute the script every
> 30 seconds, but I can't get it to work, and it would be better to only execute
> the script on demand anyway.
> I also am having trouble getting image display to work. I have the ODB keys set:
> Temperature Map& /home/deap/ovendaq/online/index.html
> [local:oven1:S]/Custom>ls Images/temps.png/
> Background /home/deap/ovendaq/online/temps.png
> And the HTML file is just this:
> <img src="temps.png">
> But the image won't display. It shows a "broken" picture, and when I try to view
> it directly it says: Invalid custom page: Page not found in ODB.
> Any help would be appreciated...
If you use the "custom" image system, you need to use GIF images. mhttpd can dynamically create GIF
with a background image and overlaid labels, bar graphs etc. But mhttpd just contains a GIF library to do
in memory, but no PNG library.
Actually I would recommend you not to use a script to create an image, but use the custom image system
display temperatures. In the attachment you see an page from our experiment which contains a
background image (the greyish boxes), labels (white temperature boxes), bar graphs (blue level boxes)
and history pages (left side). This is all dynamically created inside mhttpd using the custom page system
without any external script. All you have to do is to get the temperatures and levels inside the ODB via the
slow control system. If you want, I can send you the full code for that page.