Add transform parameter to sitemap items

[psychuk]

Which UI are you reporting an issue for?

• Basic UI
• HABPanel
• HABot
• CometVisu
• Sitemap

The problem

When using transforms there is no way for those transforms to be applied be applied to icons, label colours or icon colours. This I feel is a huge oversight.

Your suggestion

It would be helpful to pre-process values in a sitemap which would affect all other parameters dynamically.
Since a transform parameter does not already exist it would not break any existing code, as I am fully aware that would be the first excuse provided not to do it.

Either that or at the very least make transforms available in the labelcolor, icon and iconcolor parameters (this also would not break any existing code).

If I change a value using a transform it seems ridiculous to me that I have create complex workarounds and rules just to handle a simple display issue.

Your environment

Additional information

[lolodomo]

Please expose a use case and the concrete syntax you suggest, because what you request is not clear, at least for me. An example could probably help.

[psychuk]

Please expose a use case and the concrete syntax you suggest, because what you request is not clear, at least for me. An example could probably help.

Text item=Plant1_Temp label="Temperature [%.1f %unit%]" transform="double.js" icon="temperature"

double.js:

(function double(x) {
	console.log("double.js called with input: " + x);
	if (!isNaN(x)) return (x * 2);
	return 0;
})(input)

[lolodomo]

The transform is applied to what? The item value?
And what do you do of the result

[lolodomo]

Why not simply defining the transformation on the item itself?

[psychuk]

The transform is applied to what? The item value?

Yes, and this value applies to all the other properties (label, icon, colours, etc)

[psychuk]

Why not simply defining the transformation on the item itself?

OP:

When using transforms there is no way for those transforms to be applied be applied to icons, label colours or icon colours

[psychuk]

Why not simply defining the transformation on the item itself?

Yes, that's possible, the item will say whatever you want it to say, however the transformation only applies to what is displayed, all other properties reflect the actual state of the item. The transformed value should be passed to all the other properties too as the actual transformed state.

[lolodomo]

Just define a second item with the expected transformation and use that second item in your sitemap colour rules.
Very simple.

[psychuk]

Just define a second item with the expected transformation and use that second item in your sitemap colour rules.
Very simple.

With all due respect, comments like this sadden me.

Please explain why people need to create items that have no function other to workaround missing functionality.

It seems to me that openhab is either unwilling, unable or simply disinterested in evolving the existing functionality, very disappointing.

I already have dummy items to workaround not being able to compare one item with another item in a sitemap definition, now I have to add more, bloating my item and rule files, running rules that I shouldn't have to, IMHO.

This particular suggestion is by far the most trivial I have suggested in the past, there are many, what I believe to be, mistakes when the original system was designed.

While we are the subject of transforms, I cannot understand why the item itself is not sent to the transform. With an item parameter the user could transform based on the item, the items children, parent group, get the thing and access other channels, a whole plethora of addition functionality. If a user only wants to return a modified state then they can simply get the state from the item parameter. No fuss, no coconuts.

[lolodomo]

I was just mentioning there was already a simple way to do what you want.

Adding transform support in sitemap would be I believe a very complex enhancement. I am not sure it is worth it. But that's just my opinion and anyone can disagree with me and contribute such change.

Sorry I was just trying to help you, thinking you did not succeed in achieving your use case.