UI filters should give user feedback when they are valid

[texodus]

No description provided.

[Ro4052]

I've been having a look at this issue but wasn't sure of the best way to approach the problem. My current approach is a function on the Perspective table to check whether a filter is valid, which can be called from the viewer. Invalid filters can then be highlighted and not passed with the other filters into the new view. One area to investigate is the best way to highlight a filter, I'm currently just using a dashed red line.

I'm not sure if this is the most appropriate approach but hopefully it’s a start for addressing this issue. I've been working on it on this branch:

https://github.com/Ro4052/perspective/tree/invalid-filters

[texodus]

@Ro4052 This looks rad! Pretty much precisely what I had in mind - to give the user some feedback whether the filter they've entered has affected the data set. I think we would pretty happily accept a PR as is.

Re: styling - we've been applying Material guidelines as convenient, so if you are looking for inspiration the Google Material Guidelines are pretty much indisputable (for the material.css themes at least) - these do a red underline, red overlabel and red warning icon right floated. I think at this point in development though, these should be viewed as inspiration rather than devotion - what you have looks good to me and is certainly a clear functional improvement over what's in 0.2.11

[Ro4052]

I've had a little look at the material guidelines.

Would this be more suitable? This approach ended up being a little more involved but is perhaps more appropriate?

[texodus]

Looks awesome - when you're ready open a PR for this branch and we'll get it merged!

[Ro4052]

Thanks for the feedback. It's still a bit of a work in progress and needs some cleaning up. I'm still also looking at ways to improve the styling.

[texodus]

Thanks for the report, and fix! This has been released in 0.2.12