Ensure that Dimension parameters are consistently respected

[philippjfr]

Dimension objects in HoloViews define a wide range of parameters which are not always consistently respected. I therefore wanted to open a meta-issue to collect various examples where we could adhere to the dimensions more consistently.

Dimension.type

• Should define the type of the axis, i.e. numeric, categorical or datetime (Dimension.type should determine axis types #1312)
• Should allow defining the type of widget (eventually with more flexibility after the widget refactor)

Dimension.values

• Use as explicit order when plotting GridSpace
• Use as categories on categorical axis

Please feel free to add other cases.

[jlstevens]

I know we want to get rid of extents and have plotting ranges (e.g xlim, ylim etc) but will that override the dimension ranges? I know there is soft_range but I find that is very rarely used in practice...

[philippjfr]

I know we want to get rid of extents and have plotting ranges (e.g xlim, ylim etc) but will that override the dimension ranges?

Yes explicitly set ranges at the plot level should have highest precedence just like extents do now.

I know there is soft_range but I find that is very rarely used in practice...

I don't think that's an issue, it's used and consistently respected, my main worry is about Dimension parameters which are only partially respected.