theme: Add different ticks length for different axes

[pank]

Hi,

I would like to add support for different ticks length for different axes (basically extending axis.ticks.length).
My main motivation is to match an Excel theme that I have been given, which features upwards ticks on the x-axis. I don't want inwards ticks on the y-axis though.

It was first requested in issue #1319.

Related pull request 2934.

My answers to comments submitted to the pull requests:

@batpigandme wrote:

PS As for styling, you can use the styler package to implement the in-house style as described in the tidyverse style guide.

Thanks, I will check that. I think it might also be possible to configure ESS to do tidyverse style these days...

@clauswilke

I've wanted this option in the past, so I'd generally be in favor. Not sure if it can be done without the clutter of adding all these new theme elements.

That's a good idea. We could use a "list" like for margins. Would it make sense to allow axis.ticks.length to be either a unit or a "list" with top, bottom, left, right? Is there any precedence for allowing two types?
The good things about having a new element in theme for each is that it makes auto-completion easy (at least in ESS and I'd assume Rstudio as well, but I'm not sure).

For the theme calculation code, you could probably just write: ...

Thanks! I could see if I within or with works here. That would make is less cluttered as well...

[clauswilke]

There's also another issue, more a question for @hadley: We have a solid inheritance system for elements, but we don't for units, such as axis.ticks.length discussed here or similarly legend.spacing and probably a few others. We always handle unit inheritance in a one-off fashion, as in:

theme$axis.ticks.length.x.bottom <- theme$axis.ticks.length.x.bottom %||% theme$axis.ticks.length.x %||% theme$axis.ticks.length

Would it make sense to add a function that can calculate these units based on the theme and the inheritance tree?

[pank]

Would it make sense to add a function that can calculate these units based on the theme and the inheritance tree?

I'm happy to add something like this if you point me in the right direction. (I must admit that I was a bit surprised that inheritance did not occur "automatically" given the second argument to `el_def`).

[clauswilke]

Closed via #2934.

[lock]

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