[R-package] Add R logo (fixes #3331, #3332)

[jameslamb]

This PR introduces a hex logo for the R package! (#3331) These logos are very popular in the R community (see, for example, https://github.com/rstudio/hex-stickers). Thanks to @guolinke for generating these logos.

It adds this file in man/figures/logo.png, the preferred place recognized by {pkgdown}.

Following @StrikerRUS 's suggestion in #3327 (comment), I also generated favicons for the site using pkgdown::build_favicons() (#3332).

{pkgdown} site looks good (if you squint you can see the favicon in the tab)

and this renders nicely in GitHub too!

[jameslamb]

@StrikerRUS I created this as a LightGBM branch so we can test on readthedocs. Could you enable the build there?

[StrikerRUS]

@jameslamb

Could you enable the build there?

Sure! Just enabled.
https://readthedocs.org/projects/lightgbm/builds/

[jameslamb]

* checking for future file timestamps ... NOTE
unable to verify current time

huh, never saw that before. Looking into it. Since that problem doesn't seem isolated to a particular operating system, R version, or build type, I would be surprised to learn that it's related to the changes in #3335

[StrikerRUS]

I think we should add LightGBM_logo_hex.svg into https://github.com/microsoft/LightGBM/tree/master/docs/logo to be consistent with our FAQ-15: You can find LightGBM's logo in different file formats and resolutions here. if one want to add hex logo.
@jameslamb Is it possible to copy file from ../docs/logo to the R-package target location at a build time or provide customized path with the aim to not duplicate files?

[jameslamb]

I think we should add LightGBM_logo_hex.svg into https://github.com/microsoft/LightGBM/tree/master/docs/logo to be consistent with our FAQ-15: You can find LightGBM's logo in different file formats and resolutions here. if one want to add hex logo.
@jameslamb Is it possible to copy file from ../docs/logo to the R-package target location at a build time or provide customized path with the aim to not duplicate files?

I did add the SVG there, but for the {pkgdown} stuff to work, I believe your logo file has to just be called logo.png and it has to be in man/figures. When I tried with other locations, it wasn't found when rendering the {pkgdown} site. I think it's ok for the PNG to be in the expected place in the R package (to make {pkgdown} work) and for the SVG to be in docs/logo.

[jameslamb]

* checking for future file timestamps ... NOTE
unable to verify current time

huh, never saw that before. Looking into it. Since that problem doesn't seem isolated to a particular operating system, R version, or build type, I would be surprised to learn that it's related to the changes in #3335

This was just reported on the r-pkg-devel mailing list. Apparently R CMD check --as-cran has a dependency on two small "what time is it right now" services. One of which doesn't work with the way R is asking it for the time, and the other of which is currently down 🙃

https://stat.ethz.ch/pipermail/r-package-devel/2020q3/005928.html

[jameslamb]

I'm able to reproduce the time problem on my laptop too. If it is still a problem a few hours from now, I'll just bump the number of allowed checks so our CI can passs.

We shouldn't stop all development on LightGBM just because R doesn't know what time it is 😂

[StrikerRUS]

@jameslamb

I did add the SVG there, ...

OK, I see. Seems there is no room for logo path customization. But at least, according to this, logo can be in SVG:
https://github.com/r-lib/pkgdown/blob/3b4d5b3d724d923973cc28f1c975833c8dba0f29/R/build-logo.R#L15

[jameslamb]

OK, I see. Seems there is no room for logo path customization. But at least, according to this, logo can be in SVG:
https://github.com/r-lib/pkgdown/blob/3b4d5b3d724d923973cc28f1c975833c8dba0f29/R/build-logo.R#L15

yep! It can be but it doesn't have to be. I've generated the favicons once from R-package/man/figures/logo.png. Are you saying I should re-do it with the SVG?

[StrikerRUS]

@jameslamb

Are you saying I should re-do it with the SVG?

Ah, no, I think there is no difference from which source those tiny images were generated. I meant place svg in man R-package/man/figures/logo.svg instead of png to have good scaling.

[jameslamb]

oh I see! Ok I can do that right now

[StrikerRUS]

Amazing, thank you!

Seems that pkgdown is happy too!

[jameslamb]

WOO awesome!

[github-actions]

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