Twenty Fifteen: add support for site logos

[celloexpressions]

I'd suggest putting it above the site title and tagline in the sidebar, and possibly not showing it at all on mobile where the sidebar becomes a header. I've had users specifically want to add a logo to this theme, in this location before. And, we should ship with more than one bundled theme supporting the featured. It could work for twenty fourteen as well, but it's less convincing there.

I'm attaching the rough version I did while testing the feature, it could use the addition of a bottom margin, decision of a proper size setting, and consideration of the ability to hide the site title and tagline when there's a logo.

[celloexpressions]

The raw basics - needs some refinement.

[drebbits.web]

Replying to celloexpressions:

...consideration of the ability to hide the site title and tagline when there's a logo.

They could just use the Display Site Title and Tagline option to pro-actively hide the site title and tagline.

I've provided little edits to the initial diff. I'm thinking placing a reference link in the doc block but that could be updated when we update the codex with site-logo theme support.

[iamtakashi]

The logo implementation touches the design of the theme so I'm gonna work on this today.

[iamtakashi]

I've added the support with some style refinements. The logo is smaller in small screens but but I'm not going to hide it.

The patch assumes the theme to be next version, 1.5.

[karmatosed]

Changes site-logo to custom-logo as per latest updates on feature

[karmatosed]

I've refreshed that patch as the naming has changed to custom-logo. If I could get a second pair of eyes on it before I commit that would be great just as a test. @iamtakashi if you have time would like you to test for me.

The name change for the body is dependent on: https://core.trac.wordpress.org/ticket/35945. Once that's been approved we can then commit this but this patch does depend on this.

If that happens today gmt I'll commit this, otherwise it will be Tuesday later when I'll next get a commit chance as travelling. I'm totally happy someone committing this in my absence though as it may need to just ship :) @mikeschroder I'll let you decide if that patch in dependent ticket drops while I'm away.

[iamtakashi]

Assuming the body class is going to be added back, 35944.4.diff looks good to me.

[celloexpressions]

Can we clarify in the inline comment that twentyfifteen_the_custom_logo() exists only for backwards compatibility with WordPress <4.5? At first glance it looks unnecessary, and if its purpose is clarified, it could be safely removed by developers basing themes off of Twenty Fifteen if they don't need to support older versions.

[iamtakashi]

Replying to celloexpressions:

The check inside it is obviously for backwards compatibility as well as for the case like the theme support is removed in child themes for whatever the reasons, at the same time, it allows the template cleaner.

[chriscct7]

Status: ​https://wordpress.slack.com/archives/core/p1457560799004558

[karmatosed]

In 36913:

Twenty Fifteen: add support for site logos
Fixes #35944
Props @iamtakashi, @celloexpressions, @drebbits.web

[obenland]

In 36943:

Twenty Fifteen: Simplify twentyfifteen_the_custom_logo().

See ​https://github.com/WordPress/twentysixteen/commit/b72e3d8059542542acbd0fdb15f54799109fbf82
See #35944.

[DrewAPicture]

Wrong ticket.