Add config option to disable print html, css, and icon

[rossmacarthur]

This PR adds a new config option which allows you to disable all "print" support.

[output.html.print]
enable = false

Resolves #1177

[Dylan-DPC-zz]

No issues. We are open to config changes

[ehuss]

Yea, seems fine.

Just one minor thing, I kinda prefer to avoid double negatives (no-foo=false). Maybe make the option name "print-enabled" with a default of true? Or maybe just print?

Also, I'm just curious, what's your motivation for this?

[DannyBen]

Just one comment about this PR:

I see that it completely disables the "print.css" - is this a good thing to do?
People can still print any page without having to click an HTML-rendered button, and when they do, they should still see a valid CSS specialized for print, without sidebar etc.

---

To answer the motivation question, at least from my standpoint:

First, I must say It is super great that this feature exists in the first place - I usually want it enabled.

The general use case for disabling it, is to prevent the ease of copyright violation. Sometimes we use mdbook to build a static site, and like most other websites, we do not want to provide a "download the entire site as PDF" option. If you want to read it, you come here.

A more particular use case I have (but with the same principle), is that I want to share a book that is normally only used internally, with someone external for a short period for review. The material is confidential, and should not be downloaded, only read.

[rossmacarthur]

@ehuss I changed the config setting to be a subtable. I think this is better because we can add extra settings later if we want and it mirrors the way fold settings are done.

[ehuss]

I would kinda prefer to avoid adding a new subtable, unless there is some expectation that there will actually be additional keys. If in the future we decide we need additional keys, we can always upgrade it to a subtable. I think a simple print = false would be sufficient.

[rossmacarthur]

I don't need this anymore and I don't think I have time to continue working on this PR. Someone else is welcome to branch off this and open a new PR.

[kalindkaria]

Hi, can I know why this PR is closed without merging the feature of disable printing to master branch?
This is a good feature to have, even I would like to have it in mdBook.
@rossmacarthur and @ehuss any comments?

[ehuss]

I'll go ahead and merge. The implementation looks good, and I don't feel too strongly about whether or not the config is a separate table. I can imagine extra print options being added in the future.

[kalindkaria]

Thanks @ehuss for the quick response. I can now use the following to disable the print option.

[output.html.print]
enable = false

But, the print button at top-right is still visible, yeah I agree on clicking it returns 404, as print.html file doesn't exist now.
Is there a way to even remove that button or this feature is not yet requested for or added?

[ehuss]

@kalindkaria Oops, thanks for checking! I should have reviewed more closely, there is a ! where it shouldn't have been. Posted #1335 to fix.

[kalindkaria]

Yes! @ehuss Thanks alot for adding this feature.