IRC inverted colour scheme doesn't map to Matrix

[kegsay]

https://matrix.org/jira/browse/BOTS-157

Notably background colours.

[kegsay]

Punting this due to other more pressing issues for the next release.

[lukebarnard1]

Seems that vector is pretty strict when it comes to displaying anything other than <b> etc. and <font color="...">. It's likely that the client is filtering out all of the html that it doesn't like, so this could be an issue with any client that doesn't just blindly spam HTML that it believes to be safe.

So, this is an issue with vector or any client that filters out certain tags. There doesn't seem to be any documentation on the org.matrix.custom.html format. Matrix sanitizes html with this: https://github.com/matrix-org/matrix-react-sdk/blob/24223ae2b69debb33fa22fcda5aeba6fa93c93eb/src/HtmlUtils.js. The https://github.com/punkave/sanitize-html package is used, which doesn't actually provide a way of only allowing certain CSS properties. It could be modified slightly to allow this filtering.

[lukebarnard1]

@dbkr suggests stripping the foreground colour when background colour is used. The reason being, when you have IRC asking for white text on black background (and say for the sake of argument a client has it's background set to white), if just the bg is stripped, the text isn't visible in the client. By stripping the foreground, you at least have legible text.

[ara4n]

stripping foreground colour would conversely risk black-on-black text
for intverted text for typical clients which have a dark-on-light
colourscheme.

Why wouldn't we just keep the colours intact?

On 28/07/2016 10:23, Luke Barnard wrote:

@dbkr https://github.com/dbkr suggests stripping the foreground
colour when background colour is used. The reason being, when you
have IRC asking for white text on black background (and say for the
sake of argument a client has it's background set to white), if just
the bg is stripped, the text isn't visible in the client. By
stripping the foreground, you at least have legible text.

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[lukebarnard1]

An alternative is to create a custom tag transformation that takes
<font color="..." bgcolor="...">...</font>
and replaces it with
<font style="color:...;background-color:...">...</font>.

[ara4n]

making up our own HTML attributes feels like a bad idea, and obviously we can't allow arbitrary CSS. I guess we could do something a bit dodgy like <font color="" data-matrix-bg-color="..."/> to specialcase it... :S

[kegsay]

Unassigned; we have more pressing issues than this.

[lukebarnard1]

So, now that Riot supports data-mx[-bg]-color, this can be done!

[joepie91]

Resurrecting this bug because it actually caused a knock-on bug, breaking auto-URLs in Riot (names redacted for privacy):

Producing this source, after bridging:

The original on IRC looked like this:

[Mikaela]

I think #1548 is somewhat related issue.