New CSS parser for JavaFX

[Andy Goryachev]

I wonder if this could be done as an incubator module, or hidden behind an experimental system property.

-andy


From: openjfx-dev <openjfx-dev-retn at openjdk.org> on behalf of Kevin Rushforth <kevin.rushforth at oracle.com>
Date: Monday, August 26, 2024 at 14:40
To: openjfx-dev at openjdk.org <openjfx-dev at openjdk.org>
Subject: Re: New CSS parser for JavaFX
Deprecating the existing API is an interesting idea, but with such a
large API surface it will be difficult to show that no application is
using it.

-- Kevin


On 8/26/2024 2:35 PM, John Hendrikx wrote:
>
> On 26/08/2024 22:42, Michael Strauß wrote:
>>> can we create stylesheets programmatically without parsing (i.e.
>>> construct the token tree directly)?
>> Maybe, but `Stylesheet` and its constituent classes really seem like
>> exposed implementation details of JavaFX. I would rather deprecate
>> their use and remove them from the public API eventually.
>
> I'm pretty convinced of that as well.  The whole CSS API seems to have
> been put in place to allow use of binary stylesheets (to perhaps
> load Modena .5 seconds faster?), it doesn't seem to serve much of a
> function beyond that.  I haven't found a use for any of these classes
> and the API surface they expose.
>
> For example, I implemented a LESS parser that I can use with JavaFX,
> and the CSS API was absolutely no help there (what is the point of
> being able to create a StyleSheet when I can't "set" it on a Scene?)
> -- instead I've just resorted to writing the LESS output to memory
> buffers, and pointing my stylesheet properties directly to these
> (using "data:text/css;charset=UTF-8;base64," URL's -- thanks for
> whoever mentioned "data" URL's, I was writing these to temporary files
> before that...).
>
> The CSS API classes are also full of observable properties, which
> seems a rather odd decision given that a Stylesheet is probably far
> better represented as something immutable.  Imagine assigning a
> Stylesheet type to Scene (something that isn't possible, so it is
> unclear what the purpose of this class is), then having the CSS engine
> observe almost every aspect of this Stylesheet, just in case someone
> decides to add a new Selector somewhere programmatically... it would
> be incredibly complicated to "act" on such a change correctly,
> requiring no doubt thousands of lines of code, that will likely never
> ever be used in any FX application (well perhaps if you are writing a
> Stylesheet editor, but that's hardly a use-case worth supporting just
> in case...)
>
> --John
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