Re: supporting mouse-entered, mouse-left

[Steve Yegge <stevey@google.com>]

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On Fri, Jul 31, 2009 at 8:38 AM, Drew Adams <drew.adams@oracle.com> wrote:

>        I would like to highlight certain identifiers (such as all uses
>        of a particular local variable in a function) simultaneously
>        when the mouse enters any of them.
>
>        I've scoured the documentation, and I don't see a way to
>        accomplish this feat.
>
>        Would it be reasonable to add mouse-entered and mouse-left
>        properties analogous to point-entered and point-left?
>
>        Alternately (or in addition), it might be nice to have text
>        properties analogous to the mouseenter, mouseleave and
>        possibly mouseover standard browser events, which would
>        fire at the granularity of pixels rather than characters.
>
> Maybe I'm misunderstanding, but if you mean highlight the text whenever the
> mouse is over it, you can do that using text property `mouse-face'. (That
> has
> character granularity however.)
>
> To have the mouseover highlight appear for certain words etc., you would
> need to
> apply property `mouse-face' to those words.
>
> AFAIK, font-lock cannot be used for this, since it always uses the `face'
> text
> property. (But maybe I'm wrong about that.) It might be an interesting
> feature
> for font-lock to let you specify a different text property to use.
>
>
I'm sorry if I was unclear.  Let me give an example.  In this sentence:

"One flew east, one flew west, and one flew over the cuckoo's nest."

I would like to arrange things in advance so that whenever the mouse is
over any instance of the word "flew", ALL of the instances highlight.

`mouse-face' is not powerful enough to accomplish this.

-steve

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