Q on multiple faces as text property `face'

Q on multiple faces as text property `face'

[Drew Adams]

I have two faces:
(defface face1 '((t (:background "White"))) "Face 1")
(defface face2 '((t (:foreground "Blue"))) "Face 2")

Using `put-text-property' with the `face' property:
  I put face2 on some text.
  I put face1 on some text.

I would like the result to show, wherever both faces are applied to the same
text, both a Blue foreground and White background. However, what happens is
that the last face applied takes precedence - the other face contributes
nothing.

I also tried with definitions like this, also to no avail:
(defface face1 '((t (:background "White" :foreground unspecified))) "1")
(defface face2 '((t (:foreground "Blue"  :backround unspecified))) "2")

What's the correct way to do what I want: accumulate (merge) properties from
different faces? (No, I don't want to use overlays here.)

I've consulted the Elisp manual, looked through the code in `faces.el', and
`grep'ed for occurrences of `unspecified' in the Emacs Lisp sources, but
it's still not clear to me how this is supposed to work.

Re: Q on multiple faces as text property `face'

[Johan Bockgård]

"Drew Adams" <drew.adams@oracle.com> writes:

> I have two faces:
> (defface face1 '((t (:background "White"))) "Face 1")
> (defface face2 '((t (:foreground "Blue"))) "Face 2")
>
> Using `put-text-property' with the `face' property:
>   I put face2 on some text.
>   I put face1 on some text.
>
> I would like the result to show, wherever both faces are applied to
> the same text, both a Blue foreground and White background. However,
> what happens is that the last face applied takes precedence - the
> other face contributes nothing.

It doesn't "take precedence".

    put-text-property is a built-in function in `C source code'.
    (put-text-property START END PROPERTY VALUE &optional OBJECT)

    Set one property of the text from START to END.
    ^^^
The value of the `face' property is replaced altogether.

> I also tried with definitions like this, also to no avail:
> (defface face1 '((t (:background "White" :foreground unspecified))) "1")
> (defface face2 '((t (:foreground "Blue"  :backround unspecified))) "2")

Obviously changing the face definitions will make no difference.

> What's the correct way to do what I want: accumulate (merge) properties from
> different faces? (No, I don't want to use overlays here.)

The value of the face property may be a list. Use/see
`font-lock-prepend-text-property' or `font-lock-append-text-property'.

-- 
Johan Bockgård