image instance/specifier/instantiator

image instance/specifier/instantiator

[Lars Magne Ingebrigtsen]

I'm misunderstanding something.

To make an image specifier I do this:

      (make-image-specifier
       (vector (intern type) :data (buffer-string)))

This works, and I use this to make an annotation that I insert.

However, I would like to know the height and width of the image,
before I decide whether to display it inline out externally.  I can't
use annotations for that, since we only have annotation-width, but not 
annotation-height.  However, we have image-instance-width, so I though 
I could just instatiate an image, but `make-image-instance' called
with an image specifier doesn't work.  It needs, uh, something else.
But what?  I have no idea.

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@ifi.uio.no * Lars Magne Ingebrigtsen

Re: image instance/specifier/instantiator

[Hrvoje Niksic]

Lars Magne Ingebrigtsen <larsi@ifi.uio.no> writes:

> However, I would like to know the height and width of the image,
> before I decide whether to display it inline out externally.  I
> can't use annotations for that, since we only have annotation-width,
> but not annotation-height.

That's quite strange.  Anyway, if I were you, I'd try with
(glyph-width (annotation-glyph ...)) and
(glyph-height (annotation-glyph ...)).

BTW, why do you create image specifiers at all?  I don't think you
need to do that -- an instantiator should suffice.

-- 
Hrvoje Niksic <hniksic@srce.hr> | Student at FER Zagreb, Croatia
--------------------------------+--------------------------------
The end of the world is coming...  SAVE YOUR BUFFERS!

Re: image instance/specifier/instantiator

[Lars Magne Ingebrigtsen]

Hrvoje Niksic <hniksic@srce.hr> writes:

> That's quite strange.  Anyway, if I were you, I'd try with
> (glyph-width (annotation-glyph ...)) and
> (glyph-height (annotation-glyph ...)).

Thanks; this does the trick.

> BTW, why do you create image specifiers at all?  I don't think you
> need to do that -- an instantiator should suffice.

Er...  I though

      (make-image-specifier
       (vector (intern type) :data (buffer-string)))

was the simplest way to create an image?  This can later be fed to
`make-annotation' for insertion into the buffer...

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen

Re: image instance/specifier/instantiator

[Hrvoje Niksic]

Lars Magne Ingebrigtsen <larsi@gnus.org> writes:

> > BTW, why do you create image specifiers at all?  I don't think you
> > need to do that -- an instantiator should suffice.
> 
> Er...  I though
> 
>       (make-image-specifier
>        (vector (intern type) :data (buffer-string)))
> 
> was the simplest way to create an image?

Well, it creates an image specifier, which contains information how
the image should be displayed on various devices.  In XEmacs parlance,
the actual image in buffer is in called a "glyph", and the easiest way
to create it is using an instantiator, without mucking with image
specifiers at all (leave that to the internal code.)  For instance:

;; I like backquotes
(setq my-glyph (make-glyph `[,(intern type) :data ,(buffer-string)]))

Now, you can attach `my-glyph' at the beginning or an end of an extent
(this is considered "low-level"), or feed it to `make-annotation'.
The specifier will, of course, still be there:

(glyph-image my-glyph)
  => #<image-specifier global=((x) . [gif :file "/home/srce/hniksic/pics/kreten.gif" :data "GIF87a..."]>

XEmacs' interface to images may be a bit confusing at first; if you
don't understand how it works, feel free to ask.  Also, I've found
that chapter in the manual quite well written (but that's me.)

-- 
Hrvoje Niksic <hniksic@srce.hr> | Student at FER Zagreb, Croatia
--------------------------------+--------------------------------
You're never alone with schizophrenia.

Re: image instance/specifier/instantiator

[Lars Magne Ingebrigtsen]

Hrvoje Niksic <hniksic@srce.hr> writes:

> Well, it creates an image specifier, which contains information how
> the image should be displayed on various devices.  In XEmacs parlance,
> the actual image in buffer is in called a "glyph", and the easiest way
> to create it is using an instantiator, without mucking with image
> specifiers at all (leave that to the internal code.)  For instance:
> 
> ;; I like backquotes
> (setq my-glyph (make-glyph `[,(intern type) :data ,(buffer-string)]))

Ah, right.

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen