iimage.el and the size of the images

iimage.el and the size of the images

[Uwe Brauer]

Hello

I just learn about iimage.el, which is now part of GNU emacs core. I
like it quite a lot, the only thing which I find a bit inconvenient on
my 12 inch Laptop is the size of the images displayed. I did not find
any variable in which the size of images could be changed.


The author's address does not work anymore, so I looked at the code it
seems that the essential part is this:

  (if arg
                  (add-text-properties (match-beginning 0) (match-end 0)
                                       `(display ,(create-image file)
                                                  ^^^^^
                                         modification-hooks
                                         (iimage-modification-hook)))
            

Now I checked that function and its documentation says
,----
| 
| create-image is an autoloaded compiled Lisp function in ‘image.el’.
| (create-image FILE-OR-DATA &optional TYPE DATA-P &rest PROPS)
| Create an image.
| ....
| Images should not be larger than specified by ‘max-image-size’.
`----


However 
,----
| max-image-size is a variable defined in ‘C source code’.
| Its value is 10.0
`----

So I cannot change that value easily. Anybody has an idea how to change
the size of the displayed images?

thanks

Uwe Brauer 

Re: iimage.el and the size of the images

[Michael Heerdegen]

Uwe Brauer <oub@mat.ucm.es> writes:

> I just learn about iimage.el, which is now part of GNU emacs core. I
> like it quite a lot, the only thing which I find a bit inconvenient on
> my 12 inch Laptop is the size of the images displayed. I did not find
> any variable in which the size of images could be changed.

> The author's address does not work anymore, so I looked at the code it
> seems that the essential part is this:

>   (if arg
>                   (add-text-properties (match-beginning 0) (match-end 0)
>                                        `(display ,(create-image file)
>                                                   ^^^^^
>                                          modification-hooks
>                                          (iimage-modification-hook)))
            


Lars Ingebrigtsen has been working in that area recently.  He installed
some patches that made scaling displayed images very easy (in the master
branch AFAIK).

Lars, do your patches affect iimage.el as well - or should they?


> However 
> ,----
> | max-image-size is a variable defined in ‘C source code’.
> | Its value is 10.0
> `----
>
> So I cannot change that value easily.

Why not?  Doesn't `setq' change the value?

However, I'm not sure what this variable really means (I don't
understand the docstring).


Michael.

Re: iimage.el and the size of the images

[Uwe Brauer]

    > Uwe Brauer <oub@mat.ucm.es> writes:


            


    > Lars Ingebrigtsen has been working in that area recently.  He installed
    > some patches that made scaling displayed images very easy (in the master
    > branch AFAIK).

I have a relative recent version of 25.1.50 installed (but not the most
recent because of the changes in vc-hg.el). Not sure whether these
patches are in there. 

    > Lars, do your patches affect iimage.el as well - or should they?



    > Why not?  Doesn't `setq' change the value?

Ok, my bad it does, but it does not have any effect, so I presumed
values defined in C, cannot be changed in lisp or if that does not have
any effect. That might be wrong but on a practical level the variable
does not  help.


    > However, I'm not sure what this variable really means (I don't
    > understand the docstring).


Nor do I

Uwe 

Re: iimage.el and the size of the images

[Lars Ingebrigtsen]

Uwe Brauer <oub@mat.ucm.es> writes:

> Ok, my bad it does, but it does not have any effect, so I presumed
> values defined in C, cannot be changed in lisp or if that does not have
> any effect. That might be wrong but on a practical level the variable
> does not  help.

No, that variable is just a sanity check kinda thing and has nothing to
do with the iimage problem.  iimage just lacks a way to scale the
images, and it should have.  Report the problem with `M-x
report-emacs-bug' and somebody will probably implement it at some
point...

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Re: iimage.el and the size of the images

[Uwe Brauer]

>>> "Lars" == Lars Ingebrigtsen <larsi@gnus.org> writes:

   > Uwe Brauer <oub@mat.ucm.es> writes:
   >> Ok, my bad it does, but it does not have any effect, so I presumed
   >> values defined in C, cannot be changed in lisp or if that does not have
   >> any effect. That might be wrong but on a practical level the variable
   >> does not  help.

   > No, that variable is just a sanity check kinda thing and has nothing to
   > do with the iimage problem.  iimage just lacks a way to scale the
   > images, and it should have.  Report the problem with `M-x
   > report-emacs-bug' and somebody will probably implement it at some
   > point...

I'll do, but the code Michael mentioned, cannot be simply used?