Calculate window size in pixels

Calculate window size in pixels

[Mathias Dahl]

Is it possible to calculate an Emacs window's size in pixels?
`window-height' and `window-width' returns lines and columns.

I guess this have to do with the frame's default font or
something. Having two functions, `window-height-pixels' and
`window-width-pixels' would be nice :)

Can it be done?

The reason that I want this is to be able to figure out to what size I
have to resize an image to before inserting it into a window, so that
it fits snugly.

/Mathias

Re: Calculate window size in pixels

[Pascal Bourguignon]

Mathias Dahl <brakjoller.rem0veth1s@gmail.com> writes:

> Is it possible to calculate an Emacs window's size in pixels?
> `window-height' and `window-width' returns lines and columns.
>
> I guess this have to do with the frame's default font or
> something. Having two functions, `window-height-pixels' and
> `window-width-pixels' would be nice :)
>
> Can it be done?
>
> The reason that I want this is to be able to figure out to what size I
> have to resize an image to before inserting it into a window, so that
> it fits snugly.

It depends on the window manager.  With X, (when (eq window-system 'x) 
you'd use:
   x-display-pixel-width
   x-display-pixel-height
)


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
Until real software engineering is developed, the next best practice
is to develop with a dynamic system that has extreme late binding in
all aspects. The first system to really do this in an important way
is Lisp. -- Alan Kay

Re: Calculate window size in pixels

[Stefan Monnier]

> Is it possible to calculate an Emacs window's size in pixels?
> `window-height' and `window-width' returns lines and columns.

There's frame-pixel-height in Emacs-CVS.
There's also window-pixel-edges if you care about windows rather
than frames.


        Stefan

Re: Calculate window size in pixels

[Klaus Straubinger]

Stefan Monnier <monnier@iro.umontreal.ca> wrote:

>> Is it possible to calculate an Emacs window's size in pixels?
>> `window-height' and `window-width' returns lines and columns.
>
> There's frame-pixel-height in Emacs-CVS.

This function is even available in the released version Emacs 21.4.

> There's also window-pixel-edges if you care about windows rather
> than frames.

This seems to be a new function in the yet to be released Emacs 22.1.

-- 
Klaus Straubinger

Re: Calculate window size in pixels

[Mathias Dahl]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> > Is it possible to calculate an Emacs window's size in pixels?
> > `window-height' and `window-width' returns lines and columns.
> 
> There's frame-pixel-height in Emacs-CVS.
> There's also window-pixel-edges if you care about windows rather
> than frames.

Which means I can use this:

(defun window-height-pixels ()
  (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height)))
        (column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
    (ftruncate (* (window-height) line-pixel-height-ratio))))

(defun window-width-pixels ()
  (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
    (ftruncate (* (window-width) column-pixel-width-ratio))))

I see that the frame-pixel-functions is including window
decorations and stuff, but I guess it can work for my
purposes anyway.

Thanks!

/Mathias

Re: Calculate window size in pixels

[Mathias Dahl]

Mathias Dahl <brakjoller@hotmail.com> writes:

 
> Which means I can use this:
> 
> (defun window-height-pixels ()
>   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height)))
>         (column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>     (ftruncate (* (window-height) line-pixel-height-ratio))))
> 
> (defun window-width-pixels ()
>   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>     (ftruncate (* (window-width) column-pixel-width-ratio))))

And even better:

(defun window-height-pixels ()
  (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
    (truncate (* (window-height) line-pixel-height-ratio))))

(defun window-width-pixels ()
  (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
    (truncate (* (window-width) column-pixel-width-ratio))))

/Mathias

Re: Calculate window size in pixels

[Mathias Dahl]

Mathias Dahl <brakjoller@hotmail.com> writes:

> And even better:
> 
> (defun window-height-pixels ()
>   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
>     (truncate (* (window-height) line-pixel-height-ratio))))
> 
> (defun window-width-pixels ()
>   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>     (truncate (* (window-width) column-pixel-width-ratio))))

Shameful plug:

You can now see this in action in `tumme-display-image' in
the newest version of tumme.el:

 http://www.emacswiki.org/cgi-bin/wiki/Tumme

/Mathias

Re: Calculate window size in pixels

[Kevin Rodgers]

Mathias Dahl wrote:
> (defun window-height-pixels ()
>   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
>     (truncate (* (window-height) line-pixel-height-ratio))))
> 
> (defun window-width-pixels ()
>   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>     (truncate (* (window-width) column-pixel-width-ratio))))

I think (+ (frame-pixel-DIMENSION) 0.0) can be replaced by
(float (frame-pixel-DIMENSION))

-- 
Kevin Rodgers

Re: Calculate window size in pixels

[Mathias Dahl]

Kevin Rodgers <ihs_4664@yahoo.com> writes:

> Mathias Dahl wrote:
> > (defun window-height-pixels ()
> >   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
> >     (truncate (* (window-height) line-pixel-height-ratio))))
> > (defun window-width-pixels ()
> >   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
> >     (truncate (* (window-width) column-pixel-width-ratio))))
> 
> I think (+ (frame-pixel-DIMENSION) 0.0) can be replaced by
> (float (frame-pixel-DIMENSION))

It can :), thanks! Looks better.

/Mathias

Re: Calculate window size in pixels

[Ehud Karni]

On 06 May 2005 17:40:41 +0200, Mathias Dahl wrote:
>
> (defun window-height-pixels ()
>   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
>     (truncate (* (window-height) line-pixel-height-ratio))))
>
> (defun window-width-pixels ()
>   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>     (truncate (* (window-width) column-pixel-width-ratio))))

I think that `frame-char-height' and `frame-char-width' is what you
are looking for.

I use the following to change the font without resizing the frames. This uses
only the `editable' part of the frame - without the border and menus areas.

(defun set-font-keep-size (font)
  "set font to use, keep window size"
       (let ((fht (* (frame-parameter nil 'height) (frame-char-height)))
             (fwd (* (frame-parameter nil 'width)  (frame-char-width))))
           (set-default-font font)
           (set-frame-value-all 'font font)
           (set-frame-value-all 'height (/ fht (frame-char-height)))
           (set-frame-value-all 'width  (/ fwd (frame-char-width)))))

`set-frame-value-all is my function to set a value on all frames.

Ehud.


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Re: Calculate window size in pixels

[Mathias Dahl]

"Ehud Karni" <ehud@unix.mvs.co.il> writes:

> On 06 May 2005 17:40:41 +0200, Mathias Dahl wrote:
>>
>> (defun window-height-pixels ()
>>   (let ((line-pixel-height-ratio (/ (+ (frame-pixel-height) 0.0) (frame-height))))
>>     (truncate (* (window-height) line-pixel-height-ratio))))
>>
>> (defun window-width-pixels ()
>>   (let ((column-pixel-width-ratio (/ (+ (frame-pixel-width) 0.0) (frame-width))))
>>     (truncate (* (window-width) column-pixel-width-ratio))))
>
> I think that `frame-char-height' and `frame-char-width' is what you
> are looking for.
>
> I use the following to change the font without resizing the frames. This uses
> only the `editable' part of the frame - without the border and menus areas.
>
> (defun set-font-keep-size (font)
>   "set font to use, keep window size"
>        (let ((fht (* (frame-parameter nil 'height) (frame-char-height)))
>              (fwd (* (frame-parameter nil 'width)  (frame-char-width))))
>            (set-default-font font)
>            (set-frame-value-all 'font font)
>            (set-frame-value-all 'height (/ fht (frame-char-height)))
>            (set-frame-value-all 'width  (/ fwd (frame-char-width)))))
>
> `set-frame-value-all is my function to set a value on all frames.

That seems to be exactly what I wanted. Strange I missed it. I will
try using that instead and see how it works.

Thanks!

/Mathias

Re: Calculate window size in pixels

[Mathias Dahl]

Mathias Dahl <brakjoller.rem0veth1s@gmail.com> writes:

>> I think that `frame-char-height' and `frame-char-width' is what you
>> are looking for.

> That seems to be exactly what I wanted. Strange I missed it. I will
> try using that instead and see how it works.

It worked very well and feels much better than trying to calculate the
pixel/character ratio myself.

Thanks again!

/Mathias