Emacs fullscreen and sizes in frame parameters

Emacs fullscreen and sizes in frame parameters

[David Engster]

I'd like Emacs to display an image so that it spans the *entire* screen
from top to bottom. That means: just the image, no window decorations or
anything else.

I know that Emacs frames can only have pixel-sizes which are multiples
of the character width and height. Still, I was hoping that I could
achieve that by simply making the frame a bit larger. However, it seems
I cannot resize the frame when the 'fullscreen' parameter is set to
'fullboth', which (I think) is the only way to get rid of the window
decorations. Is this really the case or am I missing something?

Here's what I've tried (you need an Imagemagick-enabled Emacs for this,
and I guess the x-display-* thingies only work under X11):

(let* ((cols (/ (x-display-pixel-width)
		(frame-char-width)))
       (lines (/ (x-display-pixel-height)
		 (frame-char-height))))
  (with-selected-frame
      (make-frame
       '((minibuffer . nil)
	 (left-fringe . 0)
	 (right-fringe . 0)
	 (menu-bar-lines . 0)
	 (vertical-scroll-bars . nil)
	 (tool-bar-lines . 0)
	 (fullscreen . fullboth)))
    (modify-frame-parameters
     nil
     `((width . ,(1+ cols))
       (height . ,(1+ lines))))
    (switch-to-buffer (get-buffer-create "test"))
    (setq mode-line-format nil)
    (insert-image
     (create-image "someimagefile" 'imagemagick nil
		   :height (x-display-pixel-height)))))


If you evaluate this, you'll get an empty buffer in a fullscreen Emacs
frame, and as you can see I set 'width' and 'height' slightly bigger
than the actual viewport, but it seems this doesn't have any effect
since the image is still truncated at the bottom, at least if

(mod (x-display-pixel-height) (frame-char-height))

is not zero, which is mostly the case.

So, is there any possibility to reliably display an image with ':height
(x-display-pixel-height)', so that it is not truncated?

-David

Re: Emacs fullscreen and sizes in frame parameters

[Eli Zaretskii]

> From: David Engster <deng@randomsample.de>
> Date: Sun, 09 Jun 2013 00:04:57 +0200
> 
> it seems I cannot resize the frame when the 'fullscreen' parameter
> is set to 'fullboth', which (I think) is the only way to get rid of
> the window decorations. Is this really the case or am I missing
> something?

Yes, this is by design.

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

Eli Zaretskii writes:
>> From: David Engster <deng@randomsample.de>
>> Date: Sun, 09 Jun 2013 00:04:57 +0200
>> 
>> it seems I cannot resize the frame when the 'fullscreen' parameter
>> is set to 'fullboth', which (I think) is the only way to get rid of
>> the window decorations. Is this really the case or am I missing
>> something?
>
> Yes, this is by design.

So the only way to have Emacs cover the entire screen without window
decorations is to use a font which fits?

If so, is there some way to override the character width/height? Since
I'm only displaying images, I wouldn't care about garbled text.

-David

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

David Engster writes:
> Eli Zaretskii writes:
>>> From: David Engster <deng@randomsample.de>
>>> Date: Sun, 09 Jun 2013 00:04:57 +0200
>>> 
>>> it seems I cannot resize the frame when the 'fullscreen' parameter
>>> is set to 'fullboth', which (I think) is the only way to get rid of
>>> the window decorations. Is this really the case or am I missing
>>> something?
>>
>> Yes, this is by design.
>
> So the only way to have Emacs cover the entire screen without window
> decorations is to use a font which fits?

Actually, even that does not seem to work. If I set the '8x16' font in
the new frame and then switch to fullscreen, it can show only 47 lines
instead of 48 on a 1366x768 display. What is taking up the space down
there?

-David

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

David Engster writes:
> David Engster writes:
>> Eli Zaretskii writes:
>>>> From: David Engster <deng@randomsample.de>
>>>> Date: Sun, 09 Jun 2013 00:04:57 +0200
>
>>>> 
>>>> it seems I cannot resize the frame when the 'fullscreen' parameter
>>>> is set to 'fullboth', which (I think) is the only way to get rid of
>>>> the window decorations. Is this really the case or am I missing
>>>> something?
>>>
>>> Yes, this is by design.
>>
>> So the only way to have Emacs cover the entire screen without window
>> decorations is to use a font which fits?
>
> Actually, even that does not seem to work. If I set the '8x16' font in
> the new frame and then switch to fullscreen, it can show only 47 lines
> instead of 48 on a 1366x768 display. What is taking up the space down
> there?

Aaah, it's the internal border. Setting

(internal-border-width . 0)

in the frame parameters will do the trick.

-David

Re: Emacs fullscreen and sizes in frame parameters

[Jan Djärv]

Hello.

Internal or external border width probably.

	Jan D.

9 jun 2013 kl. 09:24 skrev David Engster <deng@randomsample.de>:

> David Engster writes:
>> Eli Zaretskii writes:
>>>> From: David Engster <deng@randomsample.de>
>>>> Date: Sun, 09 Jun 2013 00:04:57 +0200
>>>> 
>>>> it seems I cannot resize the frame when the 'fullscreen' parameter
>>>> is set to 'fullboth', which (I think) is the only way to get rid of
>>>> the window decorations. Is this really the case or am I missing
>>>> something?
>>> 
>>> Yes, this is by design.
>> 
>> So the only way to have Emacs cover the entire screen without window
>> decorations is to use a font which fits?
> 
> Actually, even that does not seem to work. If I set the '8x16' font in
> the new frame and then switch to fullscreen, it can show only 47 lines
> instead of 48 on a 1366x768 display. What is taking up the space down
> there?
> 
> -David

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

Jan Djärv writes:
> Internal or external border width probably.

Yep. See my other mail 2 minutes before yours. :-)

And yes, I'm working on X11. So I'm now back at how to choose the right
font for a real fullscreen frame. I guess "5x8" should be OK for almost
all common resolutions, but I can't be sure. So the question remains if
I can somehow fake this... The optimum would be a fake font with 1 pixel
height. :-)

Thanks,
-David

Re: Emacs fullscreen and sizes in frame parameters

[chad]

On 09 Jun 2013, at 02:40, David Engster <deng@randomsample.de> wrote:

> And yes, I'm working on X11. So I'm now back at how to choose the right
> font for a real fullscreen frame. I guess "5x8" should be OK for almost
> all common resolutions, but I can't be sure. So the question remains if
> I can somehow fake this... The optimum would be a fake font with 1 pixel
> height. :-)

You might see if modern X11 systems still recognize the font `nil2'.

~Chad

Re: Emacs fullscreen and sizes in frame parameters

[Thien-Thi Nguyen]

() chad <yandros@MIT.EDU>
() Sun, 9 Jun 2013 05:47:26 -0700

   On 09 Jun 2013, at 02:40, David Engster <deng@randomsample.de> wrote:

   > And yes, I'm working on X11. So I'm now back at how to choose the right
   > font for a real fullscreen frame. I guess "5x8" should be OK for almost
   > all common resolutions, but I can't be sure. So the question remains if
   > I can somehow fake this... The optimum would be a fake font with 1 pixel
   > height. :-)

   You might see if modern X11 systems still recognize the font `nil2'.

a righteous font once spoke to me thus:
"make me your default, i'll give you no fuss!"
spake did i the incantations,
"make" did try the instantiations,
result?  eye-torture and mouth filled w/ cuss.

thi

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

chad writes:
> On 09 Jun 2013, at 02:40, David Engster <deng@randomsample.de> wrote:
>
>> And yes, I'm working on X11. So I'm now back at how to choose the right
>> font for a real fullscreen frame. I guess "5x8" should be OK for almost
>> all common resolutions, but I can't be sure. So the question remains if
>> I can somehow fake this... The optimum would be a fake font with 1 pixel
>> height. :-)
>
> You might see if modern X11 systems still recognize the font `nil2'.

Actually yes, nil2 is still there, but I cannot use it in Emacs for some
reason. 'xterm -fn nil2' works, and I see that nil2 is an alias for

-misc-nil-medium-r-normal--2-20-75-75-c-10-misc-fontspecific

but Emacs tells me

  'Font `nil2' is not defined'.

-David

Re: Emacs fullscreen and sizes in frame parameters

[David Engster]

David Engster writes:
> chad writes:
>> On 09 Jun 2013, at 02:40, David Engster <deng@randomsample.de> wrote:
>>
>>> And yes, I'm working on X11. So I'm now back at how to choose the right
>>> font for a real fullscreen frame. I guess "5x8" should be OK for almost
>>> all common resolutions, but I can't be sure. So the question remains if
>>> I can somehow fake this... The optimum would be a fake font with 1 pixel
>>> height. :-)
>>
>> You might see if modern X11 systems still recognize the font `nil2'.
>
> Actually yes, nil2 is still there, but I cannot use it in Emacs for some
> reason. 'xterm -fn nil2' works, and I see that nil2 is an alias for
>
> -misc-nil-medium-r-normal--2-20-75-75-c-10-misc-fontspecific
>
> but Emacs tells me
>
>   'Font `nil2' is not defined'.

I've found a good replacement by using a xft font with very small
height: "Bitstream Charter" with height '20' is 1 pixel wide and 4
pixels high. Everything below 11 makes Emacs segfault with a floating
point exception (should I submit a report about this? I think there was
already one, but I cannot find it).

The only thing still bothering me is the rightmost column that is
reserved for the truncation/continuation character. I already tried
setting it to 'zero-width' through glyphless-char-display, but that does
not work. Can I somehow reclaim the rightmost column, or is this fixed?

-David

Re: Emacs fullscreen and sizes in frame parameters

[Jan Djärv]

Hello.

9 jun 2013 kl. 00:04 skrev David Engster <deng@randomsample.de>:

> I'd like Emacs to display an image so that it spans the *entire* screen
> from top to bottom. That means: just the image, no window decorations or
> anything else.
> 
> I know that Emacs frames can only have pixel-sizes which are multiples
> of the character width and height. Still, I was hoping that I could
> achieve that by simply making the frame a bit larger. However, it seems
> I cannot resize the frame when the 'fullscreen' parameter is set to
> 'fullboth', which (I think) is the only way to get rid of the window
> decorations. Is this really the case or am I missing something?

You don't say what window system you are running, but for X at least, the window manager does not allow resizing of a fullscreen window.  This is kind of the point of having fullscreen windows, i.e. fixed size covering the screen.  For NS, it behaves the same.  I guess W32 does the same thing, but I don't know for sure.

	Jan D.

Re: Emacs fullscreen and sizes in frame parameters

[Eli Zaretskii]

> From: Jan Djärv <jan.h.d@swipnet.se>
> Date: Sun, 9 Jun 2013 08:55:52 +0200
> Cc: emacs-devel@gnu.org
> 
> You don't say what window system you are running, but for X at least, the window manager does not allow resizing of a fullscreen window.  This is kind of the point of having fullscreen windows, i.e. fixed size covering the screen.  For NS, it behaves the same.  I guess W32 does the same thing, but I don't know for sure.

W32 behaves the same.