Grub2 theme bug with relative numeric values for boot_menu?

Grub2 theme bug with relative numeric values for boot_menu?

[John Hupp]

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I'm trying to make my theme completely resolution-independent.  You can 
see a current screen shot at Post your Grub 2 Themes 
<http://ubuntuforums.org/showthread.php?t=1823915&page=14&p=13031738#post13031738>

Grub responded well to % values for the numeric values in the progress 
bar and labels.  Also OK with %'s for boot_menu properties top, left, 
height, width.

But I'm getting bad behavior with item_height and the other properties.  
For a 1024x768 grub display and an original setting of item_height = 26, 
I can't get equivalent output unless I set item_height = 27%

So item_height seems to be referencing a parent with a height of about 
96, rather than 768.

This is in a VMWare Player environment running Lubuntu 14.04.

Is this a known problem, or is there an explanation/workaround?

(I also realized as I got into this that I will run into a problem with 
different aspect ratios, so other than creating at least two themes for 
the commonest aspect ratios, I'd be interested in a tip there as well if 
there is a solution.)

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Re: Grub2 theme bug with relative numeric values for boot_menu?

[Andrey Borzenkov]

В Mon, 26 May 2014 18:19:23 -0400
John Hupp <grub-dev@prpcompany.com> пишет:

> I'm trying to make my theme completely resolution-independent.  You can 
> see a current screen shot at Post your Grub 2 Themes 
> <http://ubuntuforums.org/showthread.php?t=1823915&page=14&p=13031738#post13031738>
> 

Pictures are blocked for guests.

> Grub responded well to % values for the numeric values in the progress 
> bar and labels.  Also OK with %'s for boot_menu properties top, left, 
> height, width.
> 
> But I'm getting bad behavior with item_height and the other properties.  
> For a 1024x768 grub display and an original setting of item_height = 26, 
> I can't get equivalent output unless I set item_height = 27%
> 

These properties do not even understand proportional units. If you are
using modified grub which adds support for it, please post patch,
otherwise it is impossible to make any useful comment.

> So item_height seems to be referencing a parent with a height of about 
> 96, rather than 768.
> 
> This is in a VMWare Player environment running Lubuntu 14.04.
> 
> Is this a known problem, or is there an explanation/workaround?
> 
> (I also realized as I got into this that I will run into a problem with 
> different aspect ratios, so other than creating at least two themes for 
> the commonest aspect ratios, I'd be interested in a tip there as well if 
> there is a solution.)

Re: Grub2 theme bug with relative numeric values for boot_menu?

[John Hupp]

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On 6/2/2014 9:59 AM, Andrey Borzenkov wrote:
> В Mon, 26 May 2014 18:19:23 -0400
> John Hupp <grub-dev@prpcompany.com> пишет:
>
>> I'm trying to make my theme completely resolution-independent.  You can
>> see a current screen shot at Post your Grub 2 Themes
>> <http://ubuntuforums.org/showthread.php?t=1823915&page=14&p=13031738#post13031738>
>>
> Pictures are blocked for guests.

Thanks for replying.

Here it is:

>
>> Grub responded well to % values for the numeric values in the progress
>> bar and labels.  Also OK with %'s for boot_menu properties top, left,
>> height, width.
>>
>> But I'm getting bad behavior with item_height and the other properties.
>> For a 1024x768 grub display and an original setting of item_height = 26,
>> I can't get equivalent output unless I set item_height = 27%
>>
> These properties do not even understand proportional units. If you are
> using modified grub which adds support for it, please post patch,
> otherwise it is impossible to make any useful comment.

I did not know that these properties do not understand proportional 
units.  The documentation indicated that ALL numeric property values 
could be absolute or relative/proportional.  Regardless of that, I 
realized as I was working on it that unless relative value support 
extended to decimal values and not just integers, then I could not 
achieve what I was aiming for, because small values like item height, 
padding, etc., do not convert very precisely to integer percentages.

But even if there were support for decimal relative values, I also 
realized that I would have a problem getting equivalent displays under 
different screen aspect ratios.  This is especially true for icon height 
and width: an icon that is square under one aspect ratio would be 
rectangular under another.

So under the current grub scheme, we can make themes that are somewhat 
resolution-independent: the menu footprint and location, and label and 
progress bar locations will scale, but the menu items' properties must 
be absolute, meaning that they will be relatively large on some displays 
and small on others.  And I grant that this problem may be difficult to 
solve without adding a lot of code.

>
>> So item_height seems to be referencing a parent with a height of about
>> 96, rather than 768.
>>
>> This is in a VMWare Player environment running Lubuntu 14.04.
>>
>> Is this a known problem, or is there an explanation/workaround?
>>
>> (I also realized as I got into this that I will run into a problem with
>> different aspect ratios, so other than creating at least two themes for
>> the commonest aspect ratios, I'd be interested in a tip there as well if
>> there is a solution.)


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Re: Grub2 theme bug with relative numeric values for boot_menu?

[Andrey Borzenkov]

В Mon, 02 Jun 2014 12:06:03 -0400
John Hupp <grub-dev@prpcompany.com> пишет:

> >
> >> Grub responded well to % values for the numeric values in the progress
> >> bar and labels.  Also OK with %'s for boot_menu properties top, left,
> >> height, width.
> >>
> >> But I'm getting bad behavior with item_height and the other properties.
> >> For a 1024x768 grub display and an original setting of item_height = 26,
> >> I can't get equivalent output unless I set item_height = 27%
> >>
> > These properties do not even understand proportional units. If you are
> > using modified grub which adds support for it, please post patch,
> > otherwise it is impossible to make any useful comment.
> 
> I did not know that these properties do not understand proportional 
> units.  The documentation indicated that ALL numeric property values 
> could be absolute or relative/proportional.

I re-checked grub2 manual for 2.00 and it explicitly says that
item_height is in pixel; it lists several properties for which support
for proportional units is explicitly stated. So either you are using
different manual (coming from your distribution?) or probably
misunderstood it. In which case it would help if you suggested
corrections that make it more clear.

I guess that grub simply ignored '%' and interpreted value as absolute
one.

Or your grub does support proportional units for item_height indeed,
then it is distribution-specific patch.