Re: [css3-fonts] font-size-adjust auto issue

Le Mer 21 août 2013 9:36, John Daggett a écrit :
>
> Gérard Talbot wrote:
>
>> I think I understand what Vladimir wanted to say. Generally
>> speaking, most of the time, the 'auto' keyword refers to default
>> value, the per se value or initial value. Not in this case. And so,
>> the use of auto is a bit counter-intuitive from a CSS perspective.
>>
>> body
>> {
>> font-family: "Times New Roman";
>> font-size-adjust: auto;
>> }
>>
>> really does nothing. If "Times New Roman" is an available and
>> installed font, then 'font-size-adjust: auto;' does nothing,
>> accomplishes nothing.
>
> It's hard to know what "does nothing" here means.  The 'auto' value
> means use the aspect value of the *default font*.

John,

This is what I missed in previous posts. I'm sorry. Thanks for emphasizing
this for me.

> If that's
> Liberation Sans for your browser, then whether it "does nothing" or
> not depends upon whether the aspect value of Times New Roman is
> different or not.  If it is, then this *will* do something.

Thanks for emphasizing this for me.


> In this case:
>
>   a  = aspect value of default font (e.g. Liberation Sans)
>   a' = aspect value of Times New Roman
>
>> Let's take your example here:
>>
>>    font-family: Futura, Verdana;
>>    font-size-adjust: auto;
>>    font-size: 20px;
>>
>> I do not have Futura font installed on my Linux (debian-based) system. I
>> do not have Verdana installed either.
>
> In this situation, no change will occur.  If neither Futura or Verdana
> is available, then the default font will be used.  Hence both (a) and
> (a') will be the same, they will both be the aspect value of the
> default font.
>
>> The only way I can see this 'auto' value working would be if the
>> user agent has a list (or map) of font names with correspondent
>> aspect value, especially font names of fonts that are not installed
>> on the user's operating system.
>
> No, 'auto' simply sets the font-size-adjust value to the aspect value
> of the default font.  An author tunes the font size to what they want
> with the set of fonts they have, then let's font-size-adjust assure
> that in situations where fallback fonts are used instead that the text
> has roughly the same readability.
>
>> ~$ fc-match Futura
>> DejaVuSans.ttf: "DejaVu Sans" "Book"
>>
>> So, my system will resort to "DejaVu Sans" font instead which has an
>> aspect value of 0.55. In such situation, what would be the value of a
>> variable in the c  =  ( a / a' ) s equation ?
>
> Precisely as noted above, both (a) and (a') would be 0.55 and no size
> adjustment would occur.
>
> Cheers,
>
> John Daggett

Thank you for your posted message,

Gérard
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Received on Wednesday, 21 August 2013 15:39:17 UTC