Default font size in gnome

[Chris Cheney]

On Sat, 2009-02-28 at 12:38 +0100, Markus Hitter wrote:
> This is likely all true, but with resolution independent rendering,  
> it no longer applies. In the future, "px" is just a measurement unit,  
> just like "in" or "mm". Once the software gets this, it's perfectly  
> fine for web developers to ask for a "12pt" font. It just won't be  
> rendered with characters 12 screen pixel high, but with this value,  
> divided/multiplied with the screen dpi.
> 
> I can understand this is difficult to get swallowed. For 40 (or more)  
> years now, the rule was 1 pixel = 1 dot on the screen. A picture,  
> 100px x 100px in size used to use exactly 100 x 100 dots on screen.  
> Now, this is no longer true.
> 
> To stir the mix additionally, there are many pieces of software  
> respecting resolution independent rendering and many others not.  
> Picture viewers still map one picture pixel to one dot on screen and  
> call this "100%". Font/text displying tools still shortcut rendering  
> engines and draw a 12pt font with 12-dot-on-screen character glyphs.  
> Some software considers 72 dpi screens (Macintosh monitors were  
> produced many years this way) as "standard", others won't work with  
> anything but a 96 dpi screen (Windows XP default setting). This makes  
> comparisons so difficult.
> 
> My personal hope is, this dust settles once people get used to set  
> their screen dpi just right: it is a measurable fact.
> 
> Then, they will start complaining a 12 px font is waaay to big for  
> phone screens ;-)
> 
> 
> MarKus
> 
> 
> P.S.: There's no real need for an additional measurement unit besides  
> mm and in, so I'd actually prefer to see "px" going away entirely.  
> What a dream!

Agreed that px should go away entirely in HTML.

However, it seems you have gotten several things confused.

Pt is point which was defined long before computers came into wide use.
It was finally officially defined as 1/72 of an inch in 1959 but had
been in that general range of size since at least the 1700s.

Px means pixel which is a picture element and is an abomination that it
was ever allowed into the HTML specification at all. 1 pixel definitely
means 1 picture element (dot) on the screen. That is where the word
pixel comes from. Redefining pixel to mean something else instead of
just using Pt properly would be crazy. Also where is a 100x100 image not
displayed as such? Only if you set zoom level to something other than
100% does this normally happen. Many (most?) image formats don't even
have the concept of DPI or image size in inches. Additionally if you
want 100% to always mean the images "size" you would need some other
terminology for displaying the full image data. For most uses other than
publishing having a size set for an image is useless since an image
doesn't really have an inherent DPI, it is scaled to fit whatever medium
you want it on. A 12MP image could just as easily be printed onto a 6x4
or 30x20 page. However, in cases where the image has DPI/size
information a publishing program should take that into account.
Actually, it would also be useful for web browsers to use this
information so that developers could include higher resolution images
that are scaled to fit the size they want to have displayed. Then web
browsers could also have a user adjustable scaling factor that could be
applied to an entire page in cases where smaller screens need to view an
entire page.

I'm not sure the last time general DPI has been 72 DPI, at least on
Windows computers (or Macs afaik) for at least the past decade they have
been kept their DPI settting set to 96 DPI. The last time a monitor was
72 DPI was probably when 15" CRT (13.8" viewable) were commonly at
800x600 resolution. My computer from 15 years ago was even higher than
that running at 1024x768 on a 15" CRT (93 DPI).

The main issue here is that operating systems are broken so a Web
designer can't use a point based font and expect it to look the same
everywhere, which it should. So sometimes they end up using pixel based
sizes because of that reason, and in some cases they use pixel based
sizes just from not knowing any better. Once there are enough operating
systems that work properly hopefully it will pressure Microsoft into
properly fixing this issue in Windows. Until then it will be hard to
make a browser that will display properly on all platforms, unless there
is some way for a browser to query the true DPI of a screen on Windows?

Chris