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Re: Making pt a non-physical unit

From: Ambrose LI <ambrose.li@gmail.com>
Date: Tue, 5 Jan 2010 11:58:26 -0500
Message-ID: <af2cae771001050858w6386226ak37df999451bff4a5@mail.gmail.com>
To: Boris Zbarsky <bzbarsky@mit.edu>
Cc: rfink@readableweb.com, robert@ocallahan.org, www-style <www-style@w3.org>
2010/1/5 Boris Zbarsky <bzbarsky@mit.edu>:
> On 1/5/10 9:56 AM, Richard Fink wrote:
>> How is this even possible without knowing the actual physical dimensions
>> of the display?
> Whatever made you think these are unknown?  They're certainly known to the
> OS (e.g. watching debug output from an X server starting up shows various
> information about the display including its self-reported physical size; in
> my measuring with a ruler these sizes are pretty much correct).

As a user, I don't believe the OS knows what the true size and/or
resolution of the display. IIRC, when Apple's X server still gave us
two screens (:0.0 and :0.1) for my dual head setup (:0.0 being Apple's
own notebook LCD so theoretically its size must be known, and :0.1
being an external LCD monitor), the numbers didn't look quite right.
But now that it gives me just one merged display, the numbers clearly
must be wrong, because I know that the two screens do have different
resolution. Yet the X server reports that the single X display has
some single resolution. The existence of xinerama alone shows that
querying the X server does not guarantee a correct resolution and/or

Moreover, as far as I can see, there are no programs, on any OS, which
has a ‘View|Actual size’ command that actually enables itself to
display anything in actual size. (Maybe they did very long time ago
when all Macs were all 72dpi.) This alone makes me believe that the OS
really has no idea of the actual resolution of any display.

Received on Tuesday, 5 January 2010 16:58:59 UTC

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