- From: Ken Stacey <ken@svgmaker.com>
- Date: Wed, 08 Jan 2014 04:03:08 +1000
- To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>, www-svg@w3.org
Dr. Olaf, I agree with much of what you say about absolute units as my main focus for many years has been printing with SVG. Absolute units are essential for many types of documents. Dr. Olaf Hoffmann wrote: > Well, if an author provides an SVG document, > ... > and specifies width and height in mm and notes in the text, that the > graphics shows the original size, obviously the presentation is > broken, if a mm is not presented as a mm. > The user-agent clearly fails, if this is presented with the wrong > size. If this happens in an online shop, the consequences can result > in a disaster or at least in a frustrating experience ;o) The frustrating fact for many user agents is that there is no reliable way (at least on Windows) to determine the real-world pixel size of every monitor. I believe that some monitors do reveal their physical size (Extended display identification data) to drivers etc, but most do not. (Windows) OS settings are available to set a "soft" dpi resolution for the monitor. This setting could be changed to a measured value which matches the monitor, but most often, it is used to adjust the size of text and graphics depending on the eyesight of the user. When the user agent asks the OS what the screen resolution is, the returned value is almost never the real value. This doesn't just affect SVG and browsers. Open a word processor document at 1:1 zoom and compare the printed text size (or paper size) against the monitor. Connect your laptop to your widescreen TV and check against that. Knowing this about Windows, I would never take a ruler to a monitor and rely on an absolute measurement. Maybe the situation will improve. I think that this history of unreliable/unknown pixel sizes is responsible for the use of a nominal value. Now that nominal value has a history. Not sure if that is good or bad - possibly a bit of both. Ken
Received on Tuesday, 7 January 2014 18:03:38 UTC