Todd Fahrner wrote: [sorry I'm entering this late] > " If you are looking for a new definition for the reference pixel, > perhaps, like DSSSL and early XSL, CSS lengths could be based on the SI > meter? Or are inches becoming a U.N. recommendation? :-) > > By my reading of CSS1, the "real" suggested reference pixel is a degree of > visual angle. The conversion to inches (1/90") merely provides an example > of what this works out to at arm's length. Wonder if Hakon or Bert can > comment. Yes, the motivation was to establish the pixel unit as a visual angle instead of tying it up to a certain device/resolution or other things that might change over time. The CSS1 spec uses a 90dpi example since that's a close to the average number a 28 inch arm since that's roughly how long the average arm is. Now, by twisting arms or bying new machinery, thees numbers can change significantly but the visual angle shouldn't. [In an earlier message Todd wrote] > 2. The 1996 CSS1 standard suggests a 1/90" value for a "reference pixel", > extrapolated from a visual angle of 0.0227 degrees visual angle at arms > nlength. UAs are expected to scale pixels appropriately if the physical > resolution is known to vary significantly from this value. A 1/90" > reference pixel would suggest a rasterization of 12pt into 15px, rather > than 16. Now you're using the "reference pixel" for something it wasn't designed to do. It was designed to determine how to interpret a CSS pixel value (e.g. "10px") into a device-dependent pixel value. It was not designed to determine how to interpret a non-pixel value (e.g. "12pt") into a device-dependent pixel value. -h&kon H å k o n W i u m L i e howcome@w3.org http://www.w3.org/people/howcome World W i d e Web ConsortiumReceived on Sunday, 3 January 1999 19:08:38 GMT
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