--- Pierre Abbat <[EMAIL PROTECTED]> wrote:
> On Tuesday 20 May 2008 09:55, Patrick Moore wrote:
> > It seems that today DPI for resolution is used worldwide by the computer
> > industry, including printers. My googling in the last day has turned up an
> > alternative, simply to specify pixels in micrometers. However, I fear that
> > this alternative will require an ISO standard and decades before it becomes
> > widely adopted. See these links:
> > <http://www.iol.ie/~sob/tm/index.xhtml>
> > <http://www.cl.cam.ac.uk/~mgk25/metric-typo>
> > <http://en.wikipedia.org/wiki/Metric_typographic_units>
>
> There are four separate issues here: the size of a printed pixel, the unit
> used by PostScript, the dimension of a letter to use as the font size, and
> the set of font sizes available in some software. For which dimension to use,
> see the links.
>
> Plotters are, and have been since I was a kid, made with a resolution that is
> a round submultiple of 0.1 mm, typically 0.025 mm. I don't know if the
> physical resolution of inkjet plotters is a submultiple of 0.1 mm, but I do
> know that the HPGL driver at my office, used with the last version of AutoCAD
> that was available for SCO, expresses distances in 25 µm units. This means
> that both inches and millimeters are expressible as integers, but the point
> is not.
>
> PostScript is perfectly capable of scaling by arbitrary factors, but if you
> want to make a document in millimeters, you have to specify it at the top of
> each page. To fix this, Adobe and whoever else writes PostScript-handling
> software have to do three things:
> 1. Add a version of the PS-Adobe header that says that a document is metric.
> 2. Add a flag to the PostScript interpreter (which ignores DSC) to specify
> millimeters.
> 3. Modify the software to recognize the new header, so that BoundingBox
> values
> in millimeters are computed correctly.
>
> For a set of font sizes, I suggest using the musical scale. Many ratios in it
> are close to ratios of small integers, and the ratio between two paper sizes
> such as A1 and B1 (before rounding to millimeters) is three half steps. As
> PostScript can scale by arbitrary ratios, this can be implemented
> independently of printer resolution.
An odd suggestion! Dealing with that system doesn't sound very appealing to
me. Factors of
2^(1/12)? That's even worse than working with feet, yards, rods, and so forth.
Why not just get
rid of the whole concept of a fixed set of font sizes (seriously, who still
uses mechanical type?)
and just let me tell the computer that I want my letters to be, say, 8.4 mm
tall? That would be
ideal to me.
