[texhax] TeX -> PostScript, but in a resolution-independent manner

Randolph J. Herber herber at dcdrjh.fnal.gov
Wed Jun 4 19:02:39 CEST 2003

The following header lines retained to effect attribution:
|Date: Wed, 04 Jun 2003 20:16:59 +0200
|From: zsdc <zsdc at wp.pl>
|Subject: Re: [texhax] TeX -> PostScript, but in a resolution-independent manner
|To: Petr Sojka <sojka at informatics.muni.cz>
|Cc: texhax <texhax at tug.org>
|	<mailto:texhax-request at tug.org?subject=subscribe>
|	<mailto:texhax-request at tug.org?subject=unsubscribe>

|Petr Sojka wrote:


|Thanks for the link. But the more I read about it, I really start to
|getting confused... Are the scalable fonts always better than the bitmap
|fonts, or maybe I was wrong? Because from these tests it's not so
|obvious for me.

	I opine that the proper statement is that scalable or outline
	fonts, when actually displayed or printered become bitmap fonts.

	If the bitmap fonts match the resolution of the display or
	printing device and the bitmap pixels are aligned with the
	display or printer pixels (there is PostScript code to cause
	such an alignment; the dvips prologue contains such code),
	hen there ought not be any difference between the appearance
	of a bitmap font and a outline or scalable font.  If the
	printer or display is capable of grayscale or color at a
	single pixel, then those devices can use anti-aliasing
	techniques to achieve the effect of higher resolution.
	Most such printers and displays (and PostScript language
	provides for such capacities), if presented with a bit-map
	at an integer multiple of the device's resolution, can do
	averaging of the subpixels and thereby achieve an anti-
	aliasing effect directly.

	One of the parameters that can be given to dvips is the
	resolution of printer or display device so that dvips can
	use the correct font set or trigger the proper font
	generation.  As most printers work at 300 dpi, 600 dpi,
	1200 dpi, 1270 dpi (50dpmm), 1440 dpi or 2540 dpi (100
	dpmm), it is common to find pre-generated font sets at
	those resolutions.  A common mistake is to use a 300dpi
	font on a 1200 dpi printer, in that case, you have reduced
	it to being in effect a 300 dpi printer (although, a few
	printers will estimate where the letter edges should be
	and smooth them to the printer's actual capacity; but,
	that is seldom as good as using the proper font set).



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Randolph J. Herber, herber at fnal.gov, +1 630 840 2966, CD/CDFTF PK-149F,
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