🚀 go-pugleaf

>>>>> On 4 Oct 90 00:32:29 GMT, woody@chinacat.Unicom.COM (Woody Baker @ Eagle Signal) said:

> In article <LAMBERT.90Oct3110022@nankeen.spectrum.cs.unsw.oz.au>, I wrote:
>> >>>>> On 1 Oct 90 22:21:16 GMT, dsmith@applga.aa.cad.slb.com (J. Daniel Smith) said:

>> > I'm trying to print 1 pixel wide lines on a 300dpi PS printer.

>> Why not say "0 setlinewidth"?
> Because as has been pointed out before, 0 setlinewidth is not guaranteed to
> produce a 1 pixel wide line.  setting it to .12 is supposed to explicitly
> do that.

Huh?  The Red Book says that a line width of 0 produces a line one
device pixel wide.  If it doesn't then there is something wrong with
the implementation of PostScript on your printer.  I haven't tried it
that much, but it has worked whenever I've tried it.  You can draw a one
pixel wide line easily and very quickly using Bresenham's algorithm so
there aren't any excuses for an implementation that doesn't get it
right.

> A lot of times the problems with wide lines can be traced to
> rounding problems.  As I understand it, you can round up or down
> to .25, 0 .5.  Since any dot touched by a line gets filled in, in certain
> roungings, you will have problems.  This seems to occur when you have
> rounded such that you are straddling  the boundry between 2 ajacent
> rows of pixels. 


Yes, I can see how this can happen.  But if a line width of 0 gives
you a line two pixels wide, I don't see how a line width of 0.12 could
make it narrower.

Tim