From bbolker at gmail.com  Tue Dec 14 19:20:24 2010
From: bbolker at gmail.com (Ben Bolker)
Date: Tue, 14 Dec 2010 13:20:24 -0500
Subject: [Rd] postscript failure manifests in plot.TukeyHSD
In-Reply-To: <4D07B46C.8030808@ucalgary.ca>
References: <C92D60FB.142C5%jari.oksanen@oulu.fi>
	<loom.20101214T174819-887@post.gmane.org>
	<4D07B46C.8030808@ucalgary.ca>
Message-ID: <4D07B568.6000505@gmail.com>

On 10-12-14 01:16 PM, Peter Ehlers wrote:
> On 2010-12-14 09:27, Ben Bolker wrote:
>> Jari Oksanen<jari.oksanen<at>  oulu.fi>  writes:
>>
>>>
>>> Hello R Developers,
>>>
>>> Dear R-developers,
>>>
>>> I ran some standard tests with currently (today morning) compiled R
>>> release
>>> candidate in Linux R 2.12.1 RC (2010-12-13 r53843). Some of these
>>> tests used
>>> plot.TukeyHSD function. This worked OK on the screen (X11 device), but
>>> PostScript file could not be rendered. The following example had the
>>> problem
>>> with me:
>>>
>>> postscript(file="tukeyplot.ps")
>>> example(plot.TukeyHSD)
>>> dev.off()
>>>
>>> I couldn't view the resulting file with evince in Linux nor in the
>>> standard
>>> Preview in MacOS. When I compared the generated "tukeyplot.ps" to the
>>> same
>>> file generated with an older R in my Mac, I found one difference:
>>>
>>> $ diff -U2 oldtukeyplot.ps /Volumes/TIKKU/tukeyplot.ps
>>> --- oldtukeyplot.ps    2010-12-14 12:06:07.000000000 +0200
>>> +++ /Volumes/TIKKU/tukeyplot.ps    2010-12-14 12:13:32.000000000 +0200
>>> @@ -172,5 +172,5 @@
>>>   0 setgray
>>>   0.00 setlinewidth
>>> -[ 3.00 5.00] 0 setdash
>>> +[ 0.00 0.00] 0 setdash
>>>   np
>>>   660.06 91.44 m
>>>
>>> Editing the changed line to its old value "[ 3.00 5.00] 0 setdash" also
>>> fixed the problem both in Linux and in Mac. Evidently something has
>>> changed,
>>> and probably somewhere else than in plot.TukeyHSD (which hasn't changed
>>> since r51093 in trunk and never in R-2-12-branch). I know nothing about
>>> PostScript so that I cannot say anything more (and I know viewers can
>>> fail
>>> with standard conforming PostScript but it is a bit disconcerting
>>> that two
>>> viewers fail when they worked earlier).
>>
>>    I must really be avoiding work today ...
>>
>>    I can diagnose this (I think) but don't know the best way to
>> solve it.
>>
>>    At this point, line widths on PDF devices were allowed to be<1.
>>
>> ==========
>> r52180 | murrell | 2010-06-02 23:20:33 -0400 (Wed, 02 Jun 2010) | 1 line
>> Changed paths:
>>     M /trunk/NEWS
>>     M /trunk/src/library/grDevices/src/devPS.c
>>
>> allow lwd less than 1 on PDF device
>> ==========
>>
>>    The behavior of PDF devices (by experiment) is to draw a 0-width
>> line as 1 pixel wide, at whatever resolution is currently being
>> rendered.  On the other hand, 0-width lines appear to break PostScript.
>> (with the Linux viewer 'evince' I get warnings about "rangecheck -15"
>> when trying to view such a file).
>>
>>    plot.TukeyHSD  contains the lines
>>
>> abline(h = yvals, lty = 1, lwd = 0, col = "lightgray")
>> abline(v = 0, lty = 2, lwd = 0, ...)
>>
>>    which are presumably meant to render minimum-width lines.
>>
>>    I don't know whether it makes more sense to (1) change plot.TukeyHSD
>> to use positive widths (although that may not help: I tried setting
>> lwd=1e-5 and got the line widths rounded to 0 in the PostScript file);
>> (2) change the postscript driver to *not* allow line widths<  1 (i.e.,
>> distinguish between PS and PDF and revert to the pre-r52180 behaviour
>> for PS only).
>>
>>    On reflection #2 seems to make more sense, but digging through devPS.c
>> it's not immediately obvious to me where/how in SetLineStyle or
>> PostScriptSetLineTexture one can tell whether the current driver
>> is PS or PDF ...
>>
> That may not do it. I find the same problem (fixed by
> Jari's replacement of [ 0.00 0.00] with [ 3.00 5.00];
> haven't tried anything else yet) when I use pdf()
> instead of postscript().
> This is on Vista.
> 
> Peter Ehlers

  With PDF, I get "invalid value for a dash setting" from evince --
perhaps the dash lengths are being set relative to the line width?
(Could investigate but had better continue with other things ...)

  Ben Bolker



[Rd] postscript failure manifests in plot.TukeyHSD
Ben Bolker