[R] Artifacts in pdf() of image() (w/o comments)

Duncan Murdoch murdoch at stats.uwo.ca
Mon Aug 13 20:03:14 CEST 2007

On 8/13/2007 1:33 PM, Michael Kubovy wrote:
> Hi Duncan,
> I was trying to learn to remove the artifacts by setting the  
> parameters of the image so that anti-aliasing wouldn't produce them  
> (analogous to making sure that the screens of two halftone screen  
> process images are in register before combining them so as to avoid  
> Moiré patterns). So, I wasn't complaining; I was looking for  
> instruction. Since the image was computed with R, it's reasonable for  
> me to ask R experts to help me out of what I thought was caused by my  
> ineptitude. (Regarding your question, "If it wasn't a bug, why did it  
> bother you so much?"---there are many things that bother me that are  
> not bugs.)
> Moreover, I'm not opposed to complaining to Apple, once I have been  
> assured that I'm not reporting a bug where there's none.

Let me explain my point of view a bit more:

  - You saw ugly artifacts in a graph you produced.  That's a bug.  The 
question is, what caused it?
  - You rightly asked on R-help.  It might have been a bug in the way 
you were doing things, or a bug in R, or a bug in the way you were 
viewing the image.
  - It was demonstrated that this only appears in Preview, not in 
Acrobat Reader, so it's probably a bug there.

It's only at the last point that I object to what you did:  your 
question quoted below makes it look as though you think Apple's time is 
more valuable than ours.  I remind you that you paid for Preview, and 
you didn't pay for R.  Apple has a stronger obligation to help you than 
any of us do.  My experience with them (and with most other commercial 
software vendors) is that you'll get much worse help from them than from 
us --- but that doesn't mean you shouldn't try.  Perhaps when anyone 
searching for "Mac OSX Preview" on Google shows up a page full of 
unhandled bug reports they'll actually do something.

Duncan Murdoch

> On Aug 13, 2007, at 9:56 AM, Duncan Murdoch wrote:
>> On 8/13/2007 11:43 AM, Michael Kubovy wrote:
>>> But is it a bug? Can a program anti-alias text and line drawings  
>>> and  not bitmaps?
... [deletions] ...
>>>> An alternative to dropping Preview is to report the bug in it to   
>>>> Apple.  Apple has an online bug reporting web page somewhere; I   
>>>> haven't found them as helpful as R-help, but your mileage may vary.
>>>> Duncan Murdoch
... [the rest deleted] ...

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