[Rd] readPNG gives warnings and doesn't execute sample code from help files

[Ben Bolker]

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On 02/15/2011 08:44 AM, Joris Meys wrote:
> Sorry, correction. X11() is not supposed to do that. So on Windows,
> per-pixel alpha is no option apparently. Any chance this will be
> implemented in the future?
> 
> Cheers
> Joris
> 
> PS : also thx to Simon for his helpful answer earlier.

  Hmmm.

  I think your best bet would be
http://cran.r-project.org/web/packages/Cairo/index.html ... ?


> 
> On Tue, Feb 15, 2011 at 2:40 PM, Joris Meys <jorismeys at gmail.com> wrote:
>> Thx again for your answer. I've tried X11() - which is supposed to
>> support alpha per pixel as well, but on Windows that's still no avail.
>> So basically, on Windows I can forget about alpha?
>>
>> Cheers
>> Jors
>>
>> On Tue, Feb 15, 2011 at 2:20 PM, Ben Bolker <bbolker at gmail.com> wrote:
>>> Joris Meys <jorismeys <at> gmail.com> writes:
>>>
>>>>
>>>> I believed the standard plotting device on R in 2.12.1 would support
>>>> per-pixel alpha. It does support alpha, as
>>>>
>>>>  plot(1:2,type="l")
>>>>  polygon(c(1,1,2,2),c(1,2,2,1),col=rgb(60,100,60,60,maxColorValue=255))
>>>>
>>>> plots correctly. Which device should I use then?
>>>
>>> See
>>>
>>> http://developer.r-project.org/Raster/raster-RFC.html
>>>
>>> (near the bottom of the page, where it explains that the
>>> Windows device supports alpha but not per-pixel alpha ...)
>>>
>>>  cheers
>>>    Ben Bolker
>>>
>>> ______________________________________________
>>> R-devel at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>>
>>
>>
>>
>> --
>> Joris Meys
>> Statistical consultant
>>
>> Ghent University
>> Faculty of Bioscience Engineering
>> Department of Applied mathematics, biometrics and process control
>>
>> tel : +32 9 264 59 87
>> Joris.Meys at Ugent.be
>> -------------------------------
>> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>>
> 
> 
> 

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