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

[Joris Meys]

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
>
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>



-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

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