[Rd] Macintosh Transperancy (PR#11511)

Mon May 26 23:21:55 CEST 2008

see below

On May 24, 2008, at 6:07 PM, Bradley Vance wrote:

> Simon,
> 	The bug is that the point that's being plotted is a single point, not
> a combination of two points, one that's just the outline, and one
> that's just the fill.  It also doesn't look like we'd expect when
> you're debugging a plot.  For example, let's say I create a plot, and
> notice that I can't see some of the points (due to other points being
> drawn on top of them).  So I decide to make them transparent, so you
> can see where points over-lay each other, and the relative size/ 
> colors/
> etc of the over-layed points.  Now, rather than just changing the
> opacity of the points/colors I see, I'm adding in another color to
> each point where outline and background meet, making the plot more
> confusing than it needs to be...
> 	In looking at the documentation for bg in points (plot says to look
> at points for bg) it says
> bg
> background (fill) color for the open plot symbols given by pch=21:25.
> and the way it is now, the color is not a fill (ie - inside the lines)
> - it's super-imposed over part of the line.
> 	Also, there's the fact that it does something different on different
> systems.  When I do the same thing at work on a Linux box (we don't
> have R.2.7 yet, we use mostly R2.4 but I've tried it on R2.6, and we
> don't have Quartz, but I did output to PDF), it looks like a single
> point whose colors were made transparent, and not a point made of two
> overlapping transparent parts.

Brad, you seem to be missing what people are saying. There has been  
major changes to the graphics system in R-2.7 on all systems. Se for  
example the NEWS file on CRAN, that has an entire section on Graphic  
Devices. One of the changes have indeed been in how it handles  
transparency, again across platforms.

The fact that you are testing on R-2.6.0 on Linux is beside the point.  
The major difference is that you are using R-2.6 and not that you are  
using Linux. If you don't have access to R-2.7 on Linux it is fine,  
but in the rest of your post you should replace "Linux" with "Old,  
outdated version of R".

Simon is saying that for R-2.7, this works exactly the same across all  
platforms and you have not said anything to contradict him in this.

This may be a reasonable wishlist item, I do not really have an  
opinion on this. But it is really an R-devel issue, not a Mac OS X  
issue.

Kasper

>
> 	As I implied in my original ticket, I'd like to be able to choose
> whether to have it look the way it does now on the mac, and the way it
> does on Linux.  This might actually be something that needs to be
> addressed further by the core team, as that opacity is planning to be
> added for X11() for the next revision (and hopefully, will work into
> PNG and other device types that can support it)...
> 	Perhaps the best way to implement the options/choices/etc is to add a
> separate alpha/opacity/whatever options that would control the opacity
> of each object it plots.  Thus, if you define an opacity to either col
> or bg, it would work the way it does on the Mac (ie - the colors are
> opaque and can thus you can see the other point-color through the top
> one).  However, if you have a point-opacity defined, the entire point
> will get the opacity, the way it is currently done on Linux.
> 	Or, you can just say that in order to get it look the way that it
> currently does on the mac, you need to plot each point twice, once
> with no bg, and once with no line...
>
> 	Also, I don't think this is a critical bug.  It's just something I
> noticed that behaves differently on what I have at work (Linux) and
> what I have at home (mac).  I'm impressed with R, and am thinking of
> getting more involved in the r-project community, so figured I'd start
> with something I noticed was different across platforms...
>
> On May 24, 2008, at 6:17 PM, Simon Urbanek wrote:
>
>> Brad,
>>
>> can you, please, let us know what is the "bug" here? If you paint
>> semi-transparent line over the same filled shape (same vertices),
>> clearly half of the line will be inside and and half outside of the
>> shape, so each part will have a different color - that is the whole
>> point of semi-transparency. Therefore I fail to see any bug or
>> unexpected behavior here.
>>
>> Cheers,
>> Simon
>>
>>
>> On May 24, 2008, at 10:55 AM, brdvance at gmail.com wrote:
>>
>>> Full_Name: Brad Vance
>>> Version: 2.7.0
>>> OS: 10.5.2
>>> Submission from: (NULL) (71.123.195.202)
>>>
>>>
>>> Problem : When drawing transperant points with lines thick-
>>> lines(lwd>1) + fill
>>> (pch=21-25), it looks like the line is transperantly overlayed over
>>> the fill,
>>> making it look like 2-lines surround the fill (each a different
>>> color).  I
>>> actually think that this is a nice OPTIONAL way to draw the points
>>> (even as
>>> default), but since I could not discover how to turn it off, I
>>> decided to issue
>>> the ticket.  In this option can see on the default-quartz device as
>>> well as
>>> PDF-device.
>>>
>>> Solution : Have the entire point-object designed/drawn as if there  
>>> is
>>> no-transparency, then make the composite object transparent.
>>> Optionally figure
>>> out an option to determine whether to apply transperancy as a group
>>> (to the
>>> entire object) or separately (as it is now).
>>>
>>> Code :
>>>> df <- data.frame(X=rnorm(50),Y=rnorm(50))
>>>> plot
>>>> (X
>>>> ~
>>>> Y
>>>> ,data
>>>> =
>>>> df 
>>>> ,pch=c(21,22,23,24,25),cex=5,col="#00FF0055",bg="#FF000055",lwd=6)
>>>
>>> Thanks,
>>> -Brad Vance
>>>
>>> ______________________________________________
>>> R-devel at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>>
>>>
>>
>
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