Plot Rect Transparency

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Plot Rect Transparency

reichmaj
R-Help

 

Is there a way to make a rectangle transparent (alpha=0.1??)

 

  plot(c(100, 200), c(300, 450), type= "n", xlab = "", ylab = "")

   rect(110, 300, 175, 350, density = 5, border = "red")

 

Can't figure out how to take the changepoint function results and plot in
ggplot2 so I can just simply add rectangles to the plot function, but I need
to make transparent and there doesn't seem to be an alpha option.

 

Jeff


        [[alternative HTML version deleted]]

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Re: Plot Rect Transparency

Duncan Murdoch-2
On 28/06/2018 5:29 PM, Jeff Reichman wrote:

> R-Help
>
>  
>
> Is there a way to make a rectangle transparent (alpha=0.1??)
>
>  
>
>    plot(c(100, 200), c(300, 450), type= "n", xlab = "", ylab = "")
>
>     rect(110, 300, 175, 350, density = 5, border = "red")
>
>  
>
> Can't figure out how to take the changepoint function results and plot in
> ggplot2 so I can just simply add rectangles to the plot function, but I need
> to make transparent and there doesn't seem to be an alpha option.

Alpha is part of the colour spec.  For example,

rect(110, 300, 175, 350, density = 5, border = rgb("red")


rect(110, 300, 175, 350, density = 5, border = rgb(red=1, green=0,
blue=0, alpha=0.1))

I'm not sure what is the quickest way to work out the rgb values for a
named colour (col2rgb can do it, but not in a convenient format) if you
want to add alpha to it.

Duncan Murdoch

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Re: Plot Rect Transparency

reichmaj
Duncan

Thanks I was able to find it in the help doc.

x <- c(1,2,4,6,8,9,10,12,13,14,18,20)
y <- c(4,5,3,6,7,4,8,9,12,4,7,5)

mydata <- data.frame(x,y)

plot(mydata)
rect(5,0,8,8, col=rgb(0,1,0,alpha=0.2), border=F)

-----Original Message-----
From: Duncan Murdoch <[hidden email]>
Sent: Thursday, June 28, 2018 7:57 PM
To: [hidden email]; [hidden email]
Subject: Re: [R] Plot Rect Transparency

On 28/06/2018 5:29 PM, Jeff Reichman wrote:

> R-Help
>
>  
>
> Is there a way to make a rectangle transparent (alpha=0.1??)
>
>  
>
>    plot(c(100, 200), c(300, 450), type= "n", xlab = "", ylab = "")
>
>     rect(110, 300, 175, 350, density = 5, border = "red")
>
>  
>
> Can't figure out how to take the changepoint function results and plot
> in
> ggplot2 so I can just simply add rectangles to the plot function, but
> I need to make transparent and there doesn't seem to be an alpha option.

Alpha is part of the colour spec.  For example,

rect(110, 300, 175, 350, density = 5, border = rgb("red")


rect(110, 300, 175, 350, density = 5, border = rgb(red=1, green=0, blue=0, alpha=0.1))

I'm not sure what is the quickest way to work out the rgb values for a named colour (col2rgb can do it, but not in a convenient format) if you want to add alpha to it.

Duncan Murdoch

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.