With the suggestion of Jim Holtman I have successfully implemented the loop
containing locator() using RGUI by toggling the buffer to OFF. However, I am
using JavaGD and the loop still will not work so the Java graphics window is
apparently buffered and I can't figure out how to turn it off. I really like
Java JGR and its JavaGD. I haven't been able to get the info from
www.rosuda.org so if anyone has solved this buffer problem with JavaGD I would
appreciate a note.
----- Original Message -----
From: jim holtman
To: Bob Meglen
Cc: r-help@r-project.org
Sent: Sunday, May 24, 2009 5:06 PM
Subject: Re: [R] Timing issue using locator() in loop containing print()
Is the output buffered on the RGUI? If so, uncheck it and see if the problem
clears up.
On Sun, May 24, 2009 at 3:24 PM, Bob Meglen <bmeg...@comcast.net> wrote:
I am attempting to use locator(n=2) to select the corners of several (5 in
this case) rectangles on an image displayed in a JavaGD window. The returned
coords are used to draw labeled rectangles around the selected region. I have
tried several things to get this to work including sys.Sleep to correct what
appears to be a timing issue with this loop. The first-time print in the loop
doesn't print before locator executes several mouse clicks, and the order of
pt(1) and pt(2) in each execution of the loop gets out of sync. Please offer a
suggestion.
I am using Windows, Java Gui for R1.6-3, R version 2.8.1.
Example:
#..........................................................PLOT the Image
in Java
Window.........................................................................
JavaGD(name="JavaGD", width=640, height=480)
#.........................................suppress margins all
around.........................
par(mar=c(0,0,0,0))
image(xraw,col=my.grays(256),axes=F)
#....................................Set up
loop..........................................................................................................
tot_subsets<-5
ss<- matrix(0,nrow=tot_subsets,ncol=4)
print("begin selections")
# .........................Loop for multiple rectangle selections on
image.....................................................
for (i in 1:tot_subsets) {
print("Select lower left and upper right for this rectangle")
sub_0<- locator(n=2)
rect(sub_0$x[1],sub_0$y[1],sub_0$x[2],sub_0$y[2],col="red",density=0)
text(sub_0$x[1]+(sub_0$x[2]-sub_0$x[1])/2,sub_0$y[1]+(sub_0$y[2]-sub_0$y[1])/2,paste("S",i),col="red")
#.......................Add each reactangle coords to master subset
list.................................................
ss[i,1]<-sub_0$x[1]
ss[i,2]<-sub_0$y[1]
ss[i,3]<-sub_0$x[2]
ss[i,4]<-sub_0$y[2]
}
print("finished selection")
Thanks,
Bob Meglen
Boulder, CO
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--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
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