[R] modify rectangle color from image
Hi, I need some suggestion on how I could modify the color on some rectangle that I have created using image. In other words, I have a 5x5 matrix, say, m. m - matrix(rnorm(25), nrow=5) I create a grid of rectangles by: image(m) Now I want to change the color of rectangle (3,3) to blue. I don't know how this could be done, and searching the web has given me no hint. Thanks for your help. -- saurav __ R-help@stat.math.ethz.ch mailing list 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.
Re: [R] modify rectangle color from image
Thanks, Saurav Saurav Pathak [Wed, Jan 24, 2007 at 04:37:20PM -0500]: + Hi, + + I need some suggestion on how I could modify the color on some + rectangle that I have created using image. + + In other words, I have a 5x5 matrix, say, m. + + m - matrix(rnorm(25), nrow=5) + + I create a grid of rectangles by: + + image(m) + + Now I want to change the color of rectangle (3,3) to blue. using rect for this. DUH. -- saurav __ R-help@stat.math.ethz.ch mailing list 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.
Re: [R] modify rectangle color from image
On Wed, 2007-01-24 at 16:37 -0500, Saurav Pathak wrote: Hi, I need some suggestion on how I could modify the color on some rectangle that I have created using image. In other words, I have a 5x5 matrix, say, m. m - matrix(rnorm(25), nrow=5) I create a grid of rectangles by: image(m) Now I want to change the color of rectangle (3,3) to blue. I don't know how this could be done, and searching the web has given me no hint. Thanks for your help. Try this: m - matrix(rnorm(25), nrow = 5) image(m) # Get the plot region coords USR - par(usr) # Calc the length of a side of a square SIDE - abs(USR[1] - USR[2]) / 5 # Draw the rect using the appropriate offsets rect(USR[1] + (SIDE * 2), USR[3] + (SIDE * 2), USR[1] + (SIDE * 3), USR[3] + (SIDE * 3), col = blue) See ?par and review usr, then see ?rect par(usr) gives you the coordinates of the plot region. Then just do the math to calculate the coordinates of each rectangle. HTH, Marc Schwartz __ R-help@stat.math.ethz.ch mailing list 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.
