cylindrect: Display an apparent cylinder

Description

Display rectangles shaded to appear like cylinders.

Usage

cylindrect(xleft,ybottom,xright,ytop,col,border=NA,gradient="x",nslices=50)

Arguments

xleft

The position of the left side of the rectangle(s).

ybottom

The position of the bottom of the rectangle(s).

xright

The position of the right side of the rectangle(s).

ytop

The position of the top side of the rectangle(s).

col

The base color(s) of the rectangles.

border

Whether to draw a border and what color.

gradient

Whether to vary the shading horizontally ("x" - the default) or vertically (anything but "x").

nslices

The number of "slices" of color for shading.

Value

The base color(s) of the rectangle(s).

Details

cylindrect displays a rectangle filled with "slices" of color that simulate the appearance of a cylinder. The slices are calculated so that the base color appears at the right or bottom edge of the rectangle, become progressively lighter to a "highlight" at two thirds of the width or height and then darken toward the base color again. The appearance is of a cylinder lit from above and to the left of the viewer. The position of the apparent light source is hard coded into the function.

Examples

Run this code

plot(0,xlim=c(0,5),ylim=c(0,5),main="Examples of pseudocylindrical rectangles",
  xlab="",ylab="",axes=FALSE,type="n")
 cylindrect(0,0,1,5,"red")
 cylindrect(rep(1,3),c(0,2,4),rep(4,3),c(1,3,5),"green",gradient="y")
 cylindrect(4,0,5,5,"#8844aa")