resizeCircles: Match the areas of the 2 circles and their overlap to the input values for X, Y and the intersection of X and Y.

Description

Calculates the radii of the two circles relative to a fixed center-to-center distance. The areas of the circles and their overlap will be proportionate the three input values of X alone, Y alone and the intersection of X and Y. The method used is described in http://elliotnoma.wordpress.com/2013/03/17/spacing-circles-in-a-2-item-venn-diagram/.

Usage

resizeCircles(x_only, y_only, overlap, standardDistance = sqrt(0.5))

Arguments

x_only

a numeric value representing the relative size of X excluding its intersection with Y.

y_only

a numeric value representing the relaitive size of Y excluding its intersection with X.

overlap

a numeric value representing the relative size of the intersection of X and Y.

standardDistance

a numeric value specifying the fixed center-to-center distance to which the radii are matched. The default value is that used by plotVenn2d

Details

This function is designed to be used in conjunction with the plotVenn2d function. plotVenn2d plots the circles with a fixed center-to-center distance as set by the standardDistance argument. This routine specifies the radii of the circles to control their overlap relative to the fixed center-to-center distance. To increase or decrease the center-to-center distance in plotVenn2d, use the resizePlot parameter.

The function assumes that the first two arguments are for X-excluding the intersection and Y-excluding the intersection. The total X amount equals this first and third arguments. The total Y amount equals the second and third arguments.

Examples

Run this code

  plot.new()
  plotVenn2d(rep("",3), radius=resizeCircles(20,.5, 3), Title=NULL, 
    resizePlot=0.7, labels=c("",""))

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