## Arne Schillert 07.07.2008
## new written Venn diagram
## inspired by library limma's venn.diagram

qcVenn <- function(A, B, C, labels, textSize = 1,
                   labelSize = 1.2, numberSnps)
{
  p1 <- length(setdiff(A, union(B, C)))
  p2 <- length(setdiff(intersect(A, B), C))
  p3 <- length(setdiff(B, union(A, C)))
  p4 <- length(setdiff(intersect(A, C), B))
  p5 <- length(intersect(intersect(A, B), C))
  p6 <- length(setdiff(intersect(B, C), A))
  p7 <- length(setdiff(C, union(A, B)))
  counts <- c(p1, p2, p3, p4, p5, p6, p7)

  ## circles:
  xCen <- c(-1, 1, 0)
  yCen <- c(1/sqrt(3), 1/sqrt(3), -2/sqrt(3))
  r <- 1.5
  theta <- 2 * pi * (1:720)/720
  par(mai = c(0, 0, 0, 0))
  plot(0, type = "n", xlim = c(-3.2, 3.2),
       ylim = c(-3.2,3.2), axes = FALSE,
       xlab = "", ylab = "")
  for(i in seq(along = xCen))
      {
        lines(xCen[i] + r * cos(theta),
              yCen[i] + r * sin(theta), lwd = 1.2)
      }
  xD <- 2
  yD <- sqrt(3)
  xBig <- 0.8
  xSmall <- 0.4
  yBig <- 0.7
  ySmall <- 0.4
  xPos <- c(xCen[1] - xSmall, 0, xCen[2] + xSmall,
            -xBig, 0, xBig, 0)
  yPos <- c(yCen[1] + ySmall, yCen[1] + ySmall, yCen[1] + ySmall,
            yCen[3] + yBig, yCen[2] - sqrt(5)/4,yCen[3] + yBig,
            yCen[3] -ySmall)
  text(xPos, yPos, counts, cex = textSize)
  text(c(-1.1, 1.1, 0), c(2.45, 2.45, -3.1),
       labels, cex = labelSize)
  nOut <- length(unique(c(A, B, C)))
  text(-1.7, 3.1 , paste("total:" ,numberSnps),
       cex = 1.2)
  text(2.1, 3.1 , paste("total excluded:" ,nOut),
       cex = 1.2)
  
  
  ## adding number of SNPs which passed each criterion

  ns <- c(length(A), length(B), length(C))


  for(i in 1:3){
    text(1.5, (-2.1 - 0.25 * i),
         sprintf("%s: ", labels[i]),
         cex = 1.2, adj = 0, font = 7)
    text(2.95, (-2.1 - 0.25 * i), ns[i],
         cex = 1.2, adj = 1)
  }
  
}