library(cairoDevice)

drawMatrix <- function(x) {
  image(matrix(x,16,16)[,16:1],col=rev(gray((0:100)/100)),xaxt="n",yaxt="n",xlab="",ylab="",bty="n")
}

drawImage <- function() {
  img <- matrix(0,16,16)
  if (!is.null(coords)) {
    coordsI <- ceiling(coords)
    coordsI[coordsI > 16] <- 16
    coordsI[coordsI < 1] <- 1
    coordsI[,2] <- 17-coordsI[,2]
    counts <- table(coordsI[,1],coordsI[,2])
    img <- matrix(0,16,16)
    img[as.numeric(rownames(counts)), as.numeric(colnames(counts))] <- counts
    mx <- max(img)
    mn <- min(img)
    img <- (img-mn) / (mx-mn) * 2 - 1
  }
  drawMatrix(img)
  img
}

plotEmpty <- function(a=0,b=1) {
  plot(c(a,b),c(a,b),type="n",bty="n",xaxt="n",yaxt="n",xlab="",ylab="")
}

processAndClassify <- function() {
  dev.set(which=dev.next())
  x <- t(matrix(drawImage()))
  probs <- useNNLogReg(nnet,matrix(x,nrow=1),probs=TRUE)
  ### make bar plot with probs
  ### draw digit that is class label of x
  dev.set(which=dev.next())
}

######################################################################


####  Read zip code data.
####  Train neural net to make nnet



x11(type="Xlib",width=3,height=3)


Cairo(width=2,height=2)  ## for drawing
par(mar=c(0,0,0,0))

coords <- NULL
drawingG <- FALSE
plotEmpty(0,16)

getGraphicsEvent("Hold left down to draw. Click right to restart. Middle to stop.",
    onMouseDown = function(buttons,x,y) {
      if (buttons == 0) {
        drawingG <<- TRUE
        NULL
      } else if (buttons == 2) {
        coords <<- NULL
        plotEmpty(0,16)
        NULL
      } else if (buttons == 1) {
        return(TRUE)
      }
    },
    onMouseUp = function(buttons,x,y) {
      drawingG <<- FALSE
      processAndClassify()
      NULL
    },
    onMouseMove = function(buttons,x,y) {
      if (drawingG) {
        px <- grconvertX(x, "ndc", "user")
        py <- grconvertY(y, "ndc", "user")    
        coords <<- rbind(coords,c(px,py))
        points(px,py,pch=19,cex=3)
        if (nrow(coords) %% 100 == 0) {
          processAndClassify()
        }
      }
      NULL
    })