Plot the confusion matrix for a 10-class MNIST handwritten digit classification problem

rwml-R_figure4_19.R

library(caret)
library(kknn)
library(RColorBrewer)
library(cowplot)

mnist <- read.csv("data/mnist_small.csv",
                  colClasses = c(label = "factor"))

trainIndex <- createDataPartition(mnist$label, p = .8, 
                                  list = FALSE, 
                                  times = 1)
mnistTrain <- mnist[ trainIndex,]
mnistTest  <- mnist[-trainIndex,]

mnist.kknn <- kknn(label~., mnistTrain, mnistTest, distance = 1,
                   kernel = "triangular")

confusionDF <- data.frame(confusionMatrix(fitted(mnist.kknn),mnistTest$label)$table)
confusionDF$Reference = with(confusionDF, 
                             factor(Reference, levels = rev(levels(Reference))))

jBuPuFun <- colorRampPalette(brewer.pal(n = 9, "BuPu"))
paletteSize <- 256
jBuPuPalette <- jBuPuFun(paletteSize)

confusionPlot <- ggplot(
  confusionDF, aes(x = Prediction, y = Reference, fill = Freq)) +
  theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust = 0.5)) +
  geom_tile() +
  labs(x = "Predicted digit", y = "Actual digit") +
  scale_fill_gradient2(
    low = jBuPuPalette[1],
    mid = jBuPuPalette[paletteSize/2],
    high = jBuPuPalette[paletteSize],
    midpoint = (max(confusionDF$Freq) + min(confusionDF$Freq)) / 2,
    name = "") +
  theme(legend.key.height = unit(2, "cm"))

ggdraw(switch_axis_position(confusionPlot, axis = 'x'))

And secondly, how can i print the value rather that putting the colors in confusion matrx?

Thanks