2 files changed, 83 insertions, 2 deletions
diff --git a/R/corplot.R b/R/corplot.R
new file mode 100644
index 0000000..c18e904
--- /dev/null
+++ b/R/corplot.R
@@ -0,0 +1,79 @@
+utils::globalVariables(c('i', 'j', 'value'))
+#' Correlation PLot (Upper Triangle)
+#'
+#' Minimal ggplot2 correlation plot showing the upper triangle
+#' in the top-right corner with no axis labels.
+#' @param R A square numeric correlation matrix
+#' @param title Optional plot title
+#'
+#' @return A ggplot object
+#'
+#' @examples
+#' X <- matrix(data = rnorm(100), nrow = 10)
+#' R <- cor(X)
+#' corplot(R, title = 'Example Correlation Plot')
+#'
+#' @importFrom reshape2 melt
+#' @import ggplot2
+#' @export
+corplot <- function(R, title = NULL){
+	R <- tryCatch({
+		if(is.matrix(R)){
+			if(nrow(R) == ncol(R)){
+				R[upper.tri(R)]
+			}
+		}else if(is.vector(R)){
+			m <- length(R)
+			n <- (1 + sqrt(1 + 8 * m)) / 2
+			if(n == floor(n)){
+				R
+			}else{
+				stop('Input length not compatible with upper triangle')
+			}
+		}else{
+			Rm <- as.matrix(R)
+			if(nrow(Rm) == ncol(Rm)){
+				Rm[upper.tri(Rm)]
+			}
+		}
+	}, error = function(e){
+		stop(paste('Invalid input for corplot:', e$message))
+	})
+
+	# Now get a df from the upper triangle
+	m <- length(R)
+	n <- as.integer((1 + sqrt(1 + 8 * m)) / 2)
+	M <- matrix(NA, n, n)
+	M[upper.tri(M)] <- R
+	df <- reshape2::melt(M, na.rm = TRUE)
+	colnames(df) <- c('i', 'j', 'value')
+	df$i <- factor(df$i, levels = 1:n)
+	df$j <- factor(df$j, levels = 1:n)
+
+	# And plot it
+	p <- ggplot2::ggplot(
+		data = df,
+		ggplot2::aes(x = i, y = j, fill = value)
+	) +
+	ggplot2::geom_tile() +
+	ggplot2::scale_fill_gradient2(
+		low = 'red',
+		mid = 'white',
+		high = 'blue',
+		midpoint = 0,
+		name = expression(rho)
+	) +
+	ggplot2::scale_x_discrete(limits = rev(levels(df$i))) +
+	ggplot2::scale_y_discrete(limits = levels(df$j)) +
+	ggplot2::coord_fixed() +
+	ggplot2::theme_void()
+
+	if(!is.null(title)){
+		p <- p +
+		ggplot2::ggtitle(title) +
+		ggplot2::theme(
+			plot.title = ggplot2::element_text(hjust = 0.5)
+		)
+	}
+	return(p)
+}
diff --git a/R/gg_csobczak.R b/R/gg_csobczak.R
index 97448a3..2817637 100644
--- a/R/gg_csobczak.R
+++ b/R/gg_csobczak.R
@@ -4,10 +4,12 @@
 #' @param p A ggplot object to add formatting to.
 #' @keywords ggplot plot p
 #' @export
+#' @import ggplot2
 #' @examples
 #' df <- data.frame(x=rnorm(10), y=rnorm(10))
-#' p <- ggplot(data=df, aes(x=x, y=y)) + geom_point()
+#' p <- ggplot2::ggplot(data=df, ggplot2::aes(x = x, y = y)) + ggplot2::geom_point()
 #' p <- gg_csobczak(p)
 gg_csobczak <- function(p){
-	p + theme_classic()
+	p <- p + ggplot2::theme_classic()
+	return(p)
 }