From 2653e5cf7ddaadea45a0c437da4c91dff902c07c Mon Sep 17 00:00:00 2001
From: Mike Roberts <42875462+mrob95@users.noreply.github.com>
Date: Mon, 27 Jan 2020 16:36:03 +0000
Subject: [PATCH 1/4] Add NHSD colour utilities

---
 R/graph_colours.R | 141 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 R/graph_colours.R

diff --git a/R/graph_colours.R b/R/graph_colours.R
new file mode 100644
index 0000000..32bdfbe
--- /dev/null
+++ b/R/graph_colours.R
@@ -0,0 +1,141 @@
+#' NHS Digital core colours
+#'
+#' A large selection of NHS digital core colours, selected from
+#' https://digital.nhs.uk/about-nhs-digital/corporate-information-and-documents/nhs-digital-style-guidelines/how-we-look/colour-palette
+#'
+#' @export
+nhsd_core_colours = c(
+  "chart_grey_3" = "#F8F8F8",
+  "white" = "#FFFFFF",
+  "white_tints" = c("#F9FAFB", "#F3F5F6", "#EDEFF1", "#DEF2E5"),
+  "nhs_blue" = "#005EB8",
+  "blue_tints" = c("#337EC6", "#ACCAE8", "#D4E4F3", "#E6EFF8"),
+  "nhs_dark_grey" = "#425563",
+  "grey_tints" = c(
+    "#687784",
+    "#98A4AD",
+    "#B3BBC1",
+    "#DFE2E5",
+    "#EDEFF1",
+    "#F3F5F6",
+    "#F9FAFB"
+  ),
+  "nhs_mild_grey" = "#768692",
+  "nhs_warm_yellow" = "#FFB81C",
+  "warm_yellow_tints" = c("#FFE8B4", "#FFF1CC", "#FFF8E8")
+)
+
+
+#' NHS Digital chart colours
+#'
+#' A list of chart colours constructed from the NHS color palette.
+#' Contains the values "light blue", "blue", "dark blue", "warm yellow", "light grey", "grey" and "dark grey".
+#'
+#' @export
+nhsd_chart_colours = c(
+  `light blue` = "#71CCEF",
+  `blue` = "#005EB8",
+  `dark blue` = "#003087",
+  `warm yellow` = "#FFB81C",
+  `light grey` = "#D0D5D6",
+  `grey` = "#84919C",
+  `dark grey` = "#425563"
+)
+
+
+nhsd_cols <- function(...) {
+  cols <- c(...)
+  if (is.null(cols)) {
+    return (nhsd_colors)
+  }
+  nhsd_chart_colours[cols]
+}
+
+nhsd_palettes <- list(
+  `main` = nhsd_cols("warm yellow", "blue", "light blue", "dark blue"),
+
+  `blue` = nhsd_cols("light blue", "blue", "dark blue"),
+
+  `grey` = nhsd_cols("light grey", "grey", "dark grey")
+)
+
+nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
+  pal <- nhsd_palettes[[palette]]
+  if (reverse) {
+    pal <- rev(pal)
+  }
+  grDevices::colorRampPalette(pal, ...)
+}
+
+#' NHSD colour scale
+#'
+#' A ggplot compatible colour palette for producing NHS digital graphs.
+#'
+#' @param pallette Which color palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param discrete Whether this scale is discrete or continuous (default: TRUE)
+#' @param reverse Whether to reverse the scale (default: FALSE)
+#' @return A colour pallette, to be added to a ggplot plot object
+#'
+#' @examples
+#' library(gapminder)
+#'
+#' countries <- c("United Kingdom", "China", "Gambia")
+#'
+#' gapminder %>%
+#'   filter(country %in% countries) %>%
+#'   ggplot(aes(year, lifeExp, color=country)) +
+#'   geom_smooth(se = FALSE) +
+#'   labs(
+#'     title = "Life expectancy",
+#'     x = "Year",
+#'     y = "Expectancy",
+#'     caption = "Source: gapminder (2020)"
+#'     ) +
+#'   theme_minimal() +
+#'   scale_color_nhsd("blue") +
+#'   ggsave("test.png",
+#'          type = "cairo",
+#'          width = 7,
+#'          height = 4,
+#'   )
+#'
+#' @aliases scale_color_nhsd
+#' @export
+scale_colour_nhsd <- function(palette = "main", discrete = TRUE, reverse = FALSE, ...) {
+  pal <- nhsd_pal(palette = palette, reverse = reverse)
+
+  if (discrete) {
+    ggplot2::discrete_scale("colour", paste0("nhsd_", palette), palette = pal, ...)
+  } else {
+    ggplot2::scale_color_gradientn(colours = pal(256), ...)
+  }
+}
+
+#' @export
+scale_color_nhsd <- scale_colour_nhsd
+
+#' NHSD fill scale
+#'
+#' A ggplot compatible colour palette for producing NHS digital graphs.
+#'
+#' @param pallette Which color palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param discrete Whether this scale is discrete or continuous (default: FALSE)
+#' @param reverse Whether to reverse the scale (default: FALSE)
+#' @return A colour pallette
+#'
+#' @examples
+#' ggplot(faithfuld, aes(waiting, eruptions)) +
+#'     geom_raster(aes(fill = density)) +
+#'     theme_minimal() +
+#'     scale_fill_nhsd(discrete=FALSE, reverse=TRUE)
+#'
+#' @export
+scale_fill_nhsd <- function(palette = "main", discrete = TRUE, reverse = FALSE, ...) {
+  pal <- nhsd_pal(palette = palette, reverse = reverse)
+
+  if (discrete) {
+    ggplot2::discrete_scale("fill", paste0("nhsd_", palette), palette = pal, ...)
+  } else {
+    ggplot2::scale_fill_gradientn(colours = pal(256), ...)
+  }
+}
\ No newline at end of file

From d39aa3dc6f0431e2fa8d436b386aaf781af115ff Mon Sep 17 00:00:00 2001
From: Mike Roberts <42875462+mrob95@users.noreply.github.com>
Date: Mon, 27 Jan 2020 16:38:07 +0000
Subject: [PATCH 2/4] Rebuild documentation

---
 DESCRIPTION               |  2 +-
 NAMESPACE                 |  5 +++++
 R/graph_colours.R         | 12 +++++-----
 man/nhsd_chart_colours.Rd | 15 +++++++++++++
 man/nhsd_core_colours.Rd  | 15 +++++++++++++
 man/scale_colour_nhsd.Rd  | 46 +++++++++++++++++++++++++++++++++++++++
 man/scale_fill_nhsd.Rd    | 28 ++++++++++++++++++++++++
 7 files changed, 116 insertions(+), 7 deletions(-)
 create mode 100644 man/nhsd_chart_colours.Rd
 create mode 100644 man/nhsd_core_colours.Rd
 create mode 100644 man/scale_colour_nhsd.Rd
 create mode 100644 man/scale_fill_nhsd.Rd

diff --git a/DESCRIPTION b/DESCRIPTION
index 5ffbeed..a45a869 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -22,4 +22,4 @@ Imports:
 Suggests:
     testthat
 NeedsCompilation: no
-RoxygenNote: 6.1.1
+RoxygenNote: 7.0.2
diff --git a/NAMESPACE b/NAMESPACE
index c4ed42d..15e3bf5 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,3 +1,8 @@
 # Generated by roxygen2: do not edit by hand
 
 export(age_bands)
+export(nhsd_chart_colours)
+export(nhsd_core_colours)
+export(scale_color_nhsd)
+export(scale_colour_nhsd)
+export(scale_fill_nhsd)
diff --git a/R/graph_colours.R b/R/graph_colours.R
index 32bdfbe..e32a670 100644
--- a/R/graph_colours.R
+++ b/R/graph_colours.R
@@ -28,7 +28,7 @@ nhsd_core_colours = c(
 
 #' NHS Digital chart colours
 #'
-#' A list of chart colours constructed from the NHS color palette.
+#' A list of chart colours constructed from the NHS colour palette.
 #' Contains the values "light blue", "blue", "dark blue", "warm yellow", "light grey", "grey" and "dark grey".
 #'
 #' @export
@@ -46,7 +46,7 @@ nhsd_chart_colours = c(
 nhsd_cols <- function(...) {
   cols <- c(...)
   if (is.null(cols)) {
-    return (nhsd_colors)
+    return (nhsd_chart_colours)
   }
   nhsd_chart_colours[cols]
 }
@@ -71,7 +71,7 @@ nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
 #'
 #' A ggplot compatible colour palette for producing NHS digital graphs.
 #'
-#' @param pallette Which color palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param pallette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
 #' @param discrete Whether this scale is discrete or continuous (default: TRUE)
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette, to be added to a ggplot plot object
@@ -83,7 +83,7 @@ nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
 #'
 #' gapminder %>%
 #'   filter(country %in% countries) %>%
-#'   ggplot(aes(year, lifeExp, color=country)) +
+#'   ggplot(aes(year, lifeExp, colour=country)) +
 #'   geom_smooth(se = FALSE) +
 #'   labs(
 #'     title = "Life expectancy",
@@ -92,7 +92,7 @@ nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
 #'     caption = "Source: gapminder (2020)"
 #'     ) +
 #'   theme_minimal() +
-#'   scale_color_nhsd("blue") +
+#'   scale_colour_nhsd("blue") +
 #'   ggsave("test.png",
 #'          type = "cairo",
 #'          width = 7,
@@ -118,7 +118,7 @@ scale_color_nhsd <- scale_colour_nhsd
 #'
 #' A ggplot compatible colour palette for producing NHS digital graphs.
 #'
-#' @param pallette Which color palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param pallette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
 #' @param discrete Whether this scale is discrete or continuous (default: FALSE)
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette
diff --git a/man/nhsd_chart_colours.Rd b/man/nhsd_chart_colours.Rd
new file mode 100644
index 0000000..6e0d11f
--- /dev/null
+++ b/man/nhsd_chart_colours.Rd
@@ -0,0 +1,15 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/graph_colours.R
+\docType{data}
+\name{nhsd_chart_colours}
+\alias{nhsd_chart_colours}
+\title{NHS Digital chart colours}
+\format{An object of class \code{character} of length 7.}
+\usage{
+nhsd_chart_colours
+}
+\description{
+A list of chart colours constructed from the NHS colour palette.
+Contains the values "light blue", "blue", "dark blue", "warm yellow", "light grey", "grey" and "dark grey".
+}
+\keyword{datasets}
diff --git a/man/nhsd_core_colours.Rd b/man/nhsd_core_colours.Rd
new file mode 100644
index 0000000..157d4a8
--- /dev/null
+++ b/man/nhsd_core_colours.Rd
@@ -0,0 +1,15 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/graph_colours.R
+\docType{data}
+\name{nhsd_core_colours}
+\alias{nhsd_core_colours}
+\title{NHS Digital core colours}
+\format{An object of class \code{character} of length 24.}
+\usage{
+nhsd_core_colours
+}
+\description{
+A large selection of NHS digital core colours, selected from
+https://digital.nhs.uk/about-nhs-digital/corporate-information-and-documents/nhs-digital-style-guidelines/how-we-look/colour-palette
+}
+\keyword{datasets}
diff --git a/man/scale_colour_nhsd.Rd b/man/scale_colour_nhsd.Rd
new file mode 100644
index 0000000..814ad76
--- /dev/null
+++ b/man/scale_colour_nhsd.Rd
@@ -0,0 +1,46 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/graph_colours.R
+\name{scale_colour_nhsd}
+\alias{scale_colour_nhsd}
+\alias{scale_color_nhsd}
+\title{NHSD colour scale}
+\usage{
+scale_colour_nhsd(palette = "main", discrete = TRUE, reverse = FALSE, ...)
+}
+\arguments{
+\item{discrete}{Whether this scale is discrete or continuous (default: TRUE)}
+
+\item{reverse}{Whether to reverse the scale (default: FALSE)}
+
+\item{pallette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
+}
+\value{
+A colour pallette, to be added to a ggplot plot object
+}
+\description{
+A ggplot compatible colour palette for producing NHS digital graphs.
+}
+\examples{
+library(gapminder)
+
+countries <- c("United Kingdom", "China", "Gambia")
+
+gapminder \%>\%
+  filter(country \%in\% countries) \%>\%
+  ggplot(aes(year, lifeExp, colour=country)) +
+  geom_smooth(se = FALSE) +
+  labs(
+    title = "Life expectancy",
+    x = "Year",
+    y = "Expectancy",
+    caption = "Source: gapminder (2020)"
+    ) +
+  theme_minimal() +
+  scale_colour_nhsd("blue") +
+  ggsave("test.png",
+         type = "cairo",
+         width = 7,
+         height = 4,
+  )
+
+}
diff --git a/man/scale_fill_nhsd.Rd b/man/scale_fill_nhsd.Rd
new file mode 100644
index 0000000..73a7308
--- /dev/null
+++ b/man/scale_fill_nhsd.Rd
@@ -0,0 +1,28 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/graph_colours.R
+\name{scale_fill_nhsd}
+\alias{scale_fill_nhsd}
+\title{NHSD fill scale}
+\usage{
+scale_fill_nhsd(palette = "main", discrete = TRUE, reverse = FALSE, ...)
+}
+\arguments{
+\item{discrete}{Whether this scale is discrete or continuous (default: FALSE)}
+
+\item{reverse}{Whether to reverse the scale (default: FALSE)}
+
+\item{pallette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
+}
+\value{
+A colour pallette
+}
+\description{
+A ggplot compatible colour palette for producing NHS digital graphs.
+}
+\examples{
+ggplot(faithfuld, aes(waiting, eruptions)) +
+    geom_raster(aes(fill = density)) +
+    theme_minimal() +
+    scale_fill_nhsd(discrete=FALSE, reverse=TRUE)
+
+}

From d36814273ede6d640373650e149e74a4bec6f444 Mon Sep 17 00:00:00 2001
From: Mike Roberts <42875462+mrob95@users.noreply.github.com>
Date: Tue, 28 Jan 2020 09:54:59 +0000
Subject: [PATCH 3/4] Modify examples to make travis happy

---
 .travis.yml              |  3 ++-
 R/graph_colours.R        | 29 ++++++++---------------------
 man/scale_colour_nhsd.Rd | 27 ++++++---------------------
 man/scale_fill_nhsd.Rd   |  6 ++++--
 4 files changed, 20 insertions(+), 45 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index fda44de..938b341 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
-language: R  
+language: R
+r_packages: ggplot2
 cache: packages
 sudo: false
 warnings_are_errors: false
diff --git a/R/graph_colours.R b/R/graph_colours.R
index e32a670..2c78826 100644
--- a/R/graph_colours.R
+++ b/R/graph_colours.R
@@ -71,33 +71,18 @@ nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
 #'
 #' A ggplot compatible colour palette for producing NHS digital graphs.
 #'
-#' @param pallette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param palette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
 #' @param discrete Whether this scale is discrete or continuous (default: TRUE)
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette, to be added to a ggplot plot object
 #'
 #' @examples
-#' library(gapminder)
+#' library(ggplot2)
 #'
-#' countries <- c("United Kingdom", "China", "Gambia")
-#'
-#' gapminder %>%
-#'   filter(country %in% countries) %>%
-#'   ggplot(aes(year, lifeExp, colour=country)) +
-#'   geom_smooth(se = FALSE) +
-#'   labs(
-#'     title = "Life expectancy",
-#'     x = "Year",
-#'     y = "Expectancy",
-#'     caption = "Source: gapminder (2020)"
-#'     ) +
+#' ggplot(iris, aes(Sepal.Length, Petal.Length, colour=Species)) +
+#'   geom_point() +
 #'   theme_minimal() +
-#'   scale_colour_nhsd("blue") +
-#'   ggsave("test.png",
-#'          type = "cairo",
-#'          width = 7,
-#'          height = 4,
-#'   )
+#'   scale_colour_nhsd()
 #'
 #' @aliases scale_color_nhsd
 #' @export
@@ -118,12 +103,14 @@ scale_color_nhsd <- scale_colour_nhsd
 #'
 #' A ggplot compatible colour palette for producing NHS digital graphs.
 #'
-#' @param pallette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
+#' @param palette Which colour palette to use, can be "main", "blue", "grey" (default: "main")
 #' @param discrete Whether this scale is discrete or continuous (default: FALSE)
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette
 #'
 #' @examples
+#' library(ggplot2)
+#'
 #' ggplot(faithfuld, aes(waiting, eruptions)) +
 #'     geom_raster(aes(fill = density)) +
 #'     theme_minimal() +
diff --git a/man/scale_colour_nhsd.Rd b/man/scale_colour_nhsd.Rd
index 814ad76..f2ed06b 100644
--- a/man/scale_colour_nhsd.Rd
+++ b/man/scale_colour_nhsd.Rd
@@ -8,11 +8,11 @@
 scale_colour_nhsd(palette = "main", discrete = TRUE, reverse = FALSE, ...)
 }
 \arguments{
+\item{palette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
+
 \item{discrete}{Whether this scale is discrete or continuous (default: TRUE)}
 
 \item{reverse}{Whether to reverse the scale (default: FALSE)}
-
-\item{pallette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
 }
 \value{
 A colour pallette, to be added to a ggplot plot object
@@ -21,26 +21,11 @@ A colour pallette, to be added to a ggplot plot object
 A ggplot compatible colour palette for producing NHS digital graphs.
 }
 \examples{
-library(gapminder)
-
-countries <- c("United Kingdom", "China", "Gambia")
+library(ggplot2)
 
-gapminder \%>\%
-  filter(country \%in\% countries) \%>\%
-  ggplot(aes(year, lifeExp, colour=country)) +
-  geom_smooth(se = FALSE) +
-  labs(
-    title = "Life expectancy",
-    x = "Year",
-    y = "Expectancy",
-    caption = "Source: gapminder (2020)"
-    ) +
+ggplot(iris, aes(Sepal.Length, Petal.Length, colour=Species)) +
+  geom_point() +
   theme_minimal() +
-  scale_colour_nhsd("blue") +
-  ggsave("test.png",
-         type = "cairo",
-         width = 7,
-         height = 4,
-  )
+  scale_colour_nhsd()
 
 }
diff --git a/man/scale_fill_nhsd.Rd b/man/scale_fill_nhsd.Rd
index 73a7308..df60556 100644
--- a/man/scale_fill_nhsd.Rd
+++ b/man/scale_fill_nhsd.Rd
@@ -7,11 +7,11 @@
 scale_fill_nhsd(palette = "main", discrete = TRUE, reverse = FALSE, ...)
 }
 \arguments{
+\item{palette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
+
 \item{discrete}{Whether this scale is discrete or continuous (default: FALSE)}
 
 \item{reverse}{Whether to reverse the scale (default: FALSE)}
-
-\item{pallette}{Which colour palette to use, can be "main", "blue", "grey" (default: "main")}
 }
 \value{
 A colour pallette
@@ -20,6 +20,8 @@ A colour pallette
 A ggplot compatible colour palette for producing NHS digital graphs.
 }
 \examples{
+library(ggplot2)
+
 ggplot(faithfuld, aes(waiting, eruptions)) +
     geom_raster(aes(fill = density)) +
     theme_minimal() +

From 2e7330436c39b2caa319e6364abcf43205596f6f Mon Sep 17 00:00:00 2001
From: Mike Roberts <42875462+mrob95@users.noreply.github.com>
Date: Tue, 28 Jan 2020 10:59:07 +0000
Subject: [PATCH 4/4] Fix example imports

---
 DESCRIPTION              | 1 +
 NAMESPACE                | 1 +
 R/graph_colours.R        | 4 ++--
 man/scale_colour_nhsd.Rd | 1 -
 man/scale_fill_nhsd.Rd   | 1 -
 5 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index a45a869..8b098de 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,6 +18,7 @@ Description: Provides implementation of various methods of data analysis that wo
 License: BSD_3_clause + file LICENSE
 LazyData: false
 Imports:
+    ggplot2,
     MASS
 Suggests:
     testthat
diff --git a/NAMESPACE b/NAMESPACE
index 15e3bf5..ca02353 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -6,3 +6,4 @@ export(nhsd_core_colours)
 export(scale_color_nhsd)
 export(scale_colour_nhsd)
 export(scale_fill_nhsd)
+import(ggplot2)
diff --git a/R/graph_colours.R b/R/graph_colours.R
index 2c78826..3107d33 100644
--- a/R/graph_colours.R
+++ b/R/graph_colours.R
@@ -76,9 +76,9 @@ nhsd_pal <- function(palette = "main", reverse = FALSE, ...) {
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette, to be added to a ggplot plot object
 #'
+#' @import ggplot2
 #' @examples
 #' library(ggplot2)
-#'
 #' ggplot(iris, aes(Sepal.Length, Petal.Length, colour=Species)) +
 #'   geom_point() +
 #'   theme_minimal() +
@@ -108,9 +108,9 @@ scale_color_nhsd <- scale_colour_nhsd
 #' @param reverse Whether to reverse the scale (default: FALSE)
 #' @return A colour pallette
 #'
+#' @import ggplot2
 #' @examples
 #' library(ggplot2)
-#'
 #' ggplot(faithfuld, aes(waiting, eruptions)) +
 #'     geom_raster(aes(fill = density)) +
 #'     theme_minimal() +
diff --git a/man/scale_colour_nhsd.Rd b/man/scale_colour_nhsd.Rd
index f2ed06b..0ba0532 100644
--- a/man/scale_colour_nhsd.Rd
+++ b/man/scale_colour_nhsd.Rd
@@ -22,7 +22,6 @@ A ggplot compatible colour palette for producing NHS digital graphs.
 }
 \examples{
 library(ggplot2)
-
 ggplot(iris, aes(Sepal.Length, Petal.Length, colour=Species)) +
   geom_point() +
   theme_minimal() +
diff --git a/man/scale_fill_nhsd.Rd b/man/scale_fill_nhsd.Rd
index df60556..14f0e5a 100644
--- a/man/scale_fill_nhsd.Rd
+++ b/man/scale_fill_nhsd.Rd
@@ -21,7 +21,6 @@ A ggplot compatible colour palette for producing NHS digital graphs.
 }
 \examples{
 library(ggplot2)
-
 ggplot(faithfuld, aes(waiting, eruptions)) +
     geom_raster(aes(fill = density)) +
     theme_minimal() +