Continuous / gradient legend

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: tinyplot
 Type: Package
 Title: Lightweight Extension of the Base R Graphics System
-Version: 0.0.5.9000
+Version: 0.0.5.9001
 Authors@R: 
   c(
     person(

NAMESPACE

@@ -8,12 +8,15 @@ export(plt)
 export(tinyplot)
 export(tpar)
 importFrom(grDevices,adjustcolor)
+importFrom(grDevices,as.raster)
+importFrom(grDevices,colorRampPalette)
 importFrom(grDevices,extendrange)
 importFrom(grDevices,hcl.colors)
 importFrom(grDevices,hcl.pals)
 importFrom(grDevices,palette)
 importFrom(grDevices,palette.colors)
 importFrom(grDevices,palette.pals)
+importFrom(grDevices,recordGraphics)
 importFrom(grDevices,xy.coords)
 importFrom(graphics,Axis)
 importFrom(graphics,abline)
@@ -30,6 +33,7 @@ importFrom(graphics,plot.new)
 importFrom(graphics,plot.window)
 importFrom(graphics,points)
 importFrom(graphics,polygon)
+importFrom(graphics,rasterImage)
 importFrom(graphics,rect)
 importFrom(graphics,segments)
 importFrom(graphics,text)
@@ -38,6 +42,7 @@ importFrom(methods,as)
 importFrom(stats,as.formula)
 importFrom(stats,model.frame)
 importFrom(stats,na.omit)
+importFrom(stats,terms)
 importFrom(stats,update)
 importFrom(utils,head)
 importFrom(utils,modifyList)

NEWS.md

@@ -1,7 +1,14 @@
 # News
 
-## 0.0.5.9000 (development version)
-
+## 0.0.5.9001 (development version)
+
+- Gradient legends are now supported if by a continuous variable is passed to
+`by`. The exact behaviour depends on how many unique groups are detected within
+the "by" variable. Specifically, a gradient legend will only be printed if more
+than 5 unique groups are detected. But this behaviour can fine-tuned by the user
+via the `tpar("legend.ugc")` parameter. Thanks to StackOverflow user mnel, whose
+answer [here](https://stackoverflow.com/a/13355440) provided the inspiration for
+the final implementation. (#122 @grantmcdermott)
 - Support user-supplied polygons. (#127 @grantmcdermott)
 
 ## 0.0.5

R/by_aesthetics.R

@@ -1,4 +1,9 @@
-by_col = function(ngrps = 1L, col = NULL, palette = NULL) {
+by_col = function(ngrps = 1L, col = NULL, palette = NULL, gradient = NULL) {
+
+  if (is.null(gradient)) gradient = FALSE
+  if (isTRUE(gradient)) {
+    ngrps = 100L
+  }
 
   # palette = substitute(palette, env = parent.env(environment()))
 
@@ -45,6 +50,10 @@ by_col = function(ngrps = 1L, col = NULL, palette = NULL) {
       if (!is.na(pal_match)) {
         if (pal_match < 1L) stop("'palette' is ambiguous")
         palette_fun = palette.colors
+        if (isTRUE(gradient)) {
+          palette_fun2 = function(n, palette) colorRampPalette(palette.colors(palette = palette))(n)
+          palette_fun = palette_fun2
+        }
       } else {
         pal_match = charmatch(fx(palette), fx(hcl.pals()))
         if (!is.na(pal_match)) {