PyPlot: fix label position and annotate color bar

src/pyplot.jl

@@ -225,24 +225,39 @@ function gridplot!(ctx, TP::Type{PyPlotType}, ::Type{Val{2}}, grid)
     brflag = ones(Bool, nbfaceregions)
     ax.set_aspect(ctx[:aspect])
     tridat = tridata(grid, ctx[:gridscale])
-    cmap = region_cmap(ncellregions)
+    # PyPlot.ColorMap cannot handle n ≤ 1, TODO: use other color mappings!
+    cmap  = region_cmap( max( 2, ncellregions ) )
+    bcmap = bregion_cmap( max( 2, nbfaceregions ) )
+
+    bcdata = ax.tripcolor(tridat...;
+        facecolors = cellcolors(grid, ctx[:cellcoloring]),
+        cmap = PyPlot.ColorMap(bcmap, length(bcmap)),
+        vmin = 0.5,
+        vmax = length(bcmap)+0.5,)
+
+    # this simply overwrites the plotting done in "bcdata = " ...
     cdata = ax.tripcolor(tridat...;
-                         facecolors = cellcolors(grid, ctx[:cellcoloring]),
-                         cmap = PyPlot.ColorMap(cmap, length(cmap)),
-                         vmin = 1.0,
-                         vmax = length(cmap),)
+        facecolors = cellcolors(grid, ctx[:cellcoloring]),
+        cmap = PyPlot.ColorMap(cmap, length(cmap)),
+        vmin = 0.5,
+        vmax = length(cmap)+0.5,)
+
     if ctx[:colorbar] == :horizontal
-        cbar = fig.colorbar(cdata;
+        cbar = fig.colorbar(bcdata;
                             ax = ax,
-                            ticks = collect(1:length(cmap)),
-                            orientation = "horizontal",)
+                            ticks = collect(1:length(bcmap)),
+                            orientation = "horizontal",
+                            label = "boundary regions",
+                           )
     end
 
     if ctx[:colorbar] == :vertical
-        cbar = fig.colorbar(cdata;
+        cbar = fig.colorbar(bcdata;
                             ax = ax,
-                            ticks = collect(1:length(cmap)),
-                            orientation = "vertical",)
+                            ticks = collect(1:length(bcmap)),
+                            orientation = "vertical",
+                            label = "boundary regions",
+                           )
     end
 
     ax.triplot(tridat...; color = "k", linewidth = ctx[:linewidth])