Hide invisible axes while still displaying colorbars

src/tikzplotlib/_axes.py

@@ -32,9 +32,10 @@ def __init__(self, data, obj):  # noqa: C901
             self._subplot(obj, data)
 
         self.axis_options = []
+        self.is_visible = obj.get_visible()
 
         # check if axes need to be displayed at all
-        if not obj.axison:
+        if not (obj.axison and self.is_visible):
             self.axis_options.append("hide x axis")
             self.axis_options.append("hide y axis")
 

src/tikzplotlib/_save.py

@@ -348,8 +348,12 @@ def _recurse(data, obj):
             data["current mpl axes obj"] = child
             data["current axes"] = ax
 
-            # Run through the child objects, gather the content.
-            data, children_content = _recurse(data, child)
+            if ax.is_visible:
+                # Run through the child objects, gather the content.
+                data, children_content = _recurse(data, child)
+            else:
+                # we may still display the colorbar
+                children_content = []
 
             # populate content and add axis environment if desired
             if data["add axis environment"]:

tests/test_colorbars.py

@@ -4,7 +4,7 @@
 
 def plot():
     # Make a figure and axes with dimensions as desired.
-    fig, ax = plt.subplots(3)
+    fig, ax = plt.subplots(4)
 
     # Set the colormap and norm to correspond to the data for which the colorbar will be
     # used.
@@ -69,6 +69,16 @@ def plot():
     )
     cb3.set_label("Custom extension lengths, some other units")
 
+    # Set the colormap and norm to correspond to the data for which the colorbar will be
+    # used.  This time attach the colorbar to axes.
+    cmap = mpl.cm.cool
+    norm = mpl.colors.Normalize(vmin=-5, vmax=10)
+
+    img = ax[3].imshow([[0, 1]], cmap=cmap)
+    ax[3].set_visible(False)
+    cax = fig.add_axes([0.1, 1, 0.8, 0.1])
+    cb4 = fig.colorbar(img, cax=cax, orientation="horizontal", label="Some Units")
+
     return fig
 
 

tests/test_colorbars_reference.tex

@@ -1,3 +1,28 @@
 \begin{tikzpicture}
 
+\definecolor{darkgray176}{RGB}{176,176,176}
+
+\begin{groupplot}[group style={group size=1 by 4}]
+\nextgroupplot[
+colorbar horizontal,
+colormap={mymap}{[1pt]
+  rgb(0pt)=(0,1,1);
+  rgb(1pt)=(1,0,1)
+},
+hide x axis,
+hide y axis,
+point meta max=1,
+point meta min=0,
+tick align=outside,
+tick pos=left,
+x grid style={darkgray176},
+xmin=-0.5, xmax=1.5,
+xtick style={color=black},
+y dir=reverse,
+y grid style={darkgray176},
+ymin=-0.5, ymax=0.5,
+ytick style={color=black}
+]
+\end{groupplot}
+
 \end{tikzpicture}