Emit axes for unbound colorbars

src/tikzplotlib/_axes.py

@@ -17,24 +17,26 @@ def __init__(self, data, obj):  # noqa: C901
         """Returns the PGFPlots code for an axis environment."""
         self.content = []
 
-        # Are we dealing with an axis that hosts a colorbar? Skip then, those are
-        # treated implicitily by the associated axis.
-        self.is_colorbar = _is_colorbar_heuristic(obj)
-        if self.is_colorbar:
-            return
-
         # instantiation
         self.nsubplots = 1
         self.subplot_index = 0
         self.is_subplot = False
 
-        if isinstance(obj, mpl.axes.Subplot):
+        self.axis_options = []
+
+        # Are we dealing with an axis that hosts a colorbar? Skip then, those are
+        # treated implicitily by the associated axis.
+        self.is_colorbar = _is_colorbar_heuristic(obj)
+
+        if isinstance(obj, mpl.axes.Subplot) and not self.is_colorbar:
             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:
+        # unassociated colorbars should have hidden axes; colorbars associated to axes will be printed by the axis
+        if not (obj.axison and self.is_visible) or self.is_colorbar:
             self.axis_options.append("hide x axis")
             self.axis_options.append("hide y axis")
 
@@ -153,10 +155,9 @@ def __init__(self, data, obj):  # noqa: C901
         if col != "white":
             self.axis_options.append(f"axis background/.style={{fill={col}}}")
 
-        # find color bar
-        colorbar = _find_associated_colorbar(obj)
-        if colorbar:
-            self._colorbar(colorbar, data)
+        self.colorbar = _find_associated_colorbar(obj)
+        if self.colorbar:
+            self._colorbar(self.colorbar, data)
 
         if self.is_subplot:
             self.content.append("\n\\nextgroupplot")
@@ -800,7 +801,7 @@ def _handle_listed_color_map(cmap, data):
     if cmap.N is None or cmap.N == len(cmap.colors):
         colors = [
             f"rgb({k}{unit})=({rgb[0]:{ff}},{rgb[1]:{ff}},{rgb[2]:{ff}})"
-            for k, rgb in enumerate(cmap.colors)
+            for k, rgb in enumerate(map(mpl.colors.to_rgb, cmap.colors))
         ]
     else:
         reps = int(float(cmap.N) / len(cmap.colors) - 0.5) + 1
@@ -858,6 +859,12 @@ def _find_associated_colorbar(obj):
     next axis environment, and see if it is de facto a color bar; if yes, return the
     color bar object.
     """
+    try:
+        cbar = obj._colorbar
+        if cbar is not None:
+            return cbar
+    except AttributeError:
+        pass
     for child in obj.get_children():
         try:
             cbar = child.colorbar

src/tikzplotlib/_save.py

@@ -328,6 +328,9 @@ def _recurse(data, obj):
     """Iterates over all children of the current object, gathers the contents
     contributing to the resulting PGFPlots file, and returns those.
     """
+    # bound_colorbars holds colorbars that are associated to axes
+    # we don't add axes from colorbars if they come after the axis to which they were associated
+    bound_colorbars = []
     content = _ContentManager()
     for child in obj.get_children():
         # Some patches are Spines, too; skip those entirely.
@@ -338,18 +341,25 @@ def _recurse(data, obj):
         if isinstance(child, mpl.axes.Axes):
             ax = _axes.Axes(data, child)
 
-            if ax.is_colorbar:
+            if ax.is_colorbar and any(ax.colorbar is cb for cb in bound_colorbars):
                 continue
 
+            if not ax.is_colorbar and ax.colorbar is not None:
+                bound_colorbars.append(ax.colorbar)
+
             # add extra axis options
             if data["extra axis options [base]"]:
                 ax.axis_options.extend(data["extra axis options [base]"])
 
             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 and not ax.is_colorbar:
+                # 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 +1,92 @@
 \begin{tikzpicture}
 
+\definecolor{darkgray176}{RGB}{176,176,176}
+
+\begin{axis}[
+colorbar horizontal,
+colormap={mymap}{[1pt]
+  rgb(0pt)=(0,1,1);
+  rgb(1pt)=(1,0,1)
+},
+hide x axis,
+hide y axis,
+point meta max=10,
+point meta min=-5,
+tick align=outside,
+tick pos=left,
+x grid style={darkgray176},
+xlabel={Some Units},
+xmin=-5, xmax=10,
+xtick style={color=black},
+ymin=0, ymax=1
+]
+\end{axis}
+
+\begin{axis}[
+colorbar horizontal,
+colormap={mymap}{[1pt]
+ rgb(0pt)=(1,0,0);
+  rgb(1pt)=(0,0.5,0);
+  rgb(2pt)=(0,0,1);
+  rgb(3pt)=(0,0.75,0.75)
+},
+hide x axis,
+hide y axis,
+point meta max=8,
+point meta min=1,
+tick align=outside,
+tick pos=left,
+x grid style={darkgray176},
+xlabel={Discrete intervals, some other units},
+xmin=1, xmax=8,
+xtick style={color=black},
+ymin=0, ymax=1
+]
+\end{axis}
+
+\begin{axis}[
+colorbar horizontal,
+colormap={mymap}{[1pt]
+ rgb(0pt)=(0,0.4,1);
+  rgb(1pt)=(0,0.8,1);
+  rgb(2pt)=(1,0.8,0);
+  rgb(3pt)=(1,0.4,0)
+},
+hide x axis,
+hide y axis,
+point meta max=1,
+point meta min=-1,
+tick align=outside,
+tick pos=left,
+x grid style={darkgray176},
+xlabel={Custom extension lengths, some other units},
+xmin=-1, xmax=1,
+xtick style={color=black},
+ymin=0, ymax=1
+]
+\end{axis}
+
+\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}