ENH: Add API to manage view state in custom Axes.

QuLogic · QuLogic · commit c6151a32baa3 · 2015-07-26T03:47:55.000-04:00
Custom Axes may require additional information than simply the x/y
limits to describe the view. This API will allow the navigation buttons
on the toolbar to function correctly with such Axes.
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -3132,6 +3132,35 @@ def set_navigate_mode(self, b):
         """
         self._navigate_mode = b
 
+    def save_view(self):
+        """
+        Save information required to reproduce the current view.
+
+        Called before a view is changed, such as during a pan or zoom
+        initiated by the user.
+
+        .. note::
+
+            Intended to be overridden by new projection types, but if not, the
+            default implementation saves the view limits. You *must* implement
+            :meth:`restore_view` if you implement this method.
+        """
+        raise NotImplementedError
+
+    def restore_view(self, view):
+        """
+        Apply a previously saved view.
+
+        Called when restoring a view, such as with the navigation buttons.
+
+        .. note::
+
+            Intended to be overridden by new projection types, but if not, the
+            default implementation restores the view limits. You *must*
+            implement :meth:`save_view` if you implement this method.
+        """
+        raise NotImplementedError
+
     def start_pan(self, x, y, button):
         """
         Called when a pan operation has started.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -2953,9 +2953,14 @@ def push_current(self):
         lims = []
         pos = []
         for a in self.canvas.figure.get_axes():
-            xmin, xmax = a.get_xlim()
-            ymin, ymax = a.get_ylim()
-            lims.append((xmin, xmax, ymin, ymax))
+            try:
+                view = a.save_view()
+            except NotImplementedError:
+                xmin, xmax = a.get_xlim()
+                ymin, ymax = a.get_ylim()
+                lims.append((xmin, xmax, ymin, ymax))
+            else:
+                lims.append(view)
             # Store both the original and modified positions
             pos.append((
                 a.get_position(True).frozen(),
@@ -3172,9 +3177,12 @@ def _update_view(self):
         if pos is None:
             return
         for i, a in enumerate(self.canvas.figure.get_axes()):
-            xmin, xmax, ymin, ymax = lims[i]
-            a.set_xlim((xmin, xmax))
-            a.set_ylim((ymin, ymax))
+            try:
+                a.restore_view(lims[i])
+            except NotImplementedError:
+                xmin, xmax, ymin, ymax = lims[i]
+                a.set_xlim((xmin, xmax))
+                a.set_ylim((ymin, ymax))
             # Restore both the original and modified positions
             a.set_position(pos[i][0], 'original')
             a.set_position(pos[i][1], 'active')
diff --git a/lib/matplotlib/backend_tools.py b/lib/matplotlib/backend_tools.py
@@ -473,9 +473,12 @@ def update_view(self):
         if pos is None:
             return
         for i, a in enumerate(self.figure.get_axes()):
-            xmin, xmax, ymin, ymax = lims[i]
-            a.set_xlim((xmin, xmax))
-            a.set_ylim((ymin, ymax))
+            try:
+                a.restore_view(lims[i])
+            except NotImplementedError:
+                xmin, xmax, ymin, ymax = lims[i]
+                a.set_xlim((xmin, xmax))
+                a.set_ylim((ymin, ymax))
             # Restore both the original and modified positions
             a.set_position(pos[i][0], 'original')
             a.set_position(pos[i][1], 'active')
@@ -488,9 +491,14 @@ def push_current(self):
         lims = []
         pos = []
         for a in self.figure.get_axes():
-            xmin, xmax = a.get_xlim()
-            ymin, ymax = a.get_ylim()
-            lims.append((xmin, xmax, ymin, ymax))
+            try:
+                view = a.save_view()
+            except NotImplementedError:
+                xmin, xmax = a.get_xlim()
+                ymin, ymax = a.get_ylim()
+                lims.append((xmin, xmax, ymin, ymax))
+            else:
+                lims.append(view)
             # Store both the original and modified positions
             pos.append((
                 a.get_position(True).frozen(),
