Start to work on animations and use tight_layout()

replot/__init__.py

@@ -14,6 +14,7 @@ try:
     os.environ["DISPLAY"]
 except KeyError:
     mpl.use("agg")
+import matplotlib.animation as animation
 import matplotlib.pyplot as plt
 import numpy as np
 import palettable
@@ -113,6 +114,9 @@ class Figure():
         # Working attributes
         self.figure = None
         self.axes = None
+        self.animation = {"type": False,
+                          "args": (), "kwargs": {},
+                          "persist": []}
 
     def __enter__(self):
         return self
@@ -143,15 +147,21 @@ class Figure():
         if len(args) == 0 and self.savepath is not None:
             args = (self.savepath,)
 
-        figure = self.render()
-        figure.savefig(*args, **kwargs)
+        self.render()
+        if self.figure is not None:
+            self.figure.savefig(*args, **kwargs)
+        else:
+            raise exc.InvalidFigure("Invalid figure.")
 
     def show(self):
         """
         Render and show the :class:`Figure` object.
         """
-        figure = self.render()
-        figure.show()
+        self.render()
+        if self.figure is not None:
+            self.figure.show()
+        else:
+            raise exc.InvalidFigure("Invalid figure.")
 
     def set_grid(self, grid_description=None,
                  height=None, width=None, ignore_groups=False,
@@ -306,6 +316,10 @@ class Figure():
                     the axes labels as well.
             - ``rotate`` (angle in degrees) rotate the plot by the angle in \
                     degrees. Leave the labels untouched.
+            - ``frame`` to specify a frame on which the plot should appear \
+                    when calling ``animate`` afterwards. Default behavior is \
+                    to increase the frame number between each plots. Frame \
+                    count starts at 0.
 
         .. note:: Note that this API call considers list of tuples as \
                 list of (x, y) coordinates to plot, contrary to standard \
@@ -376,9 +390,10 @@ class Figure():
 
         # Add the plot to the correct group
         if "group" in custom_kwargs:
-            self.plots[custom_kwargs["group"]].append(plot_)
+            group_ = custom_kwargs["group"]
         else:
-            self.plots[_DEFAULT_GROUP].append(plot_)
+            group_ = _DEFAULT_GROUP
+        self.plots[group_].append(plot_)
 
         # Automatically set the legend if label is found
         # (only do it if legend is not explicitly suppressed)
@@ -407,6 +422,20 @@ class Figure():
         kwargs["logscale"] = "loglog"
         self.plot(*args, **kwargs)
 
+    def animate(self, *args, **kwargs):
+        """
+        Create an animation.
+
+        You can either:
+            - pass it a function TODO
+            - use it directly without arguments to create an animation from \
+                    the previously plot commands.
+        """
+        # TODO
+        self.animation["type"] = "gif"
+        self.animation["args"] = args
+        self.animation["kwargs"] = kwargs
+
     def _legend(self, axis, overload_legend=None):
         """
         Helper function to handle ``legend`` attribute. It places the legend \
@@ -454,11 +483,18 @@ class Figure():
             figure, axis = plt.subplots()
             # Set the palette for the subplot
             axis.set_prop_cycle(
-                self._build_cycler_palette(sum([len(i) for i in self.plots])))
+                self._build_cycler_palette(sum([len(i)
+                                                for i in self.plots.values()]))
+            )
             # Set the axis for every subplot
             for subplot in self.plots:
                 axes[subplot] = axis
-            return figure, axes
+
+            # Set attributes
+            self.figure = figure
+            self.axes = axes
+            # Return
+            return
         elif self.grid is None:
             # If no grid is provided, create an auto grid for the figure.
             self._set_auto_grid()
@@ -590,6 +626,57 @@ class Figure():
             if self.figure is None or self.axes is None:
                 # Create figure if necessary
                 self._grid()
+
+            if self.animation["type"] is False:
+                self._render_no_animation()
+            elif self.animation["type"] == "gif":
+                self._render_gif_animation()
+            elif self.animation["type"] == "animation":
+                # TODO
+                return None
+            else:
+                return None
+        self.figure.tight_layout(pad=1)
+
+    def _render_gif_animation(self):
+        """
+        Handle the render of a GIF-like animation, cycling through the plots.
+
+        :returns: A :mod:`matplotlib` figure.
+        """
+        # Init
+        # TODO
+        self.axes[_DEFAULT_GROUP].set_xlim((-2, 2))
+        self.axes[_DEFAULT_GROUP].set_ylim((-2, 2))
+        line, = self.axes[_DEFAULT_GROUP].plot([], [])
+        # Define an animation function (closure)
+        def animate(i):
+            # TODO
+            x = np.linspace(0, 2, 1000)
+            y = np.sin(2 * np.pi * (x - 0.01 * i))
+            line.set_data(x, y)
+            return line,
+        # Set default kwargs
+        default_args = (self.figure, animate)
+        default_kwargs = {
+            "frames": 200,
+            "interval": 20,
+            "blit": True,
+        }
+        # Update with overloaded arguments
+        default_args = default_args + self.animation["args"]
+        default_kwargs.update(self.animation["kwargs"])
+        # Keep track of animation object, as it has to persist
+        self.animation["persist"] = [
+            animation.FuncAnimation(*default_args, **default_kwargs)]
+        return self.figure
+
+    def _render_no_animation(self):
+        """
+        Handle the render of the figure when no animation is used.
+
+        :returns: A :mod:`matplotlib` figure.
+        """
         # Add plots
         for group_ in self.plots:
             # Get the axis corresponding to current group
@@ -829,6 +916,12 @@ def _handle_custom_plot_arguments(kwargs):
         # Convert angle to radians
         custom_kwargs["rotate"] = kwargs["rotate"] * np.pi / 180
         del kwargs["rotate"]
+    # Handle "frame" argument
+    if "frame" in kwargs:
+        custom_kwargs["frame"] = kwargs["frame"]
+        del kwargs["frame"]
+    else:
+        custom_kwargs["frame"] = 0
     return (kwargs, custom_kwargs)
 
 

replot/exceptions.py

@@ -15,3 +15,10 @@ class InvalidParameterError(BaseException):
     Exception raised when an invalid parameter is provided.
     """
     pass
+
+
+class InvalidFigure(BaseException):
+    """
+    Exception raised when a figure is invalid and cannot be shown.
+    """
+    pass