Plot arcs method

examples/pitch_plots/plot_arcs_around_goals.py

@@ -0,0 +1,42 @@
+"""
+==========================
+Plotting arcs around goals
+==========================
+
+This example shows how to plot arcs around goals at specified distances on various pitch types.
+"""
+from mplsoccer import Pitch, VerticalPitch
+import matplotlib.pyplot as plt
+
+
+def plot_arcs_around_goals_on_pitches(pitch_cls):
+    fig, axes = plt.subplots(4, 2, figsize=(12, 14))
+    axes = axes.ravel()
+    pitch_types = ['statsbomb', 'opta', 'tracab', 'skillcorner', 'wyscout',
+                'metricasports', 'uefa', 'custom']
+
+    placements = ('top', 'bottom') if pitch_cls == VerticalPitch else ('left', 'right')
+    colors = ('red', 'blue')
+    for idx, pt in enumerate(pitch_types):
+        if pt in ['tracab', 'metricasports', 'custom', 'skillcorner']:
+            pitch = pitch_cls(pitch_type=pt, pitch_length=105, pitch_width=68)
+        else:
+            pitch = pitch_cls(pitch_type=pt)
+
+        pitch.draw(axes[idx])
+        axes[idx].set_title(pt, fontsize=20, c='black', pad=15)
+        for radius_meters in (5, 10, 20, 30):
+            for color, placement in zip(colors, placements):
+                pitch.add_arc_around_goal(axes[idx], radius_meters, placement=placement, color=color)
+    return fig, axes
+
+
+##############################################################################
+# Horizontal pitches
+
+plot_arcs_around_goals_on_pitches(Pitch)
+
+##############################################################################
+# Vertical pitches
+
+plot_arcs_around_goals_on_pitches(VerticalPitch)

mplsoccer/pitch.py

@@ -114,6 +114,70 @@ def _reverse_vertices_if_vertical(vert):
     def _reverse_annotate_if_vertical(annotate):
         return annotate
 
+    def add_arc_around_goal(self, ax, radius_meters, placement='left', **kwargs):
+        """Add an arc to the pitch centred on one of the goals.
+
+        Parameters
+        ----------
+        ax : matplotlib axis
+            A matplotlib.axes.Axes to draw the arc on.
+        radius_meters : float
+            The radius of the arc in meters.
+        placement : str, default 'left'
+            Which side of the pitch to plot the arc. Should be either 'left' or 'right'.
+        kwargs : dict
+            Additional keyword arguments accepted by matplotlib.patches.Arc.
+
+        Returns
+        -------
+            Arc added to `ax` and None returned.
+
+        Raises
+        ------
+        ValueError
+            If `placement` is not 'left' or 'right'.
+
+        Examples
+        --------
+        >>> from mplsoccer import Pitch
+        >>> pitch = Pitch()
+        >>> fig, ax = pitch.draw()
+        >>> pitch.add_arc_around_goal(ax, radius_meters=10, placement="left")
+        >>> pitch.add_arc_around_goal(ax, radius_meters=20, placement="right", color="red")
+        """
+        xmin, xmax, ymin, ymax = self.extent
+        length_pixels = abs(xmax - xmin)
+        width_pixels = abs(ymax - ymin)
+
+        # scale down via ratio of radius to dimension
+        if self.pitch_type != 'metricasports':
+            width = 2 * length_pixels * radius_meters / self.dim.length
+            height =  2 * width_pixels * radius_meters / self.dim.width / self.dim.aspect
+            if self.pitch_type == 'tracab':
+                # has unit centimeters
+                width *= 100
+                height *= 100
+        elif self.pitch_type == 'metricasports':
+            width = 2 * length_pixels * radius_meters / self.dim.pitch_length
+            height = 2 * width_pixels * radius_meters / self.dim.pitch_width 
+
+        if self.dim.origin_center:
+            y = 0
+        else:
+            y = width_pixels / 2 - self.pad_bottom
+        if placement == 'left':
+            self._draw_arc(
+                ax, xmin + self.pad_left, y, width, height, theta1=-90, theta2=90, **kwargs
+            )
+        elif placement == 'right':
+            self._draw_arc(
+                ax, xmax - self.pad_right, y, width, height, theta1=90, theta2=270, **kwargs
+            )
+        else:
+            raise ValueError(
+                f'placement={placement} should be "left" or "right"'
+            )
+
 
 class VerticalPitch(BasePitchPlot):
 
@@ -222,3 +286,67 @@ def _reverse_vertices_if_vertical(vert):
     @staticmethod
     def _reverse_annotate_if_vertical(annotate):
         return annotate[::-1]
+
+    def add_arc_around_goal(self, ax, radius_meters, placement, **kwargs):
+        """Add an arc to the pitch centred on one of the goals.
+
+        Parameters
+        ----------
+        ax : matplotlib axis
+            A matplotlib.axes.Axes to draw the arc on.
+        radius_meters : float
+            The radius of the arc in meters.
+        placement : str, default 'top'
+            Which side of the pitch to plot the arc. Should be either 'top' or 'bottom'.
+        kwargs : dict
+            Additional keyword arguments accepted by matplotlib.patches.Arc.
+
+        Returns
+        -------
+            Arc added to `ax` and None returned.
+
+        Raises
+        ------
+        ValueError
+            If `placement` is not 'top' or 'bottom'.
+
+        Examples
+        --------
+        >>> from mplsoccer import Pitch
+        >>> pitch = Pitch()
+        >>> fig, ax = pitch.draw()
+        >>> pitch.add_arc_around_goal(ax, radius_meters=15, placement="bottom")
+        >>> pitch.add_arc_around_goal(ax, radius_meters=7, placement="top", color="blue")
+        """
+        xmin, xmax, ymin, ymax = self.extent
+        width_pixels = abs(xmax - xmin)
+        length_pixels = abs(ymax - ymin)
+
+        # scale down via ratio of radius to dimension
+        if self.pitch_type != "metricasports":
+            width = 2 * width_pixels * self.dim.aspect * radius_meters / self.dim.width
+            height = 2 * length_pixels * radius_meters / self.dim.length
+            if self.pitch_type == "tracab":
+                # has unit centimeters
+                width *= 100
+                height *= 100
+        elif self.pitch_type == "metricasports":
+            width = 2 * width_pixels * radius_meters / self.dim.pitch_width
+            height = 2 * length_pixels * radius_meters / self.dim.pitch_length
+
+        if self.dim.origin_center:
+            x = 0
+        else:
+            x = width_pixels / 2 - self.pad_left
+        if placement == 'bottom':
+            self._draw_arc(
+                ax, ymin + self.pad_bottom, x, height, width, theta1=-90, theta2=90, **kwargs
+            )
+        elif placement == 'top':
+            self._draw_arc(
+                ax, ymax - self.pad_top, x, height, width, theta1=90, theta2=270, **kwargs
+            )
+        else:
+            raise ValueError(
+                f'placement={placement} should be "top" or "bottom"'
+            )