removed alpha from base class

src/biaplotter/_tests/test_artists.py

@@ -62,12 +62,19 @@ def on_color_indices_changed(color_indices):
     assert np.all(sizes == np.linspace(1, 10, size))
 
     # Test size reset when new data is set
-    new_data = np.random.rand(size, 2)
-    scatter.data = new_data
-    assert scatter.size == 50.0  # that's the default
+    scatter.data = np.random.rand(size//2, 2)
+    assert np.all(scatter.size == 50.0)  # that's the default
     sizes = scatter._scatter.get_sizes()
     assert np.all(sizes == 50.0)
 
+    # test alpha
+    scatter.alpha = 0.5
+    assert np.all(scatter._scatter.get_alpha() == 0.5)
+
+    # test alpha reset when new data is set
+    scatter.data = np.random.rand(size, 2)
+    assert np.all(scatter._scatter.get_alpha() == 1.0)
+
 
 def test_histogram2d():
     # Inputs

src/biaplotter/artists.py

@@ -129,6 +129,7 @@
         #: Stores the scatter plot matplotlib object
         self._scatter = None
         self.data = data
+        self._alpha = 1  # Default alpha
         self._size = 50  # Default size
         self.draw()  # Initial draw of the scatter plot
 
@@ -152,38 +153,42 @@
 
     @data.setter
     def data(self, value: np.ndarray):
-        """Sets the data for the scatter plot, updating the display as needed."""
-        if value is None:
-            return
-        if len(value) == 0:
+        """Sets the data for the scatter plot, resetting other properties to defaults."""
+        if value is None or len(value) == 0:
             return
+
+        if self._data is not None:
+            data_length_changed = len(value) != len(self._data)
+        else:
+            data_length_changed = True
         self._data = value
-        # emit signal
+
+        # Emit the data changed signal
         self.data_changed_signal.emit(self._data)
-        if self._scatter is None:
-            self._scatter = self.ax.scatter(value[:, 0], value[:, 1], s=self._size)
-            self.color_indices = 0  # Set default color index
-        else:
-            # If the scatter plot already exists, just update its data
-            self._scatter.set_offsets(value)
-
-        if self._color_indices is None:
-            self.color_indices = 0  # Set default color index
+
+        if self._scatter is None or data_length_changed:
+            # Create the scatter plot if it doesn't exist yet
+            if self._scatter is not None:
+                self._scatter.remove()
+
+            # Create a new scatter plot with the updated data
+            self._scatter = self.ax.scatter(self._data[:, 0], self._data[:, 1])
+            self.size = 50  # Default size
+            self.alpha = 1  # Default alpha
+            self.color_indices = np.zeros(len(value), dtype=int)  # Default color indices
         else:
-            # Update colors if color indices are set, resize if data shape has changed
-            color_indices_size = len(self._color_indices)
-            color_indices = np.resize(self._color_indices, self._data.shape[0])
-            if len(color_indices) > color_indices_size:
-                # fill with zeros where new data is larger
-                color_indices[color_indices_size:] = 0
-            self.color_indices = color_indices
-        self.size = 50
+            self._scatter.set_offsets(value)  #  somehow resets the size and alpha
+            self.color_indices = self._color_indices
+            self.size = self._size
+            self.alpha = self._alpha
 
+        # Adjust the axes limits based on the new data
         x_margin = 0.05 * (np.max(value[:, 0]) - np.min(value[:, 0]))
         y_margin = 0.05 * (np.max(value[:, 1]) - np.min(value[:, 1]))
         self.ax.set_xlim(np.min(value[:, 0]) - x_margin, np.max(value[:, 0]) + x_margin)
         self.ax.set_ylim(np.min(value[:, 1]) - y_margin, np.max(value[:, 1]) + y_margin)
 
+        # Redraw the plot
         self.draw()
 
     @property
@@ -244,6 +249,30 @@
         self.color_indices_changed_signal.emit(self._color_indices)
         self.draw()
 
+    @property
+    def alpha(self) -> Union[float, np.ndarray]:
+        """Gets or sets the alpha value of the scatter plot.
+
+        Triggers a draw idle command.
+
+        Returns
+        -------
+        alpha : float
+            alpha value of the scatter plot.
+        """
+        return self._scatter.get_alpha()
+
+    @alpha.setter
+    def alpha(self, value: Union[float, np.ndarray]):
+        """Sets the alpha value of the scatter plot."""
+        self._alpha = value
+
+        if np.isscalar(value):
+            value = np.ones(len(self._data)) * value
+        if self._scatter is not None:
+            self._scatter.set_alpha(value)
+        self.draw()
+
     @property
     def size(self) -> Union[float, np.ndarray]:
         """Gets or sets the size of the points in the scatter plot.