Adds vectors as lines functionality

glue_jupyter/bqplot/scatter/layer_artist.py

@@ -128,6 +128,7 @@ def __init__(self, view, viewer_state, layer_state=None, layer=None):
 
         # Vectors
 
+        self.vector_lines = lines_cls(scales=self.view.scales, x=[0.], y=[0.])
         self.scale_size_vector = bqplot.LinearScale(min=0, max=1)
         self.scale_color_vector = bqplot.ColorScale()
         self.scale_rotation_vector = bqplot.LinearScale(min=-np.pi, max=np.pi)
@@ -345,6 +346,12 @@ def _update_visual_attributes(self, changed, force=False):
             and self.state.vx_att is not None
             and self.state.vy_att is not None
         ):
+            vector_line_coords = self._build_line_vector_points()
+            x_vector_coords = vector_line_coords[:,0]
+            y_vector_coords = vector_line_coords[:,1]
+            self.vector_lines.x = x_vector_coords
+            self.vector_lines.y = y_vector_coords
+            self.line_mark.colors = [color2hex(self.state.color)]
 
             if self.state.cmap_mode == "Fixed":
                 breakpoint()
@@ -360,7 +367,8 @@ def _update_visual_attributes(self, changed, force=False):
                 self.scale_color_vector.max = float_or_none(self.state.cmap_vmax)
 
 
-        for mark in [self.scatter_mark, self.line_mark_gl, self.line_mark, self.vector_mark, self.density_mark]:
+        for mark in [self.scatter_mark, self.line_mark_gl, self.line_mark,
+                     self.vector_mark, self.vector_lines,  self.density_mark]:
 
             if mark is None:
                 continue
@@ -447,3 +455,30 @@ def _update_zorder(self, *args):
             for item in (layer.density_mark, layer.scatter_mark, layer.line_mark_gl,
                          layer.line_mark, layer.vector_mark)
         ]
+
+    def _build_line_vector_points(self):
+        """
+        Function builds an array of coordinate pairs separated by nans for plotting individual lines
+        to replicate vector behaviour
+        """
+        x = self._viewer_state.x_att
+        y = self._viewer_state.y_att
+        vx = self._viewer_state.vx_att
+        vy = self._viewer_state.vy_att
+
+        point_pairs = []
+        for row in range(0, len(x)):
+            x2 = x[row] + vx[row]
+            y2 = y[row] + yx[row]
+            point_1 = [x[row], y[row]]
+            point_pairs.append(point_1)
+            point_2 = [x2[row], y2[row]]
+            point_pairs.append(point_2)
+            point_3 = [np.nan, np.nan]
+            point_pairs.append(point_3)
+
+        return np.array(point_pairs)
+
+
+
+