fastplotlib · kushalkolar · Sep 29, 2025 · Sep 29, 2025 · Sep 29, 2025 · Sep 30, 2025
@@ -2,7 +2,8 @@
 Linear Selectors
 ================
 
-Example showing how to use a `LinearSelector` with lines and line collections.
+Example showing how to use a `LinearSelector` with lines and line collections. The linear selector is the yellow
+vertical line.
 """
 
 # test_example = true

@@ -2,8 +2,9 @@
 Linear Selectors Image
 ======================
 
-Example showing how to use a `LinearSelector` to selector rows or columns of an image. The subplot on the right
-displays the data for the selector row and column.
+Example showing how to use a `LinearSelector` to select rows or columns of an image. The subplot on the right
+displays the data for the selector row and column. Move the selectors independently or click the middle mouse
+button to move both selectors to the clicked location.
 """
 
 # test_example = false
@@ -24,10 +25,10 @@
 image = figure[0, 0].add_image(image_data)
 
 # add a row selector
-image_row_selector = image.add_linear_selector(axis="y")
+image_row_selector = image.add_linear_selector(axis="y", edge_color="cyan")
 
 # add column selector
-image_col_selector = image.add_linear_selector()
+image_col_selector = image.add_linear_selector(edge_color="cyan")
 
 # make a line to indicate row data
 line_image_row = figure[0, 1].add_line(image.data[0])

@@ -132,6 +132,9 @@ def set_x_val(ev):
 sine_selector.add_event_handler(set_x_val, "selection")
 cosine_selector.add_event_handler(set_x_val, "selection")
 
+# set initial position of the selector so it's not just overlapping the y-axis
+sine_selector.selection = 100
+
 figure.show()
 
 

@@ -64,9 +64,9 @@ def set_value(self, selector, value: float):
         elif self._axis == "y":
             dim = 1
 
-        for edge in selector._edges:
-            edge.geometry.positions.data[:, dim] = value
-            edge.geometry.positions.update_range()
+        edge = selector._edges[0]
+        edge.geometry.positions.data[:, dim] = value
+        edge.geometry.positions.update_range()
 
         self._value = value
 
@@ -152,10 +152,10 @@ def set_value(self, selector, value: Sequence[float]):
             selector.fill.geometry.positions.data[mesh_masks.x_right] = value[1]
 
             # change x position of the left edge line
-            selector.edges[0].geometry.positions.data[:, 0] = value[0]
+            selector._edges[0].geometry.positions.data[:, 0] = value[0]
 
             # change x position of the right edge line
-            selector.edges[1].geometry.positions.data[:, 0] = value[1]
+            selector._edges[1].geometry.positions.data[:, 0] = value[1]
 
         elif self.axis == "y":
             # change bottom y position of the fill mesh
@@ -165,18 +165,18 @@ def set_value(self, selector, value: Sequence[float]):
             selector.fill.geometry.positions.data[mesh_masks.y_top] = value[1]
 
             # change y position of the bottom edge line
-            selector.edges[0].geometry.positions.data[:, 1] = value[0]
+            selector._edges[0].geometry.positions.data[:, 1] = value[0]
 
             # change y position of the top edge line
-            selector.edges[1].geometry.positions.data[:, 1] = value[1]
+            selector._edges[1].geometry.positions.data[:, 1] = value[1]
 
         self._value = value
 
         # send changes to GPU
         selector.fill.geometry.positions.update_range()
 
-        selector.edges[0].geometry.positions.update_range()
-        selector.edges[1].geometry.positions.update_range()
+        selector._edges[0].geometry.positions.update_range()
+        selector._edges[1].geometry.positions.update_range()
 
         # send event
         if len(self._event_handlers) < 1: