lkeegan · Jul 21, 2025 · Jul 22, 2025 · Jul 23, 2025 · Jul 23, 2025 · Sep 29, 2025
@@ -0,0 +1,66 @@
+"""
+LinearRegionSelectors with ScatterGraphic
+=========================================
+
+Example showing how to use a `LinearRegionSelector` with a scatter plot. We demonstrate two use cases, a horizontal
+LinearRegionSelector which selects along the x-axis and a vertical selector which moves along the y-axis.
+"""
+
+# test_example = false
+# sphinx_gallery_pygfx_docs = 'screenshot'
+
+import fastplotlib as fpl
+import numpy as np
+
+# names for out subplots
+names = [
+    ["scatter x", "scatter y"],
+    ["zoomed x region", "zoomed y region"]
+]
+
+# 2 rows, 2 columns
+figure = fpl.Figure(
+    (2, 2),
+    size=(700, 560),
+    names=names,
+)
+
+scatter_x_data = (100*np.random.random_sample(size=(500, 2))).astype(np.float32)
+scatter_y_data = (100*np.random.random_sample(size=(500, 2))).astype(np.float32)
+
+# plot scatter data
+scatter_x = figure[0, 0].add_scatter(scatter_x_data)
+scatter_y = figure[0, 1].add_scatter(scatter_y_data)
+
+# add linear selectors
+selector_x = scatter_x.add_linear_region_selector((0, 100))  # default axis is "x"
+selector_y = scatter_y.add_linear_region_selector(axis="y")
+
+@selector_x.add_event_handler("selection")
+def set_zoom_x(ev):
+    """sets zoomed x selector data"""
+    selected_data = ev.get_selected_data()
+    figure[1, 0].clear()
+    figure[1, 0].add_scatter(selected_data, sizes=10)
+    figure[1, 0].auto_scale()
+
+
+@selector_y.add_event_handler("selection")
+def set_zoom_y(ev):
+    """sets zoomed y selector data"""
+    selected_data = ev.get_selected_data()
+    figure[1, 1].clear()
+    figure[1, 1].add_scatter(selected_data, sizes=10)
+    figure[1, 1].auto_scale()
+
+# set initial selection
+selector_x.selection = (30, 60)
+selector_y.selection = (30, 60)
+
+figure.show(maintain_aspect=False)
+
+# NOTE: fpl.loop.run() should not be used for interactive sessions
+# See the "JupyterLab and IPython" section in the user guide
+if __name__ == "__main__":
+    print(__doc__)
+    fpl.loop.run()
@@ -0,0 +1,49 @@
+"""
+Rectangle Selectors with ScatterGraphic
+=======================================
+
+Example showing how to use a `RectangleSelector` with a scatter plot.
+"""
+
+# test_example = false
+# sphinx_gallery_pygfx_docs = 'screenshot'
+
+import numpy as np
+import fastplotlib as fpl
+
+# create a figure
+figure = fpl.Figure(
+    size=(700, 560)
+)
+
+xys = (100 * np.random.random_sample(size=(200, 2))).astype(np.float32)
+
+# add image
+scatter = figure[0, 0].add_scatter(xys, cmap="jet", sizes=4)
+
+# add rectangle selector to image graphic
+rectangle_selector = scatter.add_rectangle_selector()
+
+# add event handler to highlight selected indices
+@rectangle_selector.add_event_handler("selection")
+def color_indices(ev):
+    scatter.cmap = "jet"
+    scatter.sizes = 4
+    ixs = ev.get_selected_indices()
+    if ixs.size == 0:
+        return
+    scatter.colors[ixs] = 'w'
+    scatter.sizes[ixs] = 8
+
+
+# manually move selector to make a nice gallery image :D
+rectangle_selector.selection = (20, 40, 40, 60)
+
+
+figure.show()
+
+# NOTE: fpl.loop.run() should not be used for interactive sessions
+# See the "JupyterLab and IPython" section in the user guide
+if __name__ == "__main__":
+    print(__doc__)
+    fpl.loop.run()
@@ -283,7 +283,6 @@ def add_rectangle_selector(
         """
         # computes args to create selectors
         n_datapoints = self.data.value.shape[0]
-        value_25p = int(n_datapoints / 4)
 
         # remove any nans
         data = self.data.value[~np.any(np.isnan(self.data.value), axis=1)]
@@ -293,13 +292,15 @@ def add_rectangle_selector(
 
         ymin = np.floor(y_axis_vals.min()).astype(int)
         ymax = np.ceil(y_axis_vals.max()).astype(int)
+        xmin = np.floor(x_axis_vals.min()).astype(int)
+        xmax = np.ceil(x_axis_vals.max()).astype(int)
 
         # default selection is 25% of the image
         if selection is None:
-            selection = (x_axis_vals[0], x_axis_vals[value_25p], ymin, ymax)
+            selection = (xmin, xmin + 0.25 * (xmax - xmin), ymin, ymax)
 
         # min/max limits
-        limits = (x_axis_vals[0], x_axis_vals[-1], ymin * 1.5, ymax * 1.5)
+        limits = (xmin, xmax, ymin, ymax)
 
         selector = RectangleSelector(
             selection=selection,
@@ -318,7 +319,6 @@ def _get_linear_selector_init_args(
     ) -> tuple[tuple[float, float], tuple[float, float], float, float]:
         # computes args to create selectors
         n_datapoints = self.data.value.shape[0]
-        value_25p = int(n_datapoints / 4)
 
         # remove any nans
         data = self.data.value[~np.any(np.isnan(self.data.value), axis=1)]
@@ -333,8 +333,13 @@ def _get_linear_selector_init_args(
             axis_vals = data[:, 1]
             magn_vals = data[:, 0]
 
-        bounds_init = axis_vals[0], axis_vals[value_25p]
-        limits = axis_vals[0], axis_vals[-1]
+        axis_vals_min = np.floor(axis_vals.min()).astype(int)
+        axis_vals_max = np.floor(axis_vals.max()).astype(int)
+
+        bounds_init = axis_vals_min, axis_vals_min + 0.25 * (
+            axis_vals_max - axis_vals_min
+        )
+        limits = axis_vals_min, axis_vals_max
 
         # width or height of selector
         size = int(np.ptp(magn_vals) * 1.5 + padding)

@@ -301,6 +301,9 @@ def get_selected_data(
                 # slice with min, max is faster than using all the indices
                 return source.data[s]
 
+        if "Scatter" in source.__class__.__name__:
+            return source.data[ixs]
+
         if "Image" in source.__class__.__name__:
             s = slice(ixs[0], ixs[-1] + 1)
 

@@ -454,7 +454,10 @@ def get_selected_indices(
             row_ixs = np.arange(ymin, ymax, dtype=int)
             return row_ixs, col_ixs
 
-        if "Line" in source.__class__.__name__:
+        if (
+            "Line" in source.__class__.__name__
+            or "Scatter" in source.__class__.__name__
+        ):
             if isinstance(source, GraphicCollection):
                 ixs = list()
                 for g in source.graphics: