pygfx · schlegelp · May 8, 2024 · May 8, 2024 · Mar 5, 2025
@@ -0,0 +1,93 @@
+"""
+Selection Helper
+=================
+
+Example demonstration how to use the selection helper
+to select data points:
+ - shift-click and drag the mouse to select points
+ - shift-control-click (shift-command-click on macs) to add points to the selection
+ - double click to deselect all points
+
+"""
+
+# sphinx_gallery_pygfx_docs = 'screenshot'
+# sphinx_gallery_pygfx_test = 'run'
+
+import numpy as np
+from wgpu.gui.auto import WgpuCanvas, run
+import pygfx as gfx
+import pylinalg as la
+
+
+canvas = WgpuCanvas()
+renderer = gfx.renderers.WgpuRenderer(canvas)
+scene = gfx.Scene()
+
+xx = np.random.rand(10)
+yy = np.random.rand(10)
+
+colors = np.ones((10, 4), dtype=np.float32)
+colors[:, 0] = 0
+
+geometry = gfx.Geometry(positions=[(x, y, 0) for x, y in zip(xx, yy)], colors=colors)
+ob = gfx.Points(
+    geometry, gfx.PointsMaterial(size=20, pick_write=True, color_mode="vertex")
+)
+scene.add(ob)
+
+camera = gfx.OrthographicCamera(120, 120)
+camera.show_object(ob)
+
+selected = np.zeros(len(xx), dtype=bool)
+
+
+def update_selection(sel):
+    """Highlight selected points."""
+    # Get the world coordinates of the points
+    pos_world = la.vec_transform(ob.geometry.positions.data, ob.world.matrix)
+
+    # Check if the points are inside the selection box
+    inside = sel.is_inside(pos_world)
+
+    # Update selection
+    select(inside, additive="Control" in sel._event_modifiers)
+
+
+def select(new_selected, additive=False):
+    """Select given points."""
+    # See if we actually need to change any colors
+    if any(selected != new_selected):
+        if additive:
+            selected[:] = selected | new_selected
+        else:
+            selected[:] = new_selected
+        ob.geometry.colors.data[:, :] = [0, 1, 1, 1]  # reset to cyan
+        if any(selected):
+            ob.geometry.colors.data[selected, :] = [1, 1, 0, 1]  # set to yellow
+        ob.geometry.colors.update_range()
+
+        # We need to request a redraw to make sure the colors are updated
+        canvas.request_draw(lambda: renderer.render(scene, camera))
+
+
+def deselect_all():
+    """Deselect all points."""
+    select(np.zeros(len(xx), dtype=bool))
+
+
+selection = gfx.SelectionGizmo(
+    renderer=renderer,
+    camera=camera,
+    scene=scene,
+    show_info=True,  # set to false to hide info text
+    debug=False,  # set to true to get debug output
+    callback_during_drag=update_selection,
+    callback_after_drag=update_selection,
+)
+
+renderer.add_event_handler(lambda x: deselect_all(), "double_click")
+
+
+if __name__ == "__main__":
+    canvas.request_draw(lambda: renderer.render(scene, camera))
+    run()
@@ -27,6 +27,7 @@
 from ._grid import GridHelper
 from ._box import BoxHelper
 from ._gizmo import TransformGizmo
+from ._selection import SelectionGizmo
 from ._lights import (
     PointLightHelper,
     DirectionalLightHelper,