fastplotlib · clewis7 · May 22, 2025 · May 20, 2025 · May 20, 2025 · May 20, 2025
@@ -7,6 +7,7 @@
 
 
 __all__ = [
+    "Graphic",
     "LineGraphic",
     "ScatterGraphic",
     "ImageGraphic",

@@ -7,7 +7,7 @@
 from ._rect import RectManager
 
 
-class UnderlayCamera(pygfx.Camera):
+class ScreenSpaceCamera(pygfx.Camera):
     """
     Same as pygfx.ScreenCoordsCamera but y-axis is inverted.
 

@@ -19,7 +19,7 @@
 )
 from ._utils import controller_types as valid_controller_types
 from ._subplot import Subplot
-from ._engine import GridLayout, WindowLayout, UnderlayCamera
+from ._engine import GridLayout, WindowLayout, ScreenSpaceCamera
 from .. import ImageGraphic
 
 
@@ -409,10 +409,14 @@ def __init__(
                 canvas_rect=self.get_pygfx_render_area(),
             )
 
-        self._underlay_camera = UnderlayCamera()
-
+        # underlay render pass
+        self._underlay_camera = ScreenSpaceCamera()
         self._underlay_scene = pygfx.Scene()
 
+        # overlay render pass
+        self._overlay_camera = ScreenSpaceCamera()
+        self._overlay_scene = pygfx.Scene()
+
         for subplot in self._subplots.ravel():
             self._underlay_scene.add(subplot.frame._world_object)
 
@@ -492,6 +496,9 @@ def _render(self, draw=True):
         for subplot in self:
             subplot._render()
 
+        # overlay render pass
+        self.renderer.render(self._overlay_scene, self._overlay_camera, flush=False)
+
         self.renderer.flush()
 
         # call post-render animate functions

@@ -1 +1,2 @@
 from ._histogram_lut import HistogramLUTTool
+from ._tooltip import Tooltip
@@ -0,0 +1,177 @@
+from functools import partial
+
+import numpy as np
+import pygfx
+from .. import ScatterGraphic
+
+from ..graphics import LineGraphic, ImageGraphic, TextGraphic
+
+
+class MeshMasks:
+    """Used set the x0, x1, y0, y1 positions of the plane mesh"""
+
+    x0 = np.array(
+        [
+            [False, False, False],
+            [True, False, False],
+            [False, False, False],
+            [True, False, False],
+        ]
+    )
+
+    x1 = np.array(
+        [
+            [True, False, False],
+            [False, False, False],
+            [True, False, False],
+            [False, False, False],
+        ]
+    )
+
+    y0 = np.array(
+        [
+            [False, True, False],
+            [False, True, False],
+            [False, False, False],
+            [False, False, False],
+        ]
+    )
+
+    y1 = np.array(
+        [
+            [False, False, False],
+            [False, False, False],
+            [False, True, False],
+            [False, True, False],
+        ]
+    )
+
+
+masks = MeshMasks
+
+
+class Tooltip:
+    def __init__(self):
+        self._text = pygfx.Text(
+            text="",
+            font_size=12,
+            screen_space=False,
+            anchor="bottom-left",
+            material=pygfx.TextMaterial(
+                color="w",
+                outline_color="w",
+                outline_thickness=0.0,
+                pick_write=False,
+            ),
+        )
+
+        geometry = pygfx.plane_geometry(1, 1)
+        material = pygfx.MeshBasicMaterial(color=(0.1, 0.1, 0.3, 1.))
+        self._plane = pygfx.Mesh(geometry, material)
+        # else text not visible
+        self._plane.world.z = 0.5
+
+        # line to outline the mesh
+        self._line = pygfx.Line(
+            geometry=pygfx.Geometry(
+                    positions=np.array([
+                        [0, 0, 0],
+                        [0, 0, 0],
+                        [0, 0, 0],
+                        [0, 0, 0],
+                        [0, 0, 0],
+                    ], dtype=np.float32)
+            ),
+            material=pygfx.LineThinMaterial(
+                thickness=1.0, color=(0.8, 0.8, 1.0, 1.0)
+            )
+        )
+
+
+        self._world_object = pygfx.Group()
+        self._world_object.add(self._plane, self._text, self._line)
+
+        # padded to bbox so the background box behind the text extends a bit further
+        # making the text easier to read
+        self._padding = np.array(
+            [[5, 5, 0],
+             [-5, -5, 0]],
+            dtype=np.float32
+
+        )
+
+    def _set_position(self, pos: tuple[float, float]):
+        """
+        Set the position of the tooltip
+
+        Parameters
+        ----------
+        pos: [float, float]
+            position in screen space
+
+        """
+        # need to flip due to inverted y
+        x, y = pos[0], pos[1]
+
+        self._text.world.position = (x, -y, 0)
+
+        bbox = self._text.get_world_bounding_box() - self._padding
+        [[x0, y0, _], [x1, y1, _]] = bbox
+
+        self._plane.geometry.positions.data[masks.x0] = x0
+        self._plane.geometry.positions.data[masks.x1] = x1
+        self._plane.geometry.positions.data[masks.y0] = y0
+        self._plane.geometry.positions.data[masks.y1] = y1
+
+        self._plane.geometry.positions.update_range()
+
+        # line points
+        pts = [
+            [x0, y0],
+            [x0, y1],
+            [x1, y1],
+            [x1, y0],
+            [x0, y0]
+        ]
+
+        self._line.geometry.positions.data[:, :2] = pts
+        self._line.geometry.positions.update_range()
+
+    def _event_handler(self, display_property, ev: pygfx.PointerEvent):
+        if isinstance(ev.graphic, ImageGraphic):
+            col, row = ev.pick_info["index"]
+            info = ev.graphic.data[row, col]
+            self._text.set_text(str(info))
+
+        elif isinstance(ev.graphic, (LineGraphic, ScatterGraphic)):
+            index = ev.pick_info["vertex_index"]
+            info = ev.graphic.data[index]
+            self._text.set_text(str(info))
+
+        self._set_position((ev.x, ev.y))
+
+    def _clear(self, ev):
+        self._text.set_text("")
+
+        self._text.world.position = (-1, -1, 0)
+
+        self._plane.geometry.positions.data[masks.x0] = -1
+        self._plane.geometry.positions.data[masks.x1] = -1
+        self._plane.geometry.positions.data[masks.y0] = -1
+        self._plane.geometry.positions.data[masks.y1] = -1
+
+        self._plane.geometry.positions.update_range()
+
+        # line points
+        self._line.geometry.positions.data[:, :2] = -1
+        self._line.geometry.positions.update_range()
+
+    def register_graphic(
+        self,
+        graphic,
+        event_type: str = "pointer_move",
+        display_property: str = "data",
+        formatter: callable = None,
+    ):
+        graphic.add_event_handler(partial(self._event_handler, display_property), event_type)
+        graphic.add_event_handler(self._clear, "pointer_leave")
Original file line number	Diff line number	Diff line change
		@@ -1 +1,2 @@
		from ._histogram_lut import HistogramLUTTool
		from ._tooltip import Tooltip