fastplotlib · clewis7 · Mar 5, 2025 · Mar 3, 2025 · Mar 4, 2025 · Mar 4, 2025
@@ -0,0 +1,114 @@
+"""
+Unit circle
+===========
+
+Example with linear selectors on a sine and cosine function that demonstrates the unit circle.
+
+This shows how fastplotlib supports bidirectional events, drag the linear selector on the sine
+or cosine function and they will both move together.
+
+Click on the sine or cosine function to set the colormap transform to illustrate the sine or
+cosine function output values on the unit circle.
+"""
+
+# test_example = false
+# sphinx_gallery_pygfx_docs = 'screenshot'
+
+
+import numpy as np
+import fastplotlib as fpl
+
+
+# helper function to make a cirlce
+def make_circle(center, radius: float, n_points: int) -> np.ndarray:
+    theta = np.linspace(0, 2 * np.pi, n_points)
+    xs = radius * np.cos(theta)
+    ys = radius * np.sin(theta)
+
+    return np.column_stack([xs, ys]) + center
+
+
+# create a figure with 3 subplots
+figure = fpl.Figure((3, 1), names=["unit circle", "sin(x)", "cos(x)"], size=(700, 1024))
+
+# set the axes to intersect at (0, 0, 0) to better illustrate the unit circle
+for subplot in figure:
+    subplot.axes.intersection = (0, 0, 0)
+
+figure["sin(x)"].camera.maintain_aspect = False
+figure["cos(x)"].camera.maintain_aspect = False
+
+# create sine and cosine data
+xs = np.linspace(0, 2 * np.pi, 360)
+sine = np.sin(xs)
+cosine = np.cos(xs)
+
+# circle data
+circle_data = make_circle(center=(0, 0), radius=1, n_points=360)
+
+# make the circle line graphic, set the cmap transform using the sine function
+circle_graphic = figure["unit circle"].add_line(
+    circle_data, thickness=4, cmap="bwr", cmap_transform=sine
+)
+
+# line to show the circle radius
+# use it to indicate the current position of the sine and cosine selctors (below)
+radius_data = np.array([[0, 0, 0], [*circle_data[0], 0]])
+circle_radius = figure["unit circle"].add_line(
+    radius_data, thickness=6, colors="magenta"
+)
+
+# sine line graphic, cmap transform set from the sine function
+sine_graphic = figure["sin(x)"].add_line(
+    sine, thickness=10, cmap="bwr", cmap_transform=sine
+)
+
+# cosine line graphic, cmap transform set from the sine function
+# illustrates the sine function values on the cosine graphic
+cosine_graphic = figure["cos(x)"].add_line(
+    cosine, thickness=10, cmap="bwr", cmap_transform=sine
+)
+
+# add linear selectors to the sine and cosine line graphics
+sine_selector = sine_graphic.add_linear_selector()
+cosine_selector = cosine_graphic.add_linear_selector()
+
+def set_circle_cmap(ev):
+    # sets the cmap transforms
+
+    cmap_transform = ev.graphic.data[:, 1]  # y-val data of the sine or cosine graphic
+    for g in [sine_graphic, cosine_graphic]:
+        g.cmap.transform = cmap_transform
+
+    # set circle cmap transform
+    circle_graphic.cmap.transform = cmap_transform
+
+# when the sine or cosine graphic is clicked, the cmap_transform
+# of the sine, cosine and circle line graphics are all set from
+# the y-values of the clicked line
+sine_graphic.add_event_handler(set_circle_cmap, "click")
+cosine_graphic.add_event_handler(set_circle_cmap, "click")
+
+
+def set_x_val(ev):
+    # used to sync the two selectors
+    value = ev.info["value"]
+    index = ev.get_selected_index()
+
+    sine_selector.selection = value
+    cosine_selector.selection = value
+
+    circle_radius.data[1, :-1] = circle_data[index]
+
+# add same event handler to both graphics
+sine_selector.add_event_handler(set_x_val, "selection")
+cosine_selector.add_event_handler(set_x_val, "selection")
+
+figure.show()
+
+
+# NOTE: `if __name__ == "__main__"` is NOT how to use fastplotlib interactively
+# please see our docs for using fastplotlib interactively in ipython and jupyter
+if __name__ == "__main__":
+    print(__doc__)
+    fpl.loop.run()
@@ -53,6 +53,9 @@ def __init__(self, **kwargs):
         self._event_handlers = list()
         self._block_events = False
 
+        # used by @block_reentrance decorator to block re-entrance into set_value functions
+        self._reentrant_block: bool = False
+
     @property
     def value(self) -> Any:
         """Graphic Feature value, must be implemented in subclass"""
@@ -316,3 +319,33 @@ def __len__(self):
 
     def __repr__(self):
         return f"{self.__class__.__name__} buffer data:\n" f"{self.value.__repr__()}"
+
+
+def block_reentrance(set_value):
+    # decorator to block re-entrant set_value methods
+    # useful when creating complex, circular, bidirectional event graphs
+    def set_value_wrapper(self: GraphicFeature, graphic_or_key, value):
+        """
+        wraps GraphicFeature.set_value
+
+        self: GraphicFeature instance
+
+        graphic_or_key: graphic, or key if a BufferManager
+
+        value: the value passed to set_value()
+        """
+        # set_value is already in the middle of an execution, block re-entrance
+        if self._reentrant_block:
+            return
+        try:
+            # block re-execution of set_value until it has *fully* finished executing
+            self._reentrant_block = True
+            set_value(self, graphic_or_key, value)
+        except Exception as exc:
+            # raise original exception
+            raise exc  # set_value has raised. The line above and the lines 2+ steps below are probably more relevant!
+        finally:
+            # set_value has finished executing, now allow future executions
+            self._reentrant_block = False
+
+    return set_value_wrapper
@@ -1,6 +1,6 @@
 import numpy as np
 
-from ._base import GraphicFeature, FeatureEvent
+from ._base import GraphicFeature, FeatureEvent, block_reentrance
 
 
 class Name(GraphicFeature):
@@ -14,6 +14,7 @@ def __init__(self, value: str):
     def value(self) -> str:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str):
         if not isinstance(value, str):
             raise TypeError("`Graphic` name must be of type <str>")
@@ -44,6 +45,7 @@ def _validate(self, value):
     def value(self) -> np.ndarray:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: np.ndarray | list | tuple):
         self._validate(value)
 
@@ -74,6 +76,7 @@ def _validate(self, value):
     def value(self) -> np.ndarray:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: np.ndarray | list | tuple):
         self._validate(value)
 
@@ -96,6 +99,7 @@ def __init__(self, value: bool):
     def value(self) -> bool:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: bool):
         graphic.world_object.visible = value
         self._value = value
@@ -117,6 +121,7 @@ def __init__(self, value: bool):
     def value(self) -> bool:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: bool):
         self._value = value
         event = FeatureEvent(type="deleted", info={"value": value})

@@ -5,7 +5,7 @@
 import numpy as np
 
 import pygfx
-from ._base import GraphicFeature, FeatureEvent
+from ._base import GraphicFeature, FeatureEvent, block_reentrance
 
 from ...utils import (
     make_colors,
@@ -135,6 +135,7 @@ def __next__(self) -> tuple[pygfx.Texture, tuple[int, int], tuple[slice, slice]]
     def __getitem__(self, item):
         return self.value[item]
 
+    @block_reentrance
     def __setitem__(self, key, value):
         self.value[key] = value
 
@@ -159,6 +160,7 @@ def __init__(self, value: float):
     def value(self) -> float:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: float):
         vmax = graphic._material.clim[1]
         graphic._material.clim = (value, vmax)
@@ -179,6 +181,7 @@ def __init__(self, value: float):
     def value(self) -> float:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: float):
         vmin = graphic._material.clim[0]
         graphic._material.clim = (vmin, value)
@@ -200,6 +203,7 @@ def __init__(self, value: str):
     def value(self) -> str:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str):
         new_colors = make_colors(256, value)
         graphic._material.map.texture.data[:] = new_colors
@@ -226,6 +230,7 @@ def _validate(self, value):
     def value(self) -> str:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str):
         self._validate(value)
 
@@ -254,6 +259,7 @@ def _validate(self, value):
     def value(self) -> str:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str):
         self._validate(value)
 

@@ -1,4 +1,4 @@
-from typing import Any, List
+from typing import Any
 
 import numpy as np
 import pygfx
@@ -11,6 +11,7 @@
     BufferManager,
     FeatureEvent,
     to_gpu_supported_dtype,
+    block_reentrance,
 )
 from .utils import parse_colors
 
@@ -58,6 +59,7 @@ def __init__(
 
         super().__init__(data=data, isolated_buffer=isolated_buffer)
 
+    @block_reentrance
     def __setitem__(
         self,
         key: int | slice | np.ndarray[int | bool] | tuple[slice, ...],
@@ -155,6 +157,7 @@ def __init__(
     def value(self) -> pygfx.Color:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str | np.ndarray | tuple | list | pygfx.Color):
         value = pygfx.Color(value)
         graphic.world_object.material.color = value
@@ -174,6 +177,7 @@ def __init__(self, value: int | float):
     def value(self) -> float:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: float | int):
         graphic.world_object.material.size = float(value)
         self._value = value
@@ -192,6 +196,7 @@ def __init__(self, value: str):
     def value(self) -> str:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: str):
         if "Line" in graphic.world_object.material.__class__.__name__:
             graphic.world_object.material.thickness_space = value
@@ -243,6 +248,7 @@ def _fix_data(self, data):
 
         return to_gpu_supported_dtype(data)
 
+    @block_reentrance
     def __setitem__(
         self,
         key: int | slice | np.ndarray[int | bool] | tuple[slice, ...],
@@ -318,6 +324,7 @@ def _fix_sizes(
 
         return sizes
 
+    @block_reentrance
     def __setitem__(
         self,
         key: int | slice | np.ndarray[int | bool] | list[int | bool],
@@ -344,6 +351,7 @@ def __init__(self, value: float):
     def value(self) -> float:
         return self._value
 
+    @block_reentrance
     def set_value(self, graphic, value: float):
         graphic.world_object.material.thickness = value
         self._value = value
@@ -392,6 +400,7 @@ def __init__(
             # set vertex colors from cmap
             self._vertex_colors[:] = colors
 
+    @block_reentrance
     def __setitem__(self, key: slice, cmap_name):
         if not isinstance(key, slice):
             raise TypeError(

@@ -1,9 +1,9 @@
-from typing import Sequence, Tuple
+from typing import Sequence
 
 import numpy as np
 
 from ...utils import mesh_masks
-from ._base import GraphicFeature, FeatureEvent
+from ._base import GraphicFeature, FeatureEvent, block_reentrance
 
 
 class LinearSelectionFeature(GraphicFeature):
@@ -54,6 +54,7 @@ def value(self) -> np.float32:
         """
         return self._value
 
+    @block_reentrance
     def set_value(self, selector, value: float):
         # clip value between limits
         value = np.clip(value, self._limits[0], self._limits[1], dtype=np.float32)
@@ -117,6 +118,7 @@ def axis(self) -> str:
         """one of "x" | "y" """
         return self._axis
 
+    @block_reentrance
     def set_value(self, selector, value: Sequence[float]):
         """
         Set start, stop range of selector
@@ -231,6 +233,7 @@ def value(self) -> np.ndarray[float]:
         """
         return self._value
 
+    @block_reentrance
     def set_value(self, selector, value: Sequence[float]):
         """
         Set the selection of the rectangle selector.