More minor fixes

examples/histogram.py

@@ -0,0 +1,82 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import numpy as np
+from qtpy.QtCore import QTimer
+from qtpy.QtWidgets import (
+    QApplication,
+    QPushButton,
+    QVBoxLayout,
+    QWidget,
+)
+
+from ndv.histogram._model import StatsModel
+from ndv.histogram._vispy import VispyHistogramView
+
+if TYPE_CHECKING:
+    from typing import Any
+
+
+class Controller:
+    """A (Qt) wrapper around another HistogramView with some additional controls."""
+
+    def __init__(self) -> None:
+        self._wdg = QWidget()
+        self._model = StatsModel()
+        self._view = VispyHistogramView()
+
+        # A HistogramView is both a StatsView and a LUTView
+        # StatModel <-> StatsView
+        self._model.events.histogram.connect(
+            lambda data: self._view.set_histogram(*data)
+        )
+        # LutModel <-> LutView (TODO)
+        # LutView -> LutModel (TODO: Currently LutView <-> LutView)
+        self._view.gammaChanged.connect(self._view.set_gamma)
+        self._view.climsChanged.connect(self._view.set_clims)
+
+        # Vertical box
+        self._vert = QPushButton("Vertical")
+        self._vert.setCheckable(True)
+        self._vert.toggled.connect(self._view.set_vertical)
+
+        # Log box
+        self._log = QPushButton("Logarithmic")
+        self._log.setCheckable(True)
+        self._log.toggled.connect(self._view.enable_range_log)
+
+        # Data updates
+        self._data_btn = QPushButton("Change Data")
+        self._data_btn.setCheckable(True)
+        self._data_btn.toggled.connect(
+            lambda toggle: self.timer.blockSignals(not toggle)
+        )
+
+        def _update_data() -> None:
+            """Replaces the displayed data."""
+            self._model.data = np.random.normal(10, 10, 10000)
+
+        self.timer = QTimer()
+        self.timer.setInterval(10)
+        self.timer.blockSignals(True)
+        self.timer.timeout.connect(_update_data)
+        self.timer.start()
+
+        # Layout
+        self._layout = QVBoxLayout(self._wdg)
+        self._layout.addWidget(self._view.view())
+        self._layout.addWidget(self._vert)
+        self._layout.addWidget(self._log)
+        self._layout.addWidget(self._data_btn)
+
+    def view(self) -> Any:
+        """Returns an object that can be displayed by the active backend."""
+        return self._wdg
+
+
+app = QApplication([])
+
+widget = Controller()
+widget.view().show()
+app.exec()

src/ndv/histogram/_model.py

@@ -16,12 +16,13 @@ class StatsModel:
     standard_deviation: float | None = None
     average: float | None = None
     histogram: tuple[np.ndarray, np.ndarray] | None = None
+    bins: int = 256
     bin_edges: np.ndarray | None = None
     _data: np.ndarray | None = None
 
     @property
     def data(self) -> np.ndarray:
-        if self._data is None:
+        if self._data is not None:
             return self._data
         raise Exception("Data has not yet been set!")
 
@@ -30,6 +31,6 @@ def data(self, data: np.ndarray) -> None:
         if data is None:
             return
         self._data = data
-        self.histogram = np.histogram(self._data)
+        self.histogram = np.histogram(self._data, bins=self.bins)
         self.average = np.average(self._data)
         self.standard_deviation = np.std(self._data)