[proof of concept] make labelled range sliders expandable by modifying label range

src/superqt/sliders/_labeled.py

@@ -150,7 +150,12 @@ def __init__(self, *args, **kwargs) -> None:
 
     def _setValue(self, value: float):
         """Convert the value from float to int before setting the slider value."""
-        self._slider.setValue(int(value))
+        value = int(value)
+        if self._slider.maximum() < value:
+            self._slider.setMaximum(value)
+        elif self._slider.minimum() > value:
+            self._slider.setMinimum(value)
+        self._slider.setValue(value)
 
     def _rename_signals(self):
         # for subclasses
@@ -209,6 +214,10 @@ def setEdgeLabelMode(self, opt: EdgeLabelMode) -> None:
 
         QApplication.processEvents()
 
+    def setLabelSpinBoxRange(self, min: int, max: int):
+        """Change valid label values independently of slider range."""
+        self._label.setRange(int(min), int(max))
+
 
 class QLabeledDoubleSlider(QLabeledSlider):
     _slider_class = QDoubleSlider
@@ -222,9 +231,17 @@ def __init__(self, *args, **kwargs) -> None:
         self.setDecimals(2)
 
     def _setValue(self, value: float):
-        """Convert the value from float to int before setting the slider value."""
+        """Override method in the subclass which converts float to int."""
+        if self._slider.maximum() < value:
+            self._slider.setMaximum(value)
+        elif self._slider.minimum() > value:
+            self._slider.setMinimum(value)
         self._slider.setValue(value)
 
+    def setLabelSpinBoxRange(self, min: float, max: float):
+        """Change valid label values independently of slider range."""
+        self._label.setRange(min, max)
+
     def _rename_signals(self):
         self.valueChanged = self._fvalueChanged
         self.sliderMoved = self._fsliderMoved
@@ -574,8 +591,8 @@ def setMode(self, opt: EdgeLabelMode):
             with contextlib.suppress(Exception):
                 self._slider.rangeChanged.disconnect(self.setRange)
         else:
-            self.setMinimum(self._slider.minimum())
-            self.setMaximum(self._slider.maximum())
+            self.setMinimum(min(self._slider.minimum(), self.minimum()))
+            self.setMaximum(max(self._slider.maximum(), self.maximum()))
             self._slider.rangeChanged.connect(self.setRange)
         self._update_size()
 

tests/test_sliders/test_labeled_slider.py

@@ -85,3 +85,43 @@ def test_editing_float(qtbot):
     slider._label.setValue(0.5)
     slider._label.editingFinished.emit()
     assert slider.value() == 0.5
+
+
+@pytest.mark.parametrize("cls", [QLabeledSlider, QLabeledDoubleSlider])
+def test_extended_label_spinbox_range(cls, qtbot):
+    slider = cls()
+    mock = Mock()
+    qtbot.addWidget(slider)
+    slider.setRange(0, 10)
+    slider.rangeChanged.connect(mock)
+    assert slider._label.minimum() == 0
+    assert slider._label.maximum() == 10
+    assert slider.minimum() == 0
+    assert slider.maximum() == 10
+
+    # changing slider value without changing spinbox range should return a clipped value
+    # slider._label.setValue(20)
+    # slider._label.editingFinished.emit()  # simulate editing the label manually
+    # qtbot.wait(20)
+    # assert slider.value() == 10
+    # assert slider.maximum() == 10
+
+    # after changing label range, setting the label to a value outside the range should
+    # update the slider min/max as appropriate
+    slider.setLabelSpinBoxRange(-10, 20)
+
+    with qtbot.waitSignal(slider.rangeChanged):
+        slider._label.setValue(15)
+        assert slider._label.minimum() == -10
+        slider._label.editingFinished.emit()  # simulate editing the label manually
+        assert slider._label.minimum() == -10
+    assert slider.value() == 15
+    assert slider.minimum() == 0  # unchanged
+    assert slider.maximum() == 15  # changed
+
+    with qtbot.waitSignal(slider.rangeChanged):
+        slider._label.setValue(-5)
+        slider._label.editingFinished.emit()  # simulate editing the label manually
+    assert slider.value() == -5
+    assert slider.minimum() == -5  # changed
+    assert slider.maximum() == 15  # unchanged