55 lines
1.9 KiB
Python
55 lines
1.9 KiB
Python
import math
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from PyQt6.QtWidgets import QScrollBar
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from PyQt6.QtCore import pyqtSignal
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import logging
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log = logging.getLogger("scaledScrollBar")
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class ScaledScrollBar(QScrollBar):
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is_huge = False
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valueChanged = pyqtSignal(str)
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"""Signal emitted when the scroll bar value changes.
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**Note**: The value is a string and must be parsed into an int.
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QT's signal api only supports 32bit integers. Ints larger
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than 2**32-1 will overflow. Probably because there is some C/C++
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code involved. We work around this by converting the python int
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into a string."""
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def __init__(self):
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super(ScaledScrollBar, self).__init__()
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self.real_maximum = self.maximum()
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super().valueChanged.connect(self._valueChanged)
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def setValue(self, value: int) -> None:
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if self.is_huge:
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real_position = value / self.real_maximum
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super().setValue(round(self.maximum() * real_position))
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else:
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super().setValue(value)
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def setMaximum(self, maximum: int) -> None:
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if maximum > 2 ** 31:
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new_maximum = 1000 * math.log2(maximum)
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super().setMaximum(math.ceil(new_maximum))
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self.real_maximum = maximum
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if not self.is_huge:
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old_position = self.value() / self.maximum()
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self.setValue(round(new_maximum * old_position))
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self.is_huge = True
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else:
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self.is_huge = False
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super().setMaximum(maximum)
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def _valueChanged(self, value: int):
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if self.is_huge:
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real_value = (value / self.maximum()) * self.real_maximum
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# print("scaled value changed: %d -> %d (%f)" % (value, real_value, value / self.maximum()))
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self.valueChanged.emit(str(int(real_value)))
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else:
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self.valueChanged.emit(str(int(value)))
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