"""
Custom :class:`QtWidgets.QDoubleSpinBox` and :class:`QtWidgets.QSpinBox` classes.
In situations where the value of the spinbox is used to represent the position/value
of equipment in the laboratory one typically does not want to connect the
:meth:`~QtWidgets.QDoubleSpinBox.valueChanged` signal of the spinbox to change the
value of the equipment because each numeric key press would be sent to the equipment.
For example, if you wanted to set the position/value of the equipment to 1234 then
typing the value 1234 in the spinbox would send:
* 1 :math:`\\rightarrow` set the value of the equipment to be 1
* 12 :math:`\\rightarrow` set the value of the equipment to be 12
* 123 :math:`\\rightarrow` set the value of the equipment to be 123
* 1234 :math:`\\rightarrow` set the value of the equipment to be 1234
These custom :class:`QAbstractSpinBox` subclasses will emit the
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` signal when any of the
following events occur:
* the spinbox loses focus
* the Enter key is pressed
* the Up, Down, PageUp or PageDown keys are pressed
* the Increment and Decrement buttons are clicked
"""
from enum import Enum
from .. import QtGui
from .. import QtWidgets
from .. import binding
from ..convert import number_to_si
from ..convert import si_to_number
[docs]class SpinBox(QtWidgets.QSpinBox):
def __init__(self, *, parent=None, value=0, minimum=0, maximum=100, step=1,
unit='', tooltip='', value_changed=None, editing_finished=None):
"""A :class:`~QtWidgets.QSpinBox` that emits
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` after a
:meth:`~QtWidgets.QAbstractSpinBox.stepBy` signal.
Parameters
----------
parent : :class:`QtWidgets.QWidget`, optional
The parent widget.
value : :class:`int`, optional
The initial value.
minimum : :class:`int`, optional
The minimum value.
maximum : :class:`int`, optional
The maximum value.
step : :class:`int`, optional
The step-by size.
unit : :class:`str` or :class:`enum.Enum`, optional
The text to display after the value.
tooltip : :class:`str`, optional
The tooltip to use for the :class:`SpinBox`.
value_changed
A callable function to use as a slot for the
:meth:`~QtWidgets.QSpinBox.valueChanged` signal.
editing_finished
A callable function to use as a slot for the
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` signal.
"""
super(SpinBox, self).__init__(parent=parent)
self.setMinimum(minimum)
self.setMaximum(maximum)
self.setValue(value)
self.setSingleStep(step)
self.setToolTip(tooltip)
if isinstance(unit, Enum):
self.setSuffix(unit.value)
else:
self.setSuffix(unit)
if value_changed:
self.valueChanged.connect(value_changed) # noqa: QSpinBox.valueChanged
if editing_finished:
self.editingFinished.connect(editing_finished) # noqa: QSpinBox.editingFinished
def stepBy(self, steps):
"""Overrides :meth:`QtWidgets.QAbstractSpinBox.stepBy`.
Allows Increment/Decrement button clicks and Up/Down/PageUp/PageDown
key presses to update the value of the spinbox and then emit the
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` signal.
"""
super(SpinBox, self).stepBy(steps)
self.editingFinished.emit() # noqa: QSpinBox.editingFinished
[docs]class DoubleSpinBox(QtWidgets.QDoubleSpinBox):
def __init__(self, *, parent=None, value=0, minimum=0, maximum=100,
step=1, decimals=2, use_si_prefix=False, unit='', tooltip='',
value_changed=None, editing_finished=None):
"""A :class:`~QtWidgets.QDoubleSpinBox` that emits
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` after a
:meth:`~QtWidgets.QAbstractSpinBox.stepBy` signal.
Parameters
----------
parent : :class:`QtWidgets.QWidget`, optional
The parent widget.
value : :class:`float`, optional
The initial value.
minimum : :class:`float`, optional
The minimum value.
maximum : :class:`float`, optional
The maximum value.
step : :class:`float`, optional
The step-by size.
decimals : :class:`int`, optional
The number of digits after the decimal place to use to show the value.
use_si_prefix : :class:`bool`, optional
Whether to use an SI prefix to represent the number, e.g. a value of
1.2e-9 would be represented as '1.2 n'
unit : :class:`str` or :class:`enum.Enum`, optional
The text to display after the value.
tooltip : :class:`str`, optional
The tooltip to use for the :class:`DoubleSpinBox`.
value_changed
A callable function to use as a slot for the
:meth:`~QtWidgets.QDoubleSpinBox.valueChanged` signal.
editing_finished
A callable function to use as a slot for the
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` signal.
"""
super(DoubleSpinBox, self).__init__(parent=parent)
self._using_pyside = binding.name.startswith('PySide')
if use_si_prefix:
self._validator = _SIPrefixValidator()
si_prefix_limit = 0.99999999999999e27
if minimum < -si_prefix_limit:
minimum = -si_prefix_limit
if maximum > si_prefix_limit:
maximum = si_prefix_limit
else:
self._validator = None
self.setDecimals(decimals) # must come before setValue
self.setSingleStep(step)
self.setMinimum(minimum)
self.setMaximum(maximum)
self.setValue(value)
self.setToolTip(tooltip)
if isinstance(unit, Enum):
self.setSuffix(unit.value)
else:
self.setSuffix(unit)
if value_changed:
self.valueChanged.connect(value_changed) # noqa: QDoubleSpinBox.valueChanged
if editing_finished:
self.editingFinished.connect(editing_finished) # noqa: QDoubleSpinBox.editingFinished
[docs] def validate(self, text, position):
"""Overrides :meth:`QtWidgets.QAbstractSpinBox.validate`."""
if self._validator is None:
return super(DoubleSpinBox, self).validate(text, position)
# Don't pass self.cleanText() to the validator because it does not always return
# what is expected. For example, if `text`='0.12f3' then self.cleanText() returns
# '0.12f' (which has removed the 3 at the end) and this causes the validator to
# return Acceptable and the displayed text in the DoubleSpinBox then becomes
# '0.12f3' which is Invalid and one can no longer edit the value in the
# DoubleSpinBox. It is okay to use self.cleanText() in the methods self.fixup(),
# self.valueFromText() and self.stepBy()
text = text.rstrip(self.suffix()).lstrip(self.prefix())
state = self._validator.validate(text, position - len(self.prefix()))
if self._using_pyside:
return state
# PyQt expects Tuple[QValidator.State, str, int] to be returned
return state, text, position
[docs] def fixup(self, text):
"""Overrides :meth:`QtWidgets.QAbstractSpinBox.fixup`."""
if self._validator is None:
return super(DoubleSpinBox, self).fixup(text)
return self._validator.fixup(self.cleanText())
[docs] def valueFromText(self, text):
"""Overrides :meth:`QtWidgets.QDoubleSpinBox.valueFromText`."""
if self._validator is None:
return super(DoubleSpinBox, self).valueFromText(text)
return si_to_number(self.cleanText())
[docs] def textFromValue(self, value):
"""Overrides :meth:`QtWidgets.QDoubleSpinBox.textFromValue`."""
if self._validator is None:
return super(DoubleSpinBox, self).textFromValue(value)
val, si_prefix = number_to_si(value)
return f'{val:.{self.decimals()}f} {si_prefix}'
[docs] def setValue(self, value):
"""Overrides :meth:`QtWidgets.QDoubleSpinBox.setValue`."""
if self._validator is None:
super(DoubleSpinBox, self).setValue(value)
else:
coerced = max(min(si_to_number(str(value)), self.maximum()), self.minimum())
self.lineEdit().setText(self.textFromValue(coerced))
def stepBy(self, steps):
"""Overrides :meth:`QtWidgets.QAbstractSpinBox.stepBy`.
Allows Increment/Decrement button clicks and Up/Down/PageUp/PageDown
key presses to update the value of the spinbox and then emit the
:meth:`~QtWidgets.QAbstractSpinBox.editingFinished` signal.
If an SI prefix is enabled then uses a step size that is rescaled
for the current value.
"""
if self._validator is None:
super(DoubleSpinBox, self).stepBy(steps)
else:
number = si_to_number(self.cleanText())
coerced = max(min(number, self.maximum()), self.minimum())
_, si_prefix = number_to_si(coerced)
value = number + si_to_number(str(steps * self.singleStep()) + si_prefix)
self.setValue(value)
self.editingFinished.emit() # noqa: QDoubleSpinBox.editingFinished
class _SIPrefixValidator(QtGui.QValidator):
"""Validate text that may or may not contain an SI prefix for the :class:`DoubleSpinBox`."""
def validate(self, string, position):
"""Overrides :meth:`QtGui.QValidator.validate`."""
if not string:
return self.State.Intermediate
if len(string) == 1:
if string.isdigit():
return self.State.Acceptable
if string in '+-.':
return self.State.Intermediate
return self.State.Invalid
try:
si_to_number(string)
except ValueError:
pass
else:
return self.State.Acceptable
string_lower = string.lower()
# can only have one '.' and it must be before an 'e'
if string[position-1] == '.':
if (string.count('.') == 1) and ('e' not in string_lower[:position-1]):
return self.State.Intermediate
return self.State.Invalid
# can only have one 'e' and everything before it must be in 0123456789 or +-.
if string_lower[position-1] == 'e':
if string_lower.count('e') == 1 and all(c.isdigit() or c in '+-.' for c in string_lower[:position-1]):
return self.State.Intermediate
return self.State.Invalid
# a '+' or '-' symbol can only follow an 'e'
if string[position-1] in '+-':
if string_lower[position-2] == 'e':
return self.State.Intermediate
return self.State.Invalid
return self.State.Invalid
def fixup(self, text):
"""Overrides :meth:`QtGui.QValidator.fixup`."""
try:
number, si = number_to_si(si_to_number(text))
return f'{number} {si}'
except ValueError:
return ''