Source code for glue.utils.qt.widget_properties

"""
The classes in this module provide a property-like interface
to widget instance variables in a class. These properties translate
essential pieces of widget state into more convenient python objects
(for example, the check state of a button to a bool).

Example Use::

    class Foo(object):
        bar = ButtonProperty('_button')

        def __init__(self):
            self._button = QtWidgets.QCheckBox()

    f = Foo()
    f.bar = True  # equivalent to f._button.setChecked(True)
    assert f.bar == True
"""

import math
from functools import reduce

from glue.logger import logger
from glue.utils.array import pretty_number

from echo.qt.connect import _find_combo_data, UserDataWrapper

# Backward-compatibility
from echo.qt import (connect_checkable_button as connect_bool_button,  # noqa
                                   connect_combo_data as connect_current_combo,  # noqa
                                   connect_combo_text as connect_current_combo_text,  # noqa
                                   connect_float_text as connect_float_edit,  # noqa
                                   connect_value, connect_text)  # noqa

connect_int_spin = connect_value

__all__ = ['WidgetProperty', 'CurrentComboDataProperty',
           'CurrentComboTextProperty', 'CurrentTabProperty', 'TextProperty',
           'ButtonProperty', 'FloatLineProperty', 'ValueProperty']


[docs]class WidgetProperty(object): """ Base class for widget properties Subclasses implement, at a minimum, the "get" and "set" methods, which translate between widget states and python variables Parameters ---------- att : str The location, within a class instance, of the widget to wrap around. If the widget is nested inside another variable, normal '.' syntax can be used (e.g. 'sub_window.button') docstring : str, optional Optional short summary for the property. Used by sphinx. Should be 1 sentence or less. """ def __init__(self, att, docstring=''): self.__doc__ = docstring self._att = att.split('.') def __get__(self, instance, type=None): # Under certain circumstances, PyQt will try and access these properties # while loading the ui file, so we have to be robust to failures. # However, we print out a warning if things fail. try: widget = reduce(getattr, [instance] + self._att) return self.getter(widget) except Exception: logger.info("An error occured when accessing attribute {0} of {1}. Returning None.".format('.'.join(self._att), instance)) return None def __set__(self, instance, value): widget = reduce(getattr, [instance] + self._att) self.setter(widget, value)
[docs] def getter(self, widget): """ Return the state of a widget. Depends on type of widget, and must be overridden""" raise NotImplementedError() # pragma: no cover
[docs] def setter(self, widget, value): """ Set the state of a widget to a certain value""" raise NotImplementedError() # pragma: no cover
[docs]class CurrentComboDataProperty(WidgetProperty): """ Wrapper around the data in QComboBox. """
[docs] def getter(self, widget): """ Return the itemData stored in the currently-selected item """ if widget.currentIndex() == -1: return None else: data = widget.itemData(widget.currentIndex()) if isinstance(data, UserDataWrapper): return data.data else: return data
[docs] def setter(self, widget, value): """ Update the currently selected item to the one which stores value in its itemData """ # Note, we don't use findData here because it doesn't work # well with non-str data try: idx = _find_combo_data(widget, value) except ValueError: if value is None: idx = -1 else: raise ValueError("Cannot find data '{0}' in combo box".format(value)) widget.setCurrentIndex(idx)
CurrentComboProperty = CurrentComboDataProperty
[docs]class CurrentComboTextProperty(WidgetProperty): """ Wrapper around the text in QComboBox. """
[docs] def getter(self, widget): """ Return the itemData stored in the currently-selected item """ if widget.currentIndex() == -1: return None else: return widget.itemText(widget.currentIndex())
[docs] def setter(self, widget, value): """ Update the currently selected item to the one which stores value in its itemData """ idx = widget.findText(value) if idx == -1: if value is not None: raise ValueError("Cannot find text '{0}' in combo box".format(value)) widget.setCurrentIndex(idx)
[docs]class CurrentTabProperty(WidgetProperty): """ Wrapper around QTabWidget. """
[docs] def getter(self, widget): """ Return the itemData stored in the currently-selected item """ return widget.tabText(widget.currentIndex())
[docs] def setter(self, widget, value): """ Update the currently selected item to the one which stores value in its itemData """ for idx in range(widget.count()): if widget.tabText(idx) == value: break else: raise ValueError("Cannot find value '{0}' in tabs".format(value)) widget.setCurrentIndex(idx)
[docs]class TextProperty(WidgetProperty): """ Wrapper around the text() and setText() methods for QLabel etc """
[docs] def getter(self, widget): return widget.text()
[docs] def setter(self, widget, value): widget.setText(value) if hasattr(widget, 'editingFinished'): widget.editingFinished.emit()
[docs]class ButtonProperty(WidgetProperty): """ Wrapper around the check state for QAbstractButton widgets """
[docs] def getter(self, widget): return widget.isChecked()
[docs] def setter(self, widget, value): widget.setChecked(value)
[docs]class FloatLineProperty(WidgetProperty): """ Wrapper around the text state for QLineEdit widgets. Assumes that the text is a floating-point number """
[docs] def getter(self, widget): try: return float(widget.text()) except ValueError: return 0
[docs] def setter(self, widget, value): widget.setText(pretty_number(value)) widget.editingFinished.emit()
[docs]class ValueProperty(WidgetProperty): """ Wrapper around widgets with value() and setValue() Parameters ---------- att : str The location, within a class instance, of the widget to wrap around. If the widget is nested inside another variable, normal '.' syntax can be used (e.g. 'sub_window.button') docstring : str, optional Optional short summary for the property. Used by sphinx. Should be 1 sentence or less. value_range : tuple, optional If set, the slider values are mapped to this range. log : bool, optional If `True`, the mapping is assumed to be logarithmic instead of linear. """ def __init__(self, att, docstring='', value_range=None, log=False): super(ValueProperty, self).__init__(att, docstring=docstring) if log: if value_range is None: raise ValueError("log option can only be set if value_range is given") else: value_range = math.log10(value_range[0]), math.log10(value_range[1]) self.log = log self.value_range = value_range
[docs] def getter(self, widget): val = widget.value() if self.value_range is not None: imin, imax = widget.minimum(), widget.maximum() vmin, vmax = self.value_range val = (val - imin) / (imax - imin) * (vmax - vmin) + vmin if self.log: val = 10 ** val return val
[docs] def setter(self, widget, val): if self.log: val = math.log10(val) if self.value_range is not None: imin, imax = widget.minimum(), widget.maximum() vmin, vmax = self.value_range val = (val - vmin) / (vmax - vmin) * (imax - imin) + imin widget.setValue(int(val))