Source code for ccpn.ui.gui.widgets.ScrollBarVisibilityWatcher

"""
Module Documentation here
"""
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# Licence, Reference and Credits
#=========================================================================================
__copyright__ = "Copyright (C) CCPN project (http://www.ccpn.ac.uk) 2014 - 2020"
__credits__ = ("Ed Brooksbank, Luca Mureddu, Timothy J Ragan & Geerten W Vuister")
__licence__ = ("CCPN licence. See http://www.ccpn.ac.uk/v3-software/downloads/license")
__reference__ = ("Skinner, S.P., Fogh, R.H., Boucher, W., Ragan, T.J., Mureddu, L.G., & Vuister, G.W.",
                 "CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis",
                 "J.Biomol.Nmr (2016), 66, 111-124, http://doi.org/10.1007/s10858-016-0060-y")
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# Last code modification
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__modifiedBy__ = "$modifiedBy: Ed Brooksbank $"
__dateModified__ = "$dateModified: 2020-03-26 12:02:35 +0000 (Thu, March 26, 2020) $"
__version__ = "$Revision: 3.0.1 $"
#=========================================================================================
# Created
#=========================================================================================
__author__ = "$Author: Ed Brooksbank $"
__date__ = "$Date: 2020-03-26 11:44:06 +0000 (Thu, March 26, 2020) $"
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# Start of code
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from PyQt5 import QtWidgets
from PyQt5.QtCore import QObject
from PyQt5.QtGui import QShowEvent, QHideEvent
from ccpn.ui.gui.guiSettings import BORDERNOFOCUS_COLOUR


[docs]class ScrollBarVisibilityWatcher(QObject): """ Class to insert new widget into the corner of scroll areas """ def __init__(self, widget, cornerWidget=None): """ Initialise the widgets for the class """ super().__init__() # setup the corner widget if not cornerWidget: cornerWidget = QtWidgets.QWidget() # add a small widget with the top/left borders defined cornerWidget.setStyleSheet('border-top: 1px solid %s;' 'border-left: 1px solid %s;' 'background: transparent;' % (BORDERNOFOCUS_COLOUR, BORDERNOFOCUS_COLOUR)) self._cornerWidget = cornerWidget self._widget = widget # setup the event filters for the scroll bars horizontalScrollBar = self._getHorizontalScrollBar(widget) verticalScrollBar = self._getVerticalScrollBar(widget) horizontalScrollBar.installEventFilter(self) verticalScrollBar.installEventFilter(self) self.scrollBarChanged(horizontalScrollBar.isVisible(), verticalScrollBar.isVisible())
[docs] def eventFilter(self, watched, event): """Event filter to be attached to the scroll bars """ show = None if isinstance(event, QShowEvent): show = True elif isinstance(event, QHideEvent): show = False if show is not None: self._doScrollBarChange(show, watched) return super().eventFilter(watched, event)
def _doScrollBarChange(self, show, watched): """Update the scroll bar corner widget state """ horizontalScrollBar = self._getHorizontalScrollBar(self._widget) verticalScrollBar = self._getVerticalScrollBar(self._widget) if watched == horizontalScrollBar: horizontalVisible = show verticalVisible = verticalScrollBar is not None and verticalScrollBar.isVisible() elif watched == verticalScrollBar: horizontalVisible = horizontalScrollBar is not None and horizontalScrollBar.isVisible() verticalVisible = show else: raise Exception("scroll bar watcher received a object that wasn't watched %s" % repr(watched)) self.scrollBarChanged(horizontalVisible, verticalVisible) @staticmethod def _getHorizontalScrollBar(watched): return watched.horizontalScrollBar() @staticmethod def _getVerticalScrollBar(watched): return watched.verticalScrollBar()
[docs] def scrollBarChanged(self, horizontalVisible, verticalVisible): """Set the corner widget """ if horizontalVisible and verticalVisible: self._widget.setCornerWidget(self._cornerWidget) else: self._widget.setCornerWidget(None)