Source code for gsdview.mousemanager
# -*- coding: utf-8 -*-
### Copyright (C) 2008-2012 Antonio Valentino <a_valentino@users.sf.net>
### This file is part of GSDView.
### GSDView is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
### GSDView is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
### GNU General Public License for more details.
### You should have received a copy of the GNU General Public License
### along with GSDView; if not, write to the Free Software
### Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
'''Mouse manager for the Qt4 graphics framework.
Mouse management for the Qt4 graphics framework is implemented by a set
of MouseMode objects, that provide specific event handlers and behave
like a descriptor, and a manager object that catches mouse events and
dispatch them to the appropriate hendler.
The MouseManager provides methods for eddeing/removing mouse modes,
making the system expandible, and also methods to register objects
(QGraphicsScene and QGraphicsView) to be controlled.
'''
from qt import QtCore, QtGui
from . import qt4support
__author__ = 'Antonio Valentino <a_valentino@users.sf.net>'
__date__ = '$Date$'
__revision__ = '$Revision$'
[docs]class MouseMode(QtCore.QObject):
'''Base class for mouse mode desctiptors.
Qt Graphics Framework mouse mode descriptors define some basic
property for mouse related matters:
- cursor
- dragmode
- eventFilter
- name
- label
- icon
The first three properties (not to be intender as python progremming
language property) are strongly characterizing of the way the mouse
works.
In particular the eventFilter method is used to filter all events
coming from graphics scenes an graphics views.
.. note:: in order to work properly the eventFilter should be installed
on both graphics scene and view and also on the scrollbars of
the graphics view.
So please always use the register method of MouseManager for
a proper installaton of al event filters.
'''
dragmode = QtGui.QGraphicsView.NoDrag
cursor = None
icon = QtGui.QIcon()
label = ''
name = ''
[docs] def eventFilter(self, obj, event):
'''Basic implementation of the eventFilter method.
The dafault implementation makes some basic operation such setting
the mouse cursor anc dispatch the event to specific methods:
- sceneEventFilter
- viewEventFilter
- scrollbarEventFilter
In most of the cases derived classes only need to specialize one or
more of this specific methods.
'''
if isinstance(obj, QtGui.QGraphicsScene):
return self.sceneEventFilter(obj, event)
elif isinstance(obj, QtGui.QGraphicsView):
if event.type() == QtCore.QEvent.Enter:
obj.setDragMode(self.dragmode)
if self.cursor:
obj.setCursor(self.cursor)
else:
obj.unsetCursor()
return self.viewEventFilter(obj, event)
elif isinstance(obj, QtGui.QScrollBar):
return self.scrollbarEventFilter(obj, event)
else:
return False
[docs]class PointerMode(MouseMode):
dragmode = QtGui.QGraphicsView.NoDrag
cursor = None
icon = qt4support.geticon('arrow.svg', __name__)
label = 'Pointer'
name = 'pointer'
[docs]class ScrollHandMode(MouseMode):
dragmode = QtGui.QGraphicsView.ScrollHandDrag
cursor = None
icon = qt4support.geticon('hand.svg', __name__)
label = 'Scroll hand'
name = 'hand'
[docs] def viewEventFilter(self, obj, event):
if event.type() == QtCore.QEvent.Wheel:
# Delta is expressed in 1/8 degree
delta = event.delta() / 8. # degree
# Conversion from degrees to zoom factor
if abs(delta) < 15:
# fine resolution mouse
k = 1.1 / abs(delta)
else:
# a factor of 1.1 every 15 degrees
k = 1.1 / 15.
if delta >= 0:
factor = k * delta
else:
factor = -1 / (k * delta)
obj.scale(factor, factor)
event.accept()
return True
else:
event.ignore()
return False
[docs] def scrollbarEventFilter(self, obj, event):
# ignore wheel events
if event.type() == QtCore.QEvent.Wheel:
return True
else:
return False
[docs]class RubberBandMode(MouseMode):
'''Mouse mode for rubber band selection.
:SIGNALS:
* :attr:`rubberBandSeclection`
'''
dragmode = QtGui.QGraphicsView.RubberBandDrag
cursor = QtCore.Qt.CrossCursor
icon = qt4support.geticon('area.svg', __name__)
label = 'Rubber band'
name = 'rubberband'
#: SIGNAL: it is emitted when a rectangular area is selected
#:
#: :C++ signature: `void rubberBandSeclection(const QRectF&)`
rubberBandSeclection = QtCore.Signal(QtCore.QRectF)
[docs] def sceneEventFilter(self, obj, event):
if event.type() == QtCore.QEvent.GraphicsSceneMouseRelease:
p0 = event.buttonDownScenePos(QtCore.Qt.LeftButton)
p1 = event.scenePos()
rect = QtCore.QRectF(p0, p1).normalized()
self.rubberBandSeclection.emit(rect)
return True
#return obj.eventFilter(obj, event) # @TODO: check
#return QtGui.QGraphicsScene.eventFilter(self, obj, event)
return False
[docs] def scrollbarEventFilter(self, obj, event):
# ignore wheel events if some button is pressed
if ((event.type() == QtCore.QEvent.Wheel)
and (event.buttons() != QtCore.Qt.NoButton)):
return True
else:
return False
[docs]class MouseManager(QtCore.QObject):
#: SIGNAL: it is emitted when the mouse mode is changed
#:
#: :C++ signature: `void modeChanged(const QString&)`
modeChanged = QtCore.Signal(str)
def __init__(self, parent=None, stdmodes=True, **kwargs):
QtCore.QObject.__init__(self, parent, **kwargs)
self._moderegistry = []
self.actions = QtGui.QActionGroup(self)
self.actions.setExclusive(True)
if stdmodes:
self.registerStandardModes()
[docs] def registerStandardModes(self):
for mode in (PointerMode, ScrollHandMode): # , RubberBandMode):
self.addMode(mode)
if len(self._moderegistry) and not self.actions.checkedAction():
self.actions.actions()[0].setChecked(True)
def _newModeAction(self, mode, parent):
if isinstance(mode.icon, basestring):
icon = QtGui.QIcon(mode.icon)
elif isinstance(mode.icon, QtGui.QStyle.StandardPixmap):
style = QtGui.QApplication.style()
icon = style.standardIcon(mode.icon)
else:
icon = mode.icon
action = QtGui.QAction(icon, self.tr(mode.label), parent,
statusTip=self.tr(mode.label),
checkable=True)
action.triggered.connect(lambda: self.modeChanged.emit(self.mode))
return action
def _getMode(self):
action = self.actions.checkedAction()
index = self.actions.actions().index(action)
return self._moderegistry[index].name
def _setMode(self, name):
names = self.modes()
index = names.index(name)
action = self.actions.actions()[index]
action.setChecked(True)
def _delMode(self, name):
names = [m.name for m in self._moderegistry]
index = names.index(name)
action = self.actions.actions()[index]
self.actions.removeAction(action)
del self._moderegistry[index]
#~ if actin.checked() and self._moderegistry:
#~ self.actions.actions()[0].setChecked(True)
mode = property(_getMode, _setMode, _delMode, 'mouse mode name')
[docs] def addMode(self, mode):
if isinstance(mode, type):
mode = mode(self)
action = self._newModeAction(mode, self.actions)
self.actions.addAction(action)
self._moderegistry.append(mode)
[docs] def getModeDescriptor(self, name=None):
'''Return the mouse mode object'''
try:
if name is None:
action = self.actions.checkedAction()
index = self.actions.actions().index(action)
else:
names = self.modes()
index = names.index(name)
return self._moderegistry[index]
except IndexError:
# @TODO: check
#raise ValueError('invalid mde nema: "%s"' % mode)
return None
[docs] def eventFilter(self, obj, event):
'''Events dispatcher'''
return self.getModeDescriptor().eventFilter(obj, event)
[docs] def register(self, obj):
'''Register a Qt graphics object to be monitored by the mouse manager.
QGraphicsScene and QGrapgicsViews (and descending classes) objects
can be registered to be monitored by the mouse manager.
Scene objects associated to views (passes as argument) are
automatically registered.
'''
obj.installEventFilter(self)
try:
obj.verticalScrollBar().installEventFilter(self)
except AttributeError:
# it is a QGraphicsScene
scene = obj
else:
scene = obj.scene()
# Avoid event filter duplication
scene.removeEventFilter(self)
scene.installEventFilter(self)
[docs] def unregister(self, obj):
'''Unregister monitored objects.
If the object passed as argument is not a registered object
nothing happens.
.. note:: this method never tries to unregister scene objects
associated to the view passed as argument.
'''
obj.removeEventFilter(self)
