我真的很喜欢这个想法，并试图将它概括为创建一个小部件，您可以将“主视图”传递给它，它会创建一个概览，您可以使用它来平移和放大。不幸的是，我还没有让它工作目前还没有时间研究它，但我想我会分享迄今为止的进展。
这是小部件代码：
"""
Overview widget
"""
from PyQt4 import QtGui, QtCore
class MovableGraphicsRectItem(QtGui.QGraphicsRectItem):
'''special GraphicsRectItem that is aware of its position and does
something if the position is changed'''
def __init__(self, callback=None):
super(MovableGraphicsRectItem, self).__init__()
self.setFlags(QtGui.QGraphicsItem.ItemIsMovable |
QtGui.QGraphicsItem.ItemSendsScenePositionChanges)
self.setCursor(QtCore.Qt.PointingHandCursor)
self.callback = callback
def itemChange(self, change, value):
if change == QtGui.QGraphicsItem.ItemPositionChange and self.callback:
self.callback(value)
return super(MovableGraphicsRectItem, self).itemChange(change, value)
def activate(self):
self.setFlags(QtGui.QGraphicsItem.ItemIsMovable |
QtGui.QGraphicsItem.ItemSendsScenePositionChanges)
self.setCursor(QtCore.Qt.PointingHandCursor)
def deactivate(self):
self.setFlag(QtGui.QGraphicsItem.ItemIsMovable, False)
self.setFlag(QtGui.QGraphicsItem.ItemSendsScenePositionChanges, False)
self.setCursor(QtCore.Qt.ArrowCursor)
class MouseInsideFilterObj(QtCore.QObject):
def __init__(self, enterCallback, leaveCallback):
QtCore.QObject.__init__(self)
self.enterCallback = enterCallback
self.leaveCallback = leaveCallback
def eventFilter(self, obj, event):
if event.type() == 10: # QtCore.QEvent.Type.Enter:
self.enterCallback(obj)
print('Enter event')
if event.type() == 11: # QtCore.QEvent.Type.Leave:
self.leaveCallback(obj)
print('Leave event')
return False
class Overview(QtGui.QGraphicsView):
'''provides a view that shows the entire scene and shows the area that
the main view is zoomed to. Alows user to move the view area around and
change the zoom level'''
def __init__(self, mainView):
QtGui.QGraphicsView.__init__(self)
self.setWindowTitle('Overview')
self.resize(QtCore.QSize(400, 300))
self._mainView = mainView
self.setScene(mainView.scene())
mouseFilter = MouseInsideFilterObj(self.enterGV, self.leaveGV)
self.viewport().installEventFilter(mouseFilter)
self._tracker = MovableGraphicsRectItem(
lambda pos: self._mainView.setSceneRect(
QtCore.QRectF(self._mainView.viewport().geometry())))
self._tracker.setRect(self._getMainViewArea_())
self._tracker.setPen(QtGui.QPen(QtCore.Qt.darkCyan))
self.scene().addItem(self._tracker)
def _getMainViewArea_(self):
mainView = self._mainView
visibleSceneRect = mainView.mapToScene(
mainView.viewport().geometry()).boundingRect()
return visibleSceneRect
def resizeEvent(self, event):
self.fitInView(self.sceneRect(), QtCore.Qt.KeepAspectRatio)
def leaveGV(self, gv):
if gv is self.overview:
print('exited overview')
self.tracker.deactivate()
def enterGV(self, gv):
if gv is self.overview:
print('using overview')
self.tracker.activate()
这里是测试脚本代码：
import sys
from PyQt4 import QtGui, QtCore
import overviewWidget as ov
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
# the scene with some rectangles
scene = QtGui.QGraphicsScene()
scene.addRect(30, 30, 100, 50, pen=QtGui.QPen(QtCore.Qt.darkGreen))
scene.addRect(150, 0, 30, 80, pen=QtGui.QPen(QtCore.Qt.darkYellow))
scene.addRect(80, 80, 100, 20, pen=QtGui.QPen(QtCore.Qt.darkMagenta))
scene.addRect(200, 10, 30, 80, pen=QtGui.QPen(QtCore.Qt.darkRed))
# the main view
mainView = QtGui.QGraphicsView(scene)
mainView.resize(600, 400)
mainView.update()
mainView.show()
# the overview
overview = ov.Overview(mainView)
overview.update()
overview.show()
sys.exit(app.exec_())