python - 在鼠标事件类之外读取或传递数据

Question

我有一个小部件，它使用橡皮筋来选择图像上的区域，它可以在任何方面进行编辑。我需要添加功能，一旦放置橡皮筋，它就可以再次调整大小或可编辑，所以我的想法是在鼠标释放事件后保存区域点(x，y，w，h)。

但现在的问题是如何将鼠标释放事件中读取的数据传递到橡皮筋类之外。

这是我的橡皮筋拖动和编辑代码。

class rubberBandWidget(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.rubberBand = QRubberBand(QRubberBand.Rectangle, self)
        self.tweaking = False
        self.tweakingpart = ""

    def mousePressEvent(self, event):
        pt = self.mapFromGlobal(event.globalPos())
        rg = self.rubberBand.geometry()

        if rg.isValid():
            tl, tr, bl, br = rg.topLeft(), rg.topRight(), rg.bottomLeft(), rg.bottomRight()
            off, offx, offy = QPoint(3, 3), QPoint(4, -3), QPoint(-3, 4)

            if QRect(tl - off, tl + off).contains(pt):
                self.tweakingpart = "topLeft";
                self.setCursor(Qt.SizeFDiagCursor)
            elif QRect(tr - off, tr + off).contains(pt):
                self.tweakingpart = "topRight";
                self.setCursor(Qt.SizeBDiagCursor)
            elif QRect(bl - off, bl + off).contains(pt):
                self.tweakingpart = "bottomLeft";
                self.setCursor(Qt.SizeBDiagCursor)
            elif QRect(br - off, br + off).contains(pt):
                self.tweakingpart = "bottomRight";
                self.setCursor(Qt.SizeFDiagCursor)
            elif QRect(tl + offx, tr - offx).contains(pt):
                self.tweakingpart = "top";
                self.setCursor(Qt.SizeVerCursor)
            elif QRect(bl + offx, br - offx).contains(pt):
                self.tweakingpart = "bottom"
                self.setCursor(Qt.SizeVerCursor)
            elif QRect(tl + offy, bl - offy).contains(pt):
                self.tweakingpart = "left";
                self.setCursor(Qt.SizeHorCursor)
            elif QRect(tr + offy, br - offy).contains(pt):
                self.tweakingpart = "right";
                self.setCursor(Qt.SizeHorCursor)

            if self.tweakingpart != "":
                self.tweaking = True
                return

        self.origin = pt
        self.rubberBand.setGeometry(QRect(self.origin, QtCore.QSize()))
        self.rubberBand.show()

    def mouseMoveEvent(self, event):
        pt = self.mapFromGlobal(event.globalPos())
        if self.tweaking:
            rg = self.rubberBand.geometry()
            if self.tweakingpart == "topLeft":
                rg.setTopLeft(pt)
            elif self.tweakingpart == "topRight":
                rg.setTopRight(pt)
            elif self.tweakingpart == "bottomLeft":
                rg.setBottomLeft(pt)
            elif self.tweakingpart == "bottomRight":
                rg.setBottomRight(pt)
            elif self.tweakingpart == "top":
                rg.setTop(pt.y())
            elif self.tweakingpart == "bottom":
                rg.setBottom(pt.y())
            elif self.tweakingpart == "left":
                rg.setLeft(pt.x())
            elif self.tweakingpart == "right":
                rg.setRight(pt.x())
            self.rubberBand.setGeometry(rg)
        else:
            self.rubberBand.setGeometry(QRect(self.origin, pt).normalized())

这是我关于发布事件的代码以及需要在类外部传递或读取的 (x, y, w, h) 数据。

def mouseReleaseEvent(self, event):
    self.tweaking = False
    self.tweakingpart = ""
    self.unsetCursor()

    if self.rubberBand.width() != 0 and self.rubberBand.height() != 0:
        print(self.rubberBand.x(), self.rubberBand.y(), self.rubberBand.width(), self.rubberBand.height())

我需要每次鼠标释放时的数据并保存它。因此，一旦用户需要再次调整大小和编辑，我的想法是设置橡皮筋的几何形状并重新运行该类，以便它可以再次编辑。

Answer 1

如果您想在类外部公开数据，您应该使用信号，如下所示:

import sys

from PyQt4 import QtCore, QtGui

class rubberBandWidget(QtGui.QWidget):
    rectChanged = QtCore.pyqtSignal(QtCore.QRect) # create signal
    ...
    def mouseReleaseEvent(self, event):
        self.tweaking = False
        self.tweakingpart = ""
        self.unsetCursor()

        if not self.rubberBand.geometry().isNull():
            self.rectChanged.emit(self.rubberBand.geometry()) # emit signal


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    w = rubberBandWidget()
    def on_rectChanged(rect):
        # receiver
        print(rect.x(), rect.y(), rect.width(), rect.height())
    w.rectChanged.connect(on_rectChanged) # connect signal
    w.show()
    sys.exit(app.exec_())

<小时/>

另一方面，我发现您的代码非常耦合，因为如果您想在另一个小部件中使用相同的功能，您将不得不复制所有代码，这是不可取的，所以我花时间创建一个自定义QRubberband 具有该功能，在下一部分中我将展示一个示例。

import sys

from PyQt4 import QtCore, QtGui


class RubberBand(QtGui.QRubberBand):
    rectChanged = QtCore.pyqtSignal(QtCore.QRect)

    TopLeft, TopRight, BottomLeft, BottomRight, Top, Bottom, Left, Right, NonePos = range(9)

    def __init__(self, parent=None):
        super(RubberBand, self).__init__(QtGui.QRubberBand.Rectangle, parent)
        self._widget = None
        self.setWidget(parent)
        self.tweakingpart = RubberBand.NonePos

        self.cursors = [QtCore.Qt.SizeFDiagCursor,
                        QtCore.Qt.SizeBDiagCursor,
                        QtCore.Qt.SizeBDiagCursor,
                        QtCore.Qt.SizeFDiagCursor,
                        QtCore.Qt.SizeVerCursor,
                        QtCore.Qt.SizeVerCursor,
                        QtCore.Qt.SizeHorCursor,
                        QtCore.Qt.SizeHorCursor]

    def setWidget(self, widget):
        if widget is None:
            return
        if self._widget is not None:
            self._widget.removeEventFilter(self)
        self._widget = widget
        self._widget.installEventFilter(self)
        self.setParent(widget)

    def eventFilter(self, obj, event):
        if self._widget is obj:
            if event.type() == QtCore.QEvent.MouseButtonPress:
                self.handleMousePressEvent(event.pos())
                return True
            elif event.type() == QtCore.QEvent.MouseMove:
                self.handleMouseMoveEvent(event.pos())
                return True
            elif event.type() == QtCore.QEvent.MouseButtonRelease:
                self.handleMouseReleaseEvent(event.pos())
                return True
        return super(RubberBand, self).eventFilter(obj, event)

    def handleMousePressEvent(self, pt):
        rg = self.geometry()
        if not rg.isValid():
            return
        off, offx, offy = QtCore.QPoint(3, 3), QtCore.QPoint(4, -3), QtCore.QPoint(-3, 4)
        rect = QtCore.QRect(-off, off)
        tl, tr, bl, br = rg.topLeft(), rg.topRight(), rg.bottomLeft(), rg.bottomRight()
        for i, coord in enumerate([tl, tr, bl, br]):
            rect.moveCenter(coord)
            if rect.contains(pt):
                self.tweakingpart = i
        if QtCore.QRect(tl + offx, tr - offx).contains(pt):
            self.tweakingpart = RubberBand.Top
        elif QtCore.QRect(bl + offx, br - offx).contains(pt):
            self.tweakingpart = RubberBand.Bottom
        elif QtCore.QRect(tl + offy, bl - offy).contains(pt):
            self.tweakingpart = RubberBand.Left
        elif QtCore.QRect(tr + offy, br - offy).contains(pt):
                self.tweakingpart = RubberBand.Right

        if 0 <= self.tweakingpart < RubberBand.NonePos:
            self._widget.setCursor(self.cursors[self.tweakingpart])
            return
        self.setGeometry(QtCore.QRect(pt, QtCore.QSize()))
        self.show()

    def handleMouseMoveEvent(self, pt):
        rg = self.geometry()
        if 0 <= self.tweakingpart < RubberBand.NonePos:
            if self.tweakingpart == RubberBand.TopLeft:
                rg.setTopLeft(pt)
            elif self.tweakingpart == RubberBand.TopRight:
                rg.setTopRight(pt)
            elif self.tweakingpart == RubberBand.BottomLeft:
                rg.setBottomLeft(pt)
            elif self.tweakingpart == RubberBand.BottomRight:
                rg.setBottomRight(pt)
            elif self.tweakingpart == RubberBand.Top:
                rg.setTop(pt.y())
            elif self.tweakingpart == RubberBand.Bottom:
                rg.setBottom(pt.y())
            elif self.tweakingpart == RubberBand.Left:
                rg.setLeft(pt.x())
            elif self.tweakingpart == RubberBand.Right:
                rg.setRight(pt.x())
        else:
            rg = QtCore.QRect(rg.topLeft(), pt).normalized()
        self.setGeometry(rg)

    def handleMouseReleaseEvent(self, pt):
        self.tweakingpart = RubberBand.NonePos
        self._widget.unsetCursor()
        if not self.geometry().isNull():
            self.rectChanged.emit(self.geometry())


class TestWidget(QtGui.QWidget):
    pass


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    w = TestWidget()
    rubberBand = RubberBand(w)
    def on_rectChanged(rect):
        print(rect.x(), rect.y(), rect.width(), rect.height())
    rubberBand.rectChanged.connect(on_rectChanged)
    w.show()
    sys.exit(app.exec_())