Pyqt QGraphicView鼠标坐标系答案

【问题标题】：Pyqt QGraphicView mouse coordinate systemPyqt QGraphicView鼠标坐标系
【发布时间】：2017-08-05 05:06:19
【问题描述】：

我正在尝试使用 Qgraphicview 裁剪图像但我面临一个抵消问题这是QMainWindow

class ImageViewer(QtWidgets.QMainWindow):
    def __init__(self):
        super(ImageViewer, self).__init__()

        self.scene = QtWidgets.QGraphicsScene()
        self.imageLabel = QtWidgets.QLabel()
        self.cropLabel = QtWidgets.QLabel()
        self.scrollArea = QtWidgets.QScrollArea()
        self.scrollArea.setWidget(self.imageLabel)
        self.setCentralWidget(widget)

        self.scene.addWidget(splitter)
        self.view = QtWidgets.QGraphicsView(self.scene)
        self.view.setMouseTracking(True)
        self.view.setDragMode(QtWidgets.QGraphicsView.RubberBandDrag)

...

def mousePressEvent(self, eventQMouseEvent):
    print("pressed")
    self.originQPoint = self.view.mapToScene(eventQMouseEvent.pos())
    self.currentQRubberBand = QtWidgets.QRubberBand(QtWidgets.QRubberBand.Rectangle, self)
    self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, QtCore.QSize()))
    self.currentQRubberBand.show()

def mouseMoveEvent(self, eventQMouseEvent):
    self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, eventQMouseEvent.pos()).normalized())

def mouseReleaseEvent (self, eventQMouseEvent):
    #self.currentQRubberBand.hide()
    currentQRect = self.currentQRubberBand.geometry()
    print(currentQRect)
    self.currentQRubberBand.deleteLater()
    cropPixmap = self.pixmap.copy(currentQRect)
    self.cropLabel.setPixmap(cropPixmap)
    cropPixmap.save('output.png')

代码运行良好，但我有一个偏移量（似乎是边距或菜单栏值或混合）。所以我想我不是在好的系统中，但不知道如何访问它

【问题讨论】：

标签： python pyqt

【解决方案1】：

最后我离开了 QGraphicView 并在处理 QLabel 的专用 Widget 类中重新实现了鼠标事件。我工作得很好

class View(QtWidgets.QLabel):
def __init__(self):
    super(View,self).__init__()

    self.cropLabel = QtWidgets.QLabel(self)
    self.label = QtWidgets.QLabel(self)

    self.ogpixmap = QtGui.QPixmap()
    fileName = r'C:/Users/user11.HPO-SAMAT/Pictures/Lake.jpg'
    image = QtGui.QImage(fileName)
    self.pixmap = QtGui.QPixmap.fromImage(image)
    self.label.setPixmap(self.pixmap)
    self.label.adjustSize()

def mousePressEvent(self, event):
    self.originQPoint = event.pos()
    self.currentQRubberBand = QtWidgets.QRubberBand(QtWidgets.QRubberBand.Rectangle, self)
    self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, QtCore.QSize()))
    self.currentQRubberBand.show()

def mouseMoveEvent(self, event):
    self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, event.pos()).normalized())

def mouseReleaseEvent (self, event):
    self.currentQRubberBand.hide()
    currentQRect = self.currentQRubberBand.geometry()
    self.currentQRubberBand.deleteLater()
    cropPixmap = self.pixmap.copy(currentQRect)
    self.cropLabel.setPixmap(cropPixmap)

class Viewer(QtWidgets.QMainWindow):
def __init__(self):
    super().__init__()

    self.view = View()
    self.setCentralWidget(self.view)

【讨论】：