Python QGraphicsScene.setSelectionArea方法代码示例

# 需要导入模块: from PyQt5.QtWidgets import QGraphicsScene [as 别名]
# 或者: from PyQt5.QtWidgets.QGraphicsScene import setSelectionArea [as 别名]

#.........这里部分代码省略.........
        """ Returns the scene's current image pixmap as a QImage, or else None if no image exists.
        :rtype: QImage | None
        """
        if self.hasImage():
            return self._pixmapHandle.pixmap().toImage()
        return None

    def setImage(self, image):
        """ Set the scene's current image pixmap to the input QImage or QPixmap.
        Raises a RuntimeError if the input image has type other than QImage or QPixmap.
        :type image: QImage | QPixmap
        """
        if type(image) is QPixmap:
            pixmap = image
        elif type(image) is QImage:
            pixmap = QPixmap.fromImage(image)
        else:
            raise RuntimeError("ImageViewer.setImage: Argument must be a QImage or QPixmap.")
        if self.hasImage():
            self._pixmapHandle.setPixmap(pixmap)
        else:
            self._pixmapHandle = self.scene.addPixmap(pixmap)
        self.setSceneRect(QRectF(pixmap.rect()))  # Set scene size to image size.
        self.updateViewer()

    def loadImageFromFile(self, fileName=""):
        """ Load an image from file.
        Without any arguments, loadImageFromFile() will popup a file dialog to choose the image file.
        With a fileName argument, loadImageFromFile(fileName) will attempt to load the specified image file directly.
        """
        if len(fileName) == 0:
            if QT_VERSION_STR[0] == '4':
                fileName = QFileDialog.getOpenFileName(self, "Open image file.")
            elif QT_VERSION_STR[0] == '5':
                fileName, dummy = QFileDialog.getOpenFileName(self, "Open image file.")
        if len(fileName) and os.path.isfile(fileName):
            image = QImage(fileName)
            self.setImage(image)

    def updateViewer(self):
        """ Show current zoom (if showing entire image, apply current aspect ratio mode).
        """
        if not self.hasImage():
            return
        if len(self.zoomStack) and self.sceneRect().contains(self.zoomStack[-1]):
            self.fitInView(self.zoomStack[-1], Qt.IgnoreAspectRatio)  # Show zoomed rect (ignore aspect ratio).
        else:
            self.zoomStack = []  # Clear the zoom stack (in case we got here because of an invalid zoom).
            self.fitInView(self.sceneRect(), self.aspectRatioMode)  # Show entire image (use current aspect ratio mode).

    def resizeEvent(self, event):
        """ Maintain current zoom on resize.
        """
        self.updateViewer()

    def mousePressEvent(self, event):
        """ Start mouse pan or zoom mode.
        """
        scenePos = self.mapToScene(event.pos())
        if event.button() == Qt.LeftButton:
            if self.canPan:
                self.setDragMode(QGraphicsView.ScrollHandDrag)
            self.leftMouseButtonPressed.emit(scenePos.x(), scenePos.y())
        elif event.button() == Qt.RightButton:
            if self.canZoom:
                self.setDragMode(QGraphicsView.RubberBandDrag)
            self.rightMouseButtonPressed.emit(scenePos.x(), scenePos.y())
        QGraphicsView.mousePressEvent(self, event)

    def mouseReleaseEvent(self, event):
        """ Stop mouse pan or zoom mode (apply zoom if valid).
        """
        QGraphicsView.mouseReleaseEvent(self, event)
        scenePos = self.mapToScene(event.pos())
        if event.button() == Qt.LeftButton:
            self.setDragMode(QGraphicsView.NoDrag)
            self.leftMouseButtonReleased.emit(scenePos.x(), scenePos.y())
        elif event.button() == Qt.RightButton:
            if self.canZoom:
                viewBBox = self.zoomStack[-1] if len(self.zoomStack) else self.sceneRect()
                selectionBBox = self.scene.selectionArea().boundingRect().intersected(viewBBox)
                self.scene.setSelectionArea(QPainterPath())  # Clear current selection area.
                if selectionBBox.isValid() and (selectionBBox != viewBBox):
                    self.zoomStack.append(selectionBBox)
                    self.updateViewer()
            self.setDragMode(QGraphicsView.NoDrag)
            self.rightMouseButtonReleased.emit(scenePos.x(), scenePos.y())

    def mouseDoubleClickEvent(self, event):
        """ Show entire image.
        """
        scenePos = self.mapToScene(event.pos())
        if event.button() == Qt.LeftButton:
            self.leftMouseButtonDoubleClicked.emit(scenePos.x(), scenePos.y())
        elif event.button() == Qt.RightButton:
            if self.canZoom:
                self.zoomStack = []  # Clear zoom stack.
                self.updateViewer()
            self.rightMouseButtonDoubleClicked.emit(scenePos.x(), scenePos.y())
        QGraphicsView.mouseDoubleClickEvent(self, event)