Question

我要在窗口中插入一些大图像，并定义窗口大小。如果我的图像大小大于窗口，则必须有滚动条。我还实现了平移和缩放功能，以便我可以将图像调整为任何大小。感谢此示例代码的antiearth

from PyQt4 import QtCore, QtGui
import sys

class Annotator(QtGui.QWidget):
def __init__(self):
    QtGui.QWidget.__init__(self)

    self.image = None
    self.scale = 1.0
    self.position = (100, 100)

    self.pressed = None
    self.anchor = None

    self.load('Some LArge Image/Images.png') 

def load(self, filename):
    self.image = QtGui.QImage(filename)

def mousePressEvent(self, event):
    print 'PRESSED : ',event.pos()
    self.pressed = event.pos()
    self.anchor = self.position

def mouseReleaseEvent(self, event):
    self.pressed = None

def mouseMoveEvent(self, event):
    if (self.pressed):
        dx, dy = event.x() - self.pressed.x(), event.y() - self.pressed.y()
        self.position = (self.anchor[0] - dx, self.anchor[1] - dy)
    self.repaint()


def wheelEvent(self, event):
    oldscale = self.scale
    self.scale += event.delta() / 1200.0
    if (self.scale < 0.1):
        self.scale = oldscale

    screenpoint = self.mapFromGlobal(QtGui.QCursor.pos())
    dx, dy = screenpoint.x(), screenpoint.y()
    oldpoint = (screenpoint.x() + self.position[0], screenpoint.y() + self.position[1])
    newpoint = (oldpoint[0] * (self.scale/oldscale),
                oldpoint[1] * (self.scale/oldscale))
    self.position = (newpoint[0] - dx, newpoint[1] - dy)
    self.repaint()

def paintEvent(self, event):
    painter = QtGui.QPainter()
    painter.begin(self)

    painter.drawImage(0, 0,
        self.image.scaled(
            self.image.width() * self.scale,
            self.image.height() * self.scale,
            QtCore.Qt.KeepAspectRatio),
        self.position[0], self.position[1])

    painter.end()

app = QtGui.QApplication(sys.argv)
annotator = Annotator()
annotator.show()
sys.exit(app.exec_())

我想在这里插入滚动条。希望我明白这一点。

Answer 1

在PyQt4中有QtGui.QScrollArea允许你使用滚动条调整大小，所以你必须实现这个类，并且在你的def paintEvent (self, eventQPaintEvent)中你已经计算了新的位置并用QWidget.setFixedSize (self, QSize) <调整你的小部件的大小/ p>

完整示例;

from PyQt4 import QtCore, QtGui
import sys

class Annotator (QtGui.QLabel):
    def __init__(self, parentQExampleScrollArea, parentQWidget = None):
        QtGui.QLabel.__init__(self, parentQWidget)
        self.parentQExampleScrollArea = parentQExampleScrollArea
        self.image = None
        self.scale = 1.0
        self.position = (0, 0)
        self.pressed = None
        self.anchor = None
        self.load('myImage.jpg') 

    def load (self, filename):
        self.image = QtGui.QImage(filename)

    def mousePressEvent (self, eventQMouseEvent):
        self.pressed = eventQMouseEvent.pos()
        self.anchor = self.position

    def mouseReleaseEvent (self, eventQMouseEvent):
        self.pressed = None

    def mouseMoveEvent (self, eventQMouseEvent):
        if (self.pressed):
            dx, dy = eventQMouseEvent.x() - self.pressed.x(), eventQMouseEvent.y() - self.pressed.y()
            self.position = (self.anchor[0] - dx, self.anchor[1] - dy)
        self.repaint()

    def wheelEvent (self, eventQWheelEvent):
        oldscale = self.scale
        self.scale += eventQWheelEvent.delta() / 1200.0
        if (self.scale < 0.1):
            self.scale = oldscale
        screenpoint = self.mapFromGlobal(QtGui.QCursor.pos())
        dx, dy = screenpoint.x(), screenpoint.y()
        oldpoint = (screenpoint.x() + self.position[0], screenpoint.y() + self.position[1])
        newpoint = (oldpoint[0] * (self.scale/oldscale), oldpoint[1] * (self.scale/oldscale))
        self.position = (newpoint[0] - dx, newpoint[1] - dy)
        self.repaint()

    def paintEvent (self, eventQPaintEvent):
        scaledQImage = self.image.scaled (
            self.image.width() * self.scale,
            self.image.height() * self.scale,
            QtCore.Qt.KeepAspectRatio)
        painter = QtGui.QPainter()
        painter.begin(self)
        painter.drawImage (
            0,
            0,
            scaledQImage,
            0 if self.position[0] > 0 else self.position[0],
            0 if self.position[1] > 0 else self.position[1])
        painter.end()
        scaledWidth  = self.parentQExampleScrollArea.size().width() - 16 if self.position[0] > 0 else scaledQImage.width()
        scaledHeight = self.parentQExampleScrollArea.size().height() - 16 if self.position[1] > 0 else scaledQImage.height()
        self.setFixedSize(abs(self.position[0]) + scaledWidth, abs(self.position[1]) + scaledHeight)

class QExampleScrollArea (QtGui.QScrollArea):
    def __init__ (self, parentQWidget = None):
        super(QtGui.QScrollArea, self).__init__(parentQWidget)
        self.myAnnotator = Annotator(self)
        self.setWidget(self.myAnnotator)

    def mousePressEvent (self, eventQMouseEvent):
        QtGui.QScrollArea.mousePressEvent(self, eventQMouseEvent)
        self.myAnnotator.mousePressEvent(eventQMouseEvent)

    def mouseReleaseEvent (self, eventQMouseEvent):
        QtGui.QScrollArea.mouseReleaseEvent(self, eventQMouseEvent)
        self.myAnnotator.mouseReleaseEvent(eventQMouseEvent)

    def mouseMoveEvent (self, eventQMouseEvent):
        QtGui.QScrollArea.mouseMoveEvent(self, eventQMouseEvent)
        self.myAnnotator.mouseMoveEvent(eventQMouseEvent)

    def wheelEvent (self, eventQWheelEvent):
        self.myAnnotator.wheelEvent(eventQWheelEvent)

app = QtGui.QApplication(sys.argv)
myQExampleScrollArea = QExampleScrollArea()
myQExampleScrollArea.show()
sys.exit(app.exec_())

注意：建议使用QtGui.QLabel绘制图像

在pyqt4中添加滚动条

1 个答案: