如何裁剪图像并保存？

Question

我打开了一张图片QHBoxLayout.我需要裁剪打开的图像并保存裁剪的图像.我怎样才能在PySide中做到这一点？

import sys
from PySide import QtGui, QtCore

class Example(QtGui.QWidget):

    def __init__(self):
        super(Example, self).__init__()

        self.initUI()

    def initUI(self):      

        hbox = QtGui.QHBoxLayout(self)
        pixmap = QtGui.QPixmap("re.png")

        lbl = QtGui.QLabel(self)
        lbl.setPixmap(pixmap)


        self.rect = QtCore.QRect()


        hbox.addWidget(lbl)
        self.setLayout(hbox)

        self.setGeometry(300, 300, 280, 170)
        self.setWindowTitle('Open Image')
        self.show()   
        # Tried here to implement Qpen      
        #self.painter = QtGui.QPainter(self)    
        #self.painter.setPen(QtGui.QPen(QtCore.Qt.black, 1, QtCore.Qt.SolidLine));
        #self.painter.drawRect(self.rect);
def main():

    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

Answer 1

我建议用class QtGui.QRubberBand来选择要裁剪的图像区域.(PySide aslo实现相同的PyQt)

首先,实施方法mouseMoveEvent (self, QMouseEvent),mouseReleaseEvent (self, QMouseEvent)和mousePressEvent (self, QMouseEvent)(更多信息在读QtGui.QRubberBand类参考).

接下来,QtGui.QRubberBand通过使用获取裁剪图像的最后几何图形QRect QWidget.geometry (self).

最后,用于QPixmap QPixmap.copy (self, QRect rect = QRect())通过从裁剪区域放置几何图形来裁剪图像.并使用保存图像bool QPixmap.save (self, QString fileName, str format = None, int quality = -1).

例;

import sys
from PyQt4 import QtGui, QtCore

class QExampleLabel (QtGui.QLabel):
    def __init__(self, parentQWidget = None):
        super(QExampleLabel, self).__init__(parentQWidget)
        self.initUI()

    def initUI (self):
        self.setPixmap(QtGui.QPixmap('input.png'))

    def mousePressEvent (self, eventQMouseEvent):
        self.originQPoint = eventQMouseEvent.pos()
        self.currentQRubberBand = QtGui.QRubberBand(QtGui.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()
        self.currentQRubberBand.deleteLater()
        cropQPixmap = self.pixmap().copy(currentQRect)
        cropQPixmap.save('output.png')

if __name__ == '__main__':
    myQApplication = QtGui.QApplication(sys.argv)
    myQExampleLabel = QExampleLabel()
    myQExampleLabel.show()
    sys.exit(myQApplication.exec_())