如何结合这两个代码?(python图像查看器+鼠标拖动

问题描述

我是 Python 和 PyQt 的初学者.我尝试基于 acbetter 的代码创建图像查看器，并希望添加图像裁剪功能.使用这两个代码，最终我想创建一个代码，我可以在其中打开某个图像并裁剪图像的特定部分并将其显示在另一个窗口中.您想帮忙如何组合这两个代码吗?

1. acbetter 的图片查看器代码

   I'm beginner in Python and PyQt. I try to create image viewer based on acbetter's code and want to add image crop function. Using these two codes, ultimately I want to create a code in which I can open a certain image and crop specific part of the image and show it in another window. Would you like to help how to combine these two codes?

   1. acbetter's image viewer code https://gist.github.com/acbetter/32c575803ec361c3e82064e60db4e3e0

   from PyQt5.QtCore import Qt
   from PyQt5.QtGui import QImage, QPixmap, QPalette, QPainter
   from PyQt5.QtPrintSupport import QPrintDialog, QPrinter
   from PyQt5.QtWidgets import QLabel, QSizePolicy, QScrollArea, QMessageBox, QMainWindow, QMenu, QAction, 
       qApp, QFileDialog
   
   
   class QImageViewer(QMainWindow):
       def __init__(self):
           super().__init__()
   
           self.printer = QPrinter()
           self.scaleFactor = 0.0
   
           self.imageLabel = QLabel()
           self.imageLabel.setBackgroundRole(QPalette.Base)
           self.imageLabel.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
           self.imageLabel.setScaledContents(True)
   
           self.scrollArea = QScrollArea()
           self.scrollArea.setBackgroundRole(QPalette.Dark)
           self.scrollArea.setWidget(self.imageLabel)
           self.scrollArea.setVisible(False)
   
           self.setCentralWidget(self.scrollArea)
   
           self.createActions()
           self.createMenus()
   
           self.setWindowTitle("Image Viewer")
           self.resize(800, 600)
   
       def open(self):
           options = QFileDialog.Options()
           # fileName = QFileDialog.getOpenFileName(self, "Open File", QDir.currentPath())
           fileName, _ = QFileDialog.getOpenFileName(self, 'QFileDialog.getOpenFileName()', '',
                                                     'Images (*.png *.jpeg *.jpg *.bmp *.gif)', options=options)
           if fileName:
               image = QImage(fileName)
               if image.isNull():
                   QMessageBox.information(self, "Image Viewer", "Cannot load %s." % fileName)
                   return
   
               self.imageLabel.setPixmap(QPixmap.fromImage(image))
               self.scaleFactor = 1.0
   
               self.scrollArea.setVisible(True)
               self.printAct.setEnabled(True)
               self.fitToWindowAct.setEnabled(True)
               self.updateActions()
   
               if not self.fitToWindowAct.isChecked():
                   self.imageLabel.adjustSize()
   
       def print_(self):
           dialog = QPrintDialog(self.printer, self)
           if dialog.exec_():
               painter = QPainter(self.printer)
               rect = painter.viewport()
               size = self.imageLabel.pixmap().size()
               size.scale(rect.size(), Qt.KeepAspectRatio)
               painter.setViewport(rect.x(), rect.y(), size.width(), size.height())
               painter.setWindow(self.imageLabel.pixmap().rect())
               painter.drawPixmap(0, 0, self.imageLabel.pixmap())
   
       def zoomIn(self):
           self.scaleImage(1.25)
   
       def zoomOut(self):
           self.scaleImage(0.8)
   
       def normalSize(self):
           self.imageLabel.adjustSize()
           self.scaleFactor = 1.0
   
       def fitToWindow(self):
           fitToWindow = self.fitToWindowAct.isChecked()
           self.scrollArea.setWidgetResizable(fitToWindow)
           if not fitToWindow:
               self.normalSize()
   
           self.updateActions()
   
       def about(self):
           QMessageBox.about(self, "About Image Viewer",
                             "<p>The <b>Image Viewer</b> example shows how to combine "
                             "QLabel and QScrollArea to display an image. QLabel is "
                             "typically used for displaying text, but it can also display "
                             "an image. QScrollArea provides a scrolling view around "
                             "another widget. If the child widget exceeds the size of the "
                             "frame, QScrollArea automatically provides scroll bars.</p>"
                             "<p>The example demonstrates how QLabel's ability to scale "
                             "its contents (QLabel.scaledContents), and QScrollArea's "
                             "ability to automatically resize its contents "
                             "(QScrollArea.widgetResizable), can be used to implement "
                             "zooming and scaling features.</p>"
                             "<p>In addition the example shows how to use QPainter to "
                             "print an image.</p>")
   
       def createActions(self):
           self.openAct = QAction("&Open...", self, shortcut="Ctrl+O", triggered=self.open)
           self.printAct = QAction("&Print...", self, shortcut="Ctrl+P", enabled=False, triggered=self.print_)
           self.exitAct = QAction("E&xit", self, shortcut="Ctrl+Q", triggered=self.close)
           self.zoomInAct = QAction("Zoom &In (25%)", self, shortcut="Ctrl++", enabled=False, triggered=self.zoomIn)
           self.zoomOutAct = QAction("Zoom &Out (25%)", self, shortcut="Ctrl+-", enabled=False, triggered=self.zoomOut)
           self.normalSizeAct = QAction("&Normal Size", self, shortcut="Ctrl+S", enabled=False, triggered=self.normalSize)
           self.fitToWindowAct = QAction("&Fit to Window", self, enabled=False, checkable=True, shortcut="Ctrl+F",
                                         triggered=self.fitToWindow)
           self.aboutAct = QAction("&About", self, triggered=self.about)
           self.aboutQtAct = QAction("About &Qt", self, triggered=qApp.aboutQt)
   
       def createMenus(self):
           self.fileMenu = QMenu("&File", self)
           self.fileMenu.addAction(self.openAct)
           self.fileMenu.addAction(self.printAct)
           self.fileMenu.addSeparator()
           self.fileMenu.addAction(self.exitAct)
   
           self.viewMenu = QMenu("&View", self)
           self.viewMenu.addAction(self.zoomInAct)
           self.viewMenu.addAction(self.zoomOutAct)
           self.viewMenu.addAction(self.normalSizeAct)
           self.viewMenu.addSeparator()
           self.viewMenu.addAction(self.fitToWindowAct)
   
           self.helpMenu = QMenu("&Help", self)
           self.helpMenu.addAction(self.aboutAct)
           self.helpMenu.addAction(self.aboutQtAct)
   
           self.menuBar().addMenu(self.fileMenu)
           self.menuBar().addMenu(self.viewMenu)
           self.menuBar().addMenu(self.helpMenu)
   
       def updateActions(self):
           self.zoomInAct.setEnabled(not self.fitToWindowAct.isChecked())
           self.zoomOutAct.setEnabled(not self.fitToWindowAct.isChecked())
           self.normalSizeAct.setEnabled(not self.fitToWindowAct.isChecked())
   
       def scaleImage(self, factor):
           self.scaleFactor *= factor
           self.imageLabel.resize(self.scaleFactor * self.imageLabel.pixmap().size())
   
           self.adjustScrollBar(self.scrollArea.horizontalScrollBar(), factor)
           self.adjustScrollBar(self.scrollArea.verticalScrollBar(), factor)
   
           self.zoomInAct.setEnabled(self.scaleFactor < 3.0)
           self.zoomOutAct.setEnabled(self.scaleFactor > 0.333)
   
       def adjustScrollBar(self, scrollBar, factor):
           scrollBar.setValue(int(factor * scrollBar.value()
                                  + ((factor - 1) * scrollBar.pageStep() / 2)))
   
   
   if __name__ == '__main__':
       import sys
       from PyQt5.QtWidgets import QApplication
   
       app = QApplication(sys.argv)
       imageViewer = QImageViewer()
       imageViewer.show()
       sys.exit(app.exec_())
   

   2. image crop code using opencv

   import cv2 
   mouse_is_pressing = False
   start_x, start_y = -1, -1
   
   def mouse_callback(event, x, y, flags, param):
       global start_x, start_y, mouse_is_pressing 
   
       img_result = src.copy()
   
       if event == cv2.EVENT_LBUTTONDOWN:
   
           mouse_is_pressing = True
           start_x, start_y = x,y
   
           cv2.circle(img_result, (x,y), 10, (0,255,0),-1)
           cv2.imshow("img_color", img_result)
   
       elif event == cv2.EVENT_MOUSEMOVE:
           if mouse_is_pressing: 
               cv2.rectangle(img_result, (start_x, start_y), (x,y), (0,255,0), 3)
               cv2.imshow("img_color", img_result)
   
       elif event == cv2.EVENT_LBUTTONUP:
           mouse_is_pressing = False 
   
           img_part = img_result[start_y:y, start_x:x]
           cv2.imshow("img_color", img_result)
           cv2.imshow("img_part", img_part)
   
   src = cv2.imread("D:/python data/image/image.jpg")
   cv2.imshow("img_color", src)
   cv2.setMouseCallback("img_color", mouse_callback)
   cv2.waitKey(0)
   cv2.destroyAllWindows()
   

   解决方案

   Implementing the crop in a viewer based on a QScrollArea with a QLabel is unnecessarily complicated since the transformation is complicated to track, instead implement the same logic with QGraphicsView, QGraphicsScene and QGraphicsPixmapItem. So much of the logic is already implemented as I show below:

   from PyQt5 import QtCore, QtGui, QtWidgets, QtPrintSupport
   
   
   class Viewer(QtWidgets.QGraphicsView):
       def __init__(self, parent=None):
           super().__init__(QtWidgets.QGraphicsScene(), parent)
           self.pixmap_item = self.scene().addPixmap(QtGui.QPixmap())
           self.setAlignment(QtCore.Qt.AlignTop | QtCore.Qt.AlignLeft)
           self.setBackgroundRole(QtGui.QPalette.Dark)
           self.setDragMode(QtWidgets.QGraphicsView.RubberBandDrag)
           self.rubberBandChanged.connect(self.onRubberBandChanged)
           self.last_rect = QtCore.QPointF()
   
       def setPixmap(self, pixmap):
           self.pixmap_item.setPixmap(pixmap)
   
       def zoomIn(self):
           self.scale(1.25, 1.25)
   
       def zoomOut(self):
           self.scale(0.8, 0.8)
   
       def resetZoom(self):
           self.resetTransform()
   
       def fitToWindow(self):
           self.fitInView(self.pixmap_item)
   
       @QtCore.pyqtSlot(QtCore.QRect, QtCore.QPointF, QtCore.QPointF)
       def onRubberBandChanged(self, rubberBandRect, fromScenePoint, toScenePoint):
           if rubberBandRect.isNull():
               pixmap = self.pixmap_item.pixmap()
               rect = self.pixmap_item.mapFromScene(self.last_rect).boundingRect().toRect()
               if not rect.intersected(pixmap.rect()).isNull():
                   crop_pixmap = pixmap.copy(rect)
                   label = QtWidgets.QLabel(pixmap=crop_pixmap)
                   dialog = QtWidgets.QDialog(self)
                   lay = QtWidgets.QVBoxLayout(dialog)
                   lay.addWidget(label)
                   dialog.exec_()
               self.last_rect = QtCore.QRectF()
           else:
               self.last_rect = QtCore.QRectF(fromScenePoint, toScenePoint)
   
   
   class QImageViewer(QtWidgets.QMainWindow):
       def __init__(self, parent=None):
           super().__init__()
   
           self.view = Viewer()
           self.setCentralWidget(self.view)
   
           self.printer = QtPrintSupport.QPrinter()
   
           self.createActions()
           self.createMenus()
   
           self.setWindowTitle("Image Viewer")
           self.resize(800, 600)
   
       def open(self):
           fileName, _ = QtWidgets.QFileDialog.getOpenFileName(
               self,
               "QFileDialog.getOpenFileName()",
               "",
               "Images (*.png *.jpeg *.jpg *.bmp *.gif)",
           )
           if fileName:
               pixmap = QtGui.QPixmap(fileName)
               if pixmap.isNull():
                   QtWidgets.QMessageBox.information(
                       self, "Image Viewer", "Cannot load %s." % fileName
                   )
                   return
   
               self.view.setPixmap(pixmap)
   
               self.printAct.setEnabled(True)
               self.fitToWindowAct.setEnabled(True)
               self.updateActions()
   
               if not self.fitToWindowAct.isChecked():
                   pass
                   # self.imageLabel.adjustSize()
   
       def print_(self):
           dialog = QtPrintSupport.QPrintDialog(self.printer, self)
           if dialog.exec_():
               pixmap = self.view.pixmap_item.pixmap()
               painter = QtGui.QPainter(self.printer)
               rect = painter.viewport()
               size = pixmap.size()
               size.scale(rect.size(), QtCore.Qt.KeepAspectRatio)
               painter.setViewport(rect.x(), rect.y(), size.width(), size.height())
               painter.setWindow(pixmap.rect())
               painter.drawPixmap(0, 0, pixmap)
   
       def fitToWindow(self):
           if self.fitToWindowAct.isChecked():
               self.view.fitToWindow()
           else:
               self.view.resetZoom()
           self.updateActions()
   
       def about(self):
           QtWidgets.QMessageBox.about(
               self,
               "About Image Viewer",
               "<p>The <b>Image Viewer</b> example shows how to combine "
               "QLabel and QScrollArea to display an image. QLabel is "
               "typically used for displaying text, but it can also display "
               "an image. QScrollArea provides a scrolling view around "
               "another widget. If the child widget exceeds the size of the "
               "frame, QScrollArea automatically provides scroll bars.</p>"
               "<p>The example demonstrates how QLabel's ability to scale "
               "its contents (QLabel.scaledContents), and QScrollArea's "
               "ability to automatically resize its contents "
               "(QScrollArea.widgetResizable), can be used to implement "
               "zooming and scaling features.</p>"
               "<p>In addition the example shows how to use QPainter to "
               "print an image.</p>",
           )
   
       def createActions(self):
           self.openAct = QtWidgets.QAction(
               "&Open...", self, shortcut="Ctrl+O", triggered=self.open
           )
           self.printAct = QtWidgets.QAction(
               "&Print...", self, shortcut="Ctrl+P", enabled=False, triggered=self.print_
           )
           self.exitAct = QtWidgets.QAction(
               "E&xit", self, shortcut="Ctrl+Q", triggered=self.close
           )
           self.zoomInAct = QtWidgets.QAction(
               "Zoom &In (25%)",
               self,
               shortcut="Ctrl++",
               enabled=False,
               triggered=self.view.zoomIn,
           )
           self.zoomOutAct = QtWidgets.QAction(
               "Zoom &Out (25%)",
               self,
               shortcut="Ctrl+-",
               enabled=False,
               triggered=self.view.zoomOut,
           )
           self.normalSizeAct = QtWidgets.QAction(
               "&Normal Size",
               self,
               shortcut="Ctrl+S",
               enabled=False,
               triggered=self.view.resetZoom,
           )
           self.fitToWindowAct = QtWidgets.QAction(
               "&Fit to Window",
               self,
               enabled=False,
               checkable=True,
               shortcut="Ctrl+F",
               triggered=self.fitToWindow,
           )
           self.aboutAct = QtWidgets.QAction("&About", self, triggered=self.about)
           self.aboutQtAct = QtWidgets.QAction(
               "About &Qt", self, triggered=QtWidgets.qApp.aboutQt
           )
   
       def createMenus(self):
           self.fileMenu = QtWidgets.QMenu("&File", self)
           self.fileMenu.addAction(self.openAct)
           self.fileMenu.addAction(self.printAct)
           self.fileMenu.addSeparator()
           self.fileMenu.addAction(self.exitAct)
   
           self.viewMenu = QtWidgets.QMenu("&View", self)
           self.viewMenu.addAction(self.zoomInAct)
           self.viewMenu.addAction(self.zoomOutAct)
           self.viewMenu.addAction(self.normalSizeAct)
           self.viewMenu.addSeparator()
           self.viewMenu.addAction(self.fitToWindowAct)
   
           self.helpMenu = QtWidgets.QMenu("&Help", self)
           self.helpMenu.addAction(self.aboutAct)
           self.helpMenu.addAction(self.aboutQtAct)
   
           self.menuBar().addMenu(self.fileMenu)
           self.menuBar().addMenu(self.viewMenu)
           self.menuBar().addMenu(self.helpMenu)
   
       def updateActions(self):
           self.zoomInAct.setEnabled(not self.fitToWindowAct.isChecked())
           self.zoomOutAct.setEnabled(not self.fitToWindowAct.isChecked())
           self.normalSizeAct.setEnabled(not self.fitToWindowAct.isChecked())
   
   
   if __name__ == "__main__":
       import sys
       from PyQt5.QtWidgets import QApplication
   
       app = QApplication(sys.argv)
       imageViewer = QImageViewer()
       imageViewer.show()
       sys.exit(app.exec_())
   

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