PyQT5:如何在 QLabel Widget 中以交互方式在图像上绘画? [英] PyQT5: How to interactively paint on image within QLabel Widget?

问题描述

Python 3，Mac OS Mojave 上最新版本的 PyQt5

Python 3, latest version of PyQt5 on Mac OS Mojave

我想要一个 PyQt5 程序，在该程序中，用户可以在图像上绘制连接的点(独特地单击，这些点会自动连接).重要的是，我只能在 QLabel 小部件(或替代小部件)中的图像上绘制，而不能在整个主窗口上绘制.

I want a PyQt5 program in which the user could paint connected dots on an image (click distinctively and the points are automatically connected). It is important that I can only draw on the image in the QLabel widget (or an alternative widget) and not over the entire main window.

我可以绘制图像并获得前两次点击的坐标，但是当我想在图像上绘画时，它发生在图像下方.此外，我无法将坐标作为我的paintevent 的输入.

I can plot the image and get the the coordinates of the previous two clicks but when I want to paint on the image it happens underneath the image. Further I have troubles in getting the coordinates as input for my paintevent.

class Example(QWidget):

   def __init__(self):

      super().__init__()


      title = "Darcy"
      top = 400
      left = 400
      width = 550
      height = 600

      self.clickcount = 0
      self.x = 0
      self.y = 0



      self.setWindowTitle(title)
      self.setGeometry(top,left, width, height)

      self.initUI()

  def paintEvent(self, e):

      qp = QPainter()
      qp.begin(self)
      self.drawLines(qp)
      qp.end()


  def drawLines(self, qp):

      pen = QPen(Qt.black, 2, Qt.SolidLine)

      qp.setPen(pen)
      qp.drawLine(20, 40, 250, 40)

  def initUI(self):

      self.map = QLabel()
      Im = QPixmap("GM_loc.png")
      Im = Im.scaled(450,450)
      self.map.setPixmap(Im)

      self.loc = QLabel()
      self.test = QLabel()

      self.map.mousePressEvent = self.getPos



      #organize in grid
      grid = QGridLayout()
      grid.setSpacing(10)

      grid.addWidget(self.map, 0, 0)
      grid.addWidget(self.loc,1,0)
      grid.addWidget(self.test,2,0)

      self.setLayout(grid)
      self.show()


  def getPos(self , event):

      self.clickcount += 1

      self.x_old = self.x
      self.y_old = self.y

      self.x = event.pos().x()
      self.y = event.pos().y() 


      self.loc.setText("x = "+str(self.x)+" & y= "+str(self.y)+" & old x = " + str(self.x_old) + " & old y = " + str(self.y_old))


 if __name__ == '__main__':

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

提前致谢！PS 我是 PyQt5 的菜鸟，所以非常欢迎任何关于更高效代码的提示！

Thanks in advance! PS I am a rookie in PyQt5 so any hints in more efficient code are more than welcome!

推荐答案

试试看:

import sys
from PyQt5.QtCore    import *
from PyQt5.QtWidgets import *
from PyQt5.QtGui     import *

class MyScribbling(QMainWindow):
    def __init__(self):
        super().__init__()
        self.penOn = QAction(QIcon('Image/ok.png'), 'ON   drawing', self)
        self.penOn.triggered.connect(self.drawingOn)
        self.penOff = QAction(QIcon('Image/exit.png'), 'OFF drawing', self)
        self.penOff.triggered.connect(self.drawingOff)
        toolbar = self.addToolBar('Tools')
        toolbar.addAction(self.penOn)
        toolbar.addAction(self.penOff)

        self.scribbling = False
        self.myPenColor = Qt.red      
        self.myPenWidth = 3           

        self.lastPoint = QPoint()
        self.image     = QPixmap("Image/picture.png")
        self.setFixedSize(600, 600)
        self.resize(self.image.width(), self.image.height())
        self.setWindowTitle("drawing On / Off")

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.drawPixmap(self.rect(), self.image)

    def mousePressEvent(self, event):
        if (event.button() == Qt.LeftButton) and self.scribbling: 
            self.lastPoint = event.pos()

    def mouseMoveEvent(self, event):
        if (event.buttons() & Qt.LeftButton) and self.scribbling:
            painter = QPainter(self.image)
            painter.setPen(QPen(self.myPenColor, self.myPenWidth, 
                                Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
            painter.drawLine(self.lastPoint, event.pos())
            self.lastPoint = event.pos()
            self.update()

    def drawingOn(self):
        self.scribbling = True

    def drawingOff(self):
        self.scribbling = False

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = MyScribbling()
    ex.show()
    sys.exit(app.exec_())        

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