使用PyQt绘制由多个点组成的线 [英] Drawing a line consisting of multiple points using PyQt

问题描述

我想使用PyQt通过在Python脚本中单击鼠标来绘制由多个点组成的线。我需要所有点的坐标，并且我希望能够删除这条线。这是我的脚本完成所有工作，除了图形线条图本身，它只是打印其工作内容：

I want to draw a line consisting of multiple points via mouse click in a Python script using PyQt. I need all coordinates of the ponts and I want to be able to delete the line. Here's my script doing all the work, except for the graphical line drawing itself, it just prints what it does:

#!/usr/bin/python3

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

class endomess(QMainWindow):

    def __init__(self):
        QMainWindow.__init__(self)
        self.draw = False

    def mousePressEvent(self, event):

        if event.button() == Qt.LeftButton:

            if self.draw == False:
                print('Starting to draw at', str(event.pos()))
                self.draw = True
                self.linePoints = []

            elif self.draw == True:
                print('Appending', str(event.pos()))

            self.linePoints.append(event.pos())

        elif event.button() == Qt.RightButton:
            if self.draw == True:
                print('Finished drawing. List of all points:', str(self.linePoints))
                self.draw = False

def main(argv):
    app = QApplication(argv, True)
    wnd = endomess()
    wnd.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main(sys.argv)

所以，这是我的问题：我实际上如何画出可以通过上面的脚本定义？我已经看过scribble.py和一些Qt绘画文档，但是我不明白。

So, here's my problem: how do I actually draw that line that can be defined via the above script? I already had a look at scribble.py and some Qt paint docs, but I don't get it. Probably, this is not a problem for someone more experienced with Qt?

预先感谢所有帮助！

推荐答案

您可能应该使用图形视图框架绘制线条，而不是尝试直接绘制线条。

You should probably use the graphics view framework for drawing the lines, rather than attempting to paint them directly.

以下是入门的基本演示：

Here's a basic demo to get you started:

from PyQt4 import QtGui, QtCore

class Window(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)
        self.view = View(self)
        self.button = QtGui.QPushButton('Clear View', self)
        self.button.clicked.connect(self.handleClearView)
        layout = QtGui.QVBoxLayout(self)
        layout.addWidget(self.view)
        layout.addWidget(self.button)

    def handleClearView(self):
        self.view.scene().clear()

class View(QtGui.QGraphicsView):
    def __init__(self, parent):
        QtGui.QGraphicsView.__init__(self, parent)
        self.setScene(QtGui.QGraphicsScene(self))
        self.setSceneRect(QtCore.QRectF(self.viewport().rect()))

    def mousePressEvent(self, event):
        self._start = event.pos()

    def mouseReleaseEvent(self, event):
        start = QtCore.QPointF(self.mapToScene(self._start))
        end = QtCore.QPointF(self.mapToScene(event.pos()))
        self.scene().addItem(
            QtGui.QGraphicsLineItem(QtCore.QLineF(start, end)))
        for point in (start, end):
            text = self.scene().addSimpleText(
                '(%d, %d)' % (point.x(), point.y()))
            text.setBrush(QtCore.Qt.red)
            text.setPos(point)

if __name__ == '__main__':

    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.resize(640, 480)
    window.show()
    sys.exit(app.exec_())

这篇关于使用PyQt绘制由多个点组成的线的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！