Qpaiter没有

Question

我试图用qpaiter用变量self.lines绘制一些线条，但它做不到。当我试着用手画的时候，其他的东西我都能顺利通过。我的代码是：

import sys, os
from math import pi
from PyQt5.QtWidgets import (QApplication, QWidget, QPushButton, QMenuBar, QMenu, QAction, QHBoxLayout, QFileDialog)
from PyQt5.QtGui import (QPainter, QPen)
from PyQt5.QtCore import (Qt, QPoint, QLineF)

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.coords, self.graph, self.used, self.tin, self.fup, self.con_points = [], [], [], [], [], []
        self.num_of_peaks, self.circle_size, self.timer = 0, 40, 0
        self.algo_starts, self.from_file = False, False
        self.graph_config, self.graph_new = None, None

        self.lines = []

        self.setGeometry(300, 300, 1000, 500)
        self.move(QApplication.desktop().screen().rect().center()-self.rect().center())
        self.setWindowTitle("con point")

        self.menubar = QMenuBar(self)
        self.filemenu = self.menubar.addMenu("File")
        self.newfile = self.filemenu.addAction("New")
        self.openfile = self.filemenu.addAction("Open")
        self.savefile = self.filemenu.addAction("Save")
        self.exitfile = self.filemenu.addAction("Exit")

        self.filemenu.triggered[QAction].connect(self.ProcessTrigger)

        self.startalgobtn = QPushButton("Start", self)
        self.startalgobtn.setGeometry(self.width()-self.startalgobtn.width(), self.menubar.height(),self.startalgobtn.width(), self.startalgobtn.height())
        self.startalgobtn.setVisible(False)

        self.exitbtn = QPushButton("Exit", self)
        self.exitbtn.setGeometry(self.width()-self.startalgobtn.width(), self.menubar.height() + self.exitbtn.height(),self.startalgobtn.width(),
                                 self.startalgobtn.height())
        self.exitbtn.setVisible(False)
        self.exitbtn.clicked.connect(self.Exit)

        self.show()

    def ProcessTrigger(self, q):
        if q == self.newfile: self.NewFile()
        if q == self.openfile: self.OpenFile()
        if q == self.savefile: self.SaveFile()
        if q == self.exitfile: self.Exit()

    def paintEvent(self, a0):
        self.paint_teritory = QPainter(self)
        self.paint_teritory.setRenderHint(QPainter.Antialiasing)
        self.paint_teritory.setBackground(Qt.white)
        self.paint_teritory.setBrush(Qt.black)
        self.paint_teritory.setPen(QPen(Qt.black, 2, Qt.SolidLine))
        self.paint_teritory.drawEllipse(40, 40, 40, 40)
        self.paint_teritory.drawLines(self.lines)

        self.paint_teritory.end()

    def NewFile(self):
        return

    def OpenFile(self):
        self.from_file = True
        self.graph_config = QFileDialog.getOpenFileName(self, "Open File", os.getcwd(), "Text Files (*.txt)")[0]
        self.ReadGraph()

    def SaveFile(self):
        return

    def Exit(self): QApplication.instance().quit()

    def ReadGraph(self):
        if self.from_file:
            with open(self.graph_config) as f: self.graph_config = f.readlines()

            self.num_of_peaks = int(self.graph_config[0])
            self.graph = [[] for x in range(self.num_of_peaks)]

            i = 1
            while self.graph_config[i] != "COORDS\n":
                line = self.graph_config[i].split()
                if len(line) == 1: self.graph[int(line[0])-1] = []
                else: self.graph[int(line[0])-1] = sorted(list(map(int, line[1::])))
                i += 1

            i += 1
            for x in range(i, len(self.graph_config)):
                self.coords.append(list(map(int, self.graph_config[i].split())))

        for i in self.graph:
            for j in i:
                self.lines.append(
                    QLineF(QPoint(self.coords[self.graph.index(i)][0], self.coords[self.graph.index(i)][1]),
                           QPoint(self.coords[j - 1][0], self.coords[j - 1][1])))
        self.conf_yes = True

        self.startalgobtn.setVisible(True)
        self.exitbtn.setVisible(True)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    con_point_app = MainWindow()
    sys.exit(app.exec_())

所以，正如我说的，当我试图用self.lines画图时，什么都没有发生，但是当我用self.paint_teritory.drawEllipse(40, 40, 40, 40)画一个圆时，它实际上出现了。在

以下是我用来测试的文件：https://drive.google.com/file/d/1V4I2okeoE7K_hoClfllYLvFXB78Cjxyh/view?usp=sharing

这就是如何为这个程序制作一个的说明：https://drive.google.com/open?id=1EPxlxUPxH3oWaYJdi9N3RVtC7WPokOCU

Answer 1

问题是，您生成的行的起点和终点是相同的，所以这是无效的，PyQt创建了一个空的QLine。在

此外，绘制线条可能很费力，在这种情况下，最可取的方法是使用QPainterPath，如下所示：

import sys, os
from math import pi
from PyQt5.QtWidgets import (QApplication, QWidget, QPushButton, QMenuBar, QMenu, QAction, QHBoxLayout, QFileDialog)
from PyQt5.QtGui import (QPainter, QPen, QPainterPath)
from PyQt5.QtCore import (Qt, QPointF, QLineF)

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.algo_starts, self.from_file = False, False
        self.graph_config, self.graph_new = None, None

        self.paths = []

        self.setGeometry(300, 300, 1000, 500)
        self.move(QApplication.desktop().screen().rect().center()-self.rect().center())
        self.setWindowTitle("con point")

        self.menubar = QMenuBar(self)
        self.filemenu = self.menubar.addMenu("File")
        self.newfile = self.filemenu.addAction("New")
        self.openfile = self.filemenu.addAction("Open")
        self.savefile = self.filemenu.addAction("Save")
        self.exitfile = self.filemenu.addAction("Exit")

        self.filemenu.triggered[QAction].connect(self.ProcessTrigger)

        self.startalgobtn = QPushButton("Start", self)
        self.startalgobtn.setGeometry(self.width()-self.startalgobtn.width(), self.menubar.height(),self.startalgobtn.width(), self.startalgobtn.height())
        self.startalgobtn.setVisible(False)

        self.exitbtn = QPushButton("Exit", self)
        self.exitbtn.setGeometry(self.width()-self.startalgobtn.width(), self.menubar.height() + self.exitbtn.height(),self.startalgobtn.width(),
                                 self.startalgobtn.height())
        self.exitbtn.setVisible(False)
        self.exitbtn.clicked.connect(self.Exit)

        self.show()

    def ProcessTrigger(self, q):
        if q == self.newfile: self.NewFile()
        if q == self.openfile: self.OpenFile()
        if q == self.savefile: self.SaveFile()
        if q == self.exitfile: self.Exit()

    def paintEvent(self, a0):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        painter.setBackground(Qt.white)
        painter.setBrush(Qt.black)
        painter.setPen(QPen(Qt.black, 2, Qt.SolidLine))
        painter.drawEllipse(40, 40, 40, 40)
        painter.setBrush(Qt.NoBrush)
        for path in self.paths:
            painter.drawPath(path)

    def NewFile(self):
        return

    def OpenFile(self):
        self.from_file = True
        self.graph_config = QFileDialog.getOpenFileName(self, "Open File", os.getcwd(), "Text Files (*.txt)")[0]
        self.ReadGraph()

    def SaveFile(self):
        return

    def Exit(self): QApplication.instance().quit()

    def ReadGraph(self):
        if self.from_file:
            with open(self.graph_config) as f: data = f.readlines()
            num_of_peaks, *info = data
            ix = info.index("COORDS\n")
            vertices_raw = info[:ix]
            coords_raw = info[ix+1:]
            vertices = [list(map(int, vertice.split())) for vertice in vertices_raw]
            coords = [list(map(int, coord.split())) for coord in coords_raw] 

            for vertice in vertices:
                path = QPainterPath()
                for i, p in enumerate(vertice):

                    point = QPointF(*coords[i])
                    if i == 0:
                        path.moveTo(point)
                    else:
                        path.lineTo(point)
                self.paths.append(path)

            self.update()

        self.conf_yes = True

        self.startalgobtn.setVisible(True)
        self.exitbtn.setVisible(True)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    con_point_app = MainWindow()
    sys.exit(app.exec_())