关于python:用pyqt5逐步绘制的正确方法

Correct way to paint progressively with pyqt5

我有一个基本上是圆形的小部件。我想逐步绘制它,所以我需要逐步绘制它(imo)。

通过以下代码,我已经实现了我想要的。但是,有一个问题。我正在将一个新事件传递给 paintEvent 函数,因为如果我不这样做,图像不会在一切都完成之前得到更新,所以我没有得到任何我想要的结果。

小部件代码

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import sys
import time
from PyQt5.QtCore import Qt, QRect
from PyQt5.QtWidgets import QApplication, QWidget, QCheckBox, QDesktopWidget

from PyQt5.QtGui import QPen, QPainter, QPaintEvent, QConicalGradient, QColor, QBrush

class Circle(QWidget):

    def __init__(self, size, color):
        super().__init__()

        self.loadingAngle = 0
        self.width = 0
        self.color = color
        self.pixmap_opacity = 1

        self.resize(size, size);
        self.center()

        self.initUI()

    def initUI(self):

        self.width = 15
        self.loadingAngle = 0
        self.show()

    def center(self):
        qr = self.frameGeometry()
        cp = QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())

    def paintEvent(self, qevent):

        self.setWindowFlags(Qt.FramelessWindowHint)
        self.setAttribute(Qt.WA_TranslucentBackground)
        self.setStyleSheet("background:transparent;")

        drawingRect = QRect()
        drawingRect.setX(qevent.rect().x() + self.width)
        drawingRect.setY(qevent.rect().y() + self.width)
        drawingRect.setWidth(qevent.rect().width() - self.width * 2)
        drawingRect.setHeight(qevent.rect().height() - self.width * 2)

        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)

        gradient = QConicalGradient()
        gradient.setCenter(drawingRect.center())
        gradient.setAngle(90)
        gradient.setColorAt(1, QColor(0,0,0))
        gradient.setColorAt(0, QColor(self.color[0], self.color[1],self.color[2]))

        arcLengthApproximation = self.width + self.width / 3
        pen = QPen(QBrush(gradient), self.width)
        pen.setCapStyle(Qt.RoundCap)
        painter.setPen(pen)
        painter.drawArc(drawingRect, 90 * 16 - arcLengthApproximation, -self.loadingAngle * 16)
        #time.sleep(0.25)

        if self.loadingAngle < 360:
            self.loadingAngle += 1
            #self.paintEvent(QDrawEvent())
            self.paintEvent(QPaintEvent())

有问题的线路

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self.paintEvent(QPaintEvent())

这条线产生了几个错误,但即使有它们,我也会做我想做的。

  • 如果我将 qevent 从函数本身传递给这个新调用,图像不会像我之前所说的那样得到更新。

  • 如果我创建这个新的 QPaintEvent,它确实有效。但是,错误是:

  • Traceback (most recent call last):

    File"/home/btc/Escritorio/SinestesiaRCB/Clases/Widget.py", line 68, in
    paintEvent self.paintEvent(QPaintEvent())

    TypeError: arguments did not match any overloaded call:
    QPaintEvent(QRegion): not enough arguments

    QPaintEvent(QRect): not enough arguments

    QPaintEvent(QPaintEvent): not enough arguments

    QBackingStore::endPaint() called with active painter on backingstore paint device

    这些错误可能来自其他行,例如:

    1
    qevent.rect().x()

    因为新事件是空的。

    所以基本上我的问题是,我应该怎么做才能正确地做到这一点,这意味着没有错误地实现我想要的?

    PS。我所说的渐进式。这已经创建了几个小部件,每个小部件都在前一秒之后。

    enter

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    import sys
    from PyQt5 import QtCore, QtGui, QtWidgets

    class Circle(QtWidgets.QWidget):
        def __init__(self, size, color):
            super().__init__()
            self._loading_angle = 0
            self.width = 0
            self.color = color
            self.pixmap_opacity = 1
            self.resize(size, size)
            self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
            self.setAttribute(QtCore.Qt.WA_TranslucentBackground)
            self.setStyleSheet("background:transparent;")
            self.center()
            self.initUI()

            timeline = QtCore.QTimeLine(4000, self)
            timeline.setFrameRange(0, 360)
            timeline.frameChanged.connect(self.setLoadingAngle)
            timeline.start()

        def initUI(self):
            self.width = 15
            self.setLoadingAngle(0)
            self.show()

        def loadingAngle(self):
            return self._loading_angle

        def setLoadingAngle(self, angle):
            self._loading_angle = angle
            self.update()

        loadingAngle = QtCore.pyqtProperty(int, fget=loadingAngle, fset=setLoadingAngle)

        def center(self):
            qr = self.frameGeometry()
            cp = QtWidgets.QDesktopWidget().availableGeometry().center()
            qr.moveCenter(cp)
            self.move(qr.topLeft())

        def paintEvent(self, event):
            painter = QtGui.QPainter(self)
            painter.setRenderHint(QtGui.QPainter.Antialiasing)
            drawingRect  = QtCore.QRect(QtCore.QPoint(), self.rect().size() - 2*self.width*QtCore.QSize(1, 1))
            drawingRect.moveCenter(self.rect().center())

            gradient = QtGui.QConicalGradient()
            gradient.setCenter(drawingRect.center())
            gradient.setAngle(90)
            gradient.setColorAt(1, QtGui.QColor(0,0,0))
            gradient.setColorAt(0, self.color)
            arcLengthApproximation = self.width + self.width / 3
            pen = QtGui.QPen(QtGui.QBrush(gradient), self.width)
            pen.setCapStyle(QtCore.Qt.RoundCap)
            painter.setPen(pen)
            painter.drawArc(drawingRect, 90 * 16 - arcLengthApproximation, -self._loading_angle * 16)


    if __name__ == '__main__':
        import sys
        app = QtWidgets.QApplication(sys.argv)
        w = Circle(400, QtGui.QColor("blue"))
        w.show()
        sys.exit(app.exec_())