Question

尝试使用PyQt5并使用QPropertyAnimation为从零到（0,0）到（200，200）的线设置动画。我已经阅读了很多有关Qt的文档，并尝试了几个示例，但是我无法使它正常工作。这是我现在拥有的代码：

from PyQt5 import QtCore
from PyQt5.QtWidgets import QApplication, QWidget, QLabel
from PyQt5.QtGui import QPainter, QPixmap, QPainterPath
from PyQt5.QtCore import QObject, QPointF, QPropertyAnimation, pyqtProperty
from PyQt5.QtCore import QLineF
import sys


class Sample(QWidget):

    l1 = QLineF(QPointF(), QPointF())

    def __init__(self):
        super().__init__()

        self.initView()
        self.initAnimation()

    def initView(self):    
        self.show()

    def initAnimation(self):
        self.anim = QPropertyAnimation(self.l1, b'geometry')
        self.anim.setDuration(7000)
        self.anim.setStartValue(QPointF(0, 0))
        self.anim.setEndValue(QPointF(200, 200))
        self.anim.start()

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

不发布所有先前的尝试，每个失败都会失败，并显示不同的错误。我在窗口小部件上使用了淡入淡出的动画来工作，并在路径后绘制了图片，但似乎可以进行简单的线条绘制。我希望实现以下目标：

Codepen example

Qt文档非常庞大，似乎有多种方法可以实现此功能，例如画家和计时器，动画，变体动画，但是我对C ++不太熟悉，并且向Python的转换并不总是那么容易。此外，样本也不是那么容易找到。

我缺少明显的东西吗？

谢谢！

记录下来，这是我到目前为止所取得的成就，但是，一旦我取消对QPropertyAnimation创建的注释，该应用就不会启动。无论如何，我离可接受答案的结果还差得远。

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

class MyLine(QGraphicsLineItem, QObject):
    def __init__(self):
        super().__init__()

    def _set_start(self, point):
        self.setLine(point.x(), point.y(), self.line().p2().x(), self.line().p2().y())

    def _set_end(self, point):
        self.setLine(self.line().p1().x(), self.line().p1().y(), point.x(), point.y())

    start = pyqtProperty(QPointF, fset=_set_start)
    end = pyqtProperty(QPointF, fset=_set_end)


class Example(QWidget):

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        hbox = QHBoxLayout(self)

        self.button = QPushButton("Start", self)
        self.button.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
        hbox.addWidget(self.button)

        hbox.addSpacing(40)

        self.line = MyLine()
        self.line.setLine(0, 0, 10, 10)
        scene = QGraphicsScene()
        scene.addItem(self.line)
        view = QGraphicsView(scene)
        hbox.addWidget(view)

        self.anim = QPropertyAnimation(self.line, b"end") # crash without error here
        # self.anim.setDuration(2500)
        # self.anim.setLoopCount(1)
        # self.anim.setStartValue(QPointF(10, 10))
        # self.anim.setEndValue(QPointF(200, 200))
        # self.button.clicked.connect(self.anim.start)

        self.setGeometry(300, 300, 380, 250)
        self.setWindowTitle('Color anim')
        self.show()


if __name__ == "__main__":

    app = QApplication([])
    ex = Example()
    ex.show()
    app.exec_()

Answer 1

您必须将QGraphicsView和QGraphicsScene与QGraphicsLineItem一起使用，如下所示：

from PyQt5 import QtCore, QtGui, QtWidgets


class LineAnimation(QtCore.QObject):
    def __init__(self, parent=None):
        super(LineAnimation, self).__init__(parent)
        self.m_line = QtCore.QLineF()
        self.m_item = QtWidgets.QGraphicsLineItem()
        self.m_item.setLine(self.m_line)
        self.m_item.setPen(
            QtGui.QPen(
                QtGui.QColor("salmon"),
                10,
                QtCore.Qt.SolidLine,
                QtCore.Qt.SquareCap,
                QtCore.Qt.RoundJoin,
            )
        )

        self.m_animation = QtCore.QPropertyAnimation(
            self,
            b"p2",
            parent=self,
            startValue=QtCore.QPointF(0, 0),
            endValue=QtCore.QPointF(200, 200),
            duration=5 * 1000,
        )
        self.m_animation.start()

    def p1(self):
        return self.m_line.p1()

    def setP1(self, p1):
        self.m_line.setP1(p1)
        self.m_item.setLine(self.m_line)

    def p2(self):
        return self.m_line.p2()

    def setP2(self, p2):
        self.m_line.setP2(p2)
        self.m_item.setLine(self.m_line)

    p1 = QtCore.pyqtProperty(QtCore.QPointF, fget=p1, fset=setP1)
    p2 = QtCore.pyqtProperty(QtCore.QPointF, fget=p2, fset=setP2)


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        scene = QtWidgets.QGraphicsScene(self)
        view = QtWidgets.QGraphicsView(
            scene, alignment=QtCore.Qt.AlignLeft | QtCore.Qt.AlignTop
        )
        self.setCentralWidget(view)

        line_animation = LineAnimation(self)
        scene.addItem(line_animation.m_item)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

使用QPropertyAnimation进行线动画

1 个答案: