动画大小属性时从中心调整小部件的大小

Question

我正在尝试编写一个小部件，该小部件在鼠标悬停时尺寸会略微增大，而在鼠标再次离开时尺寸会减小。
这是我到目前为止想出的：

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

from random import randrange


class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.setFixedSize(500, 500)

        cent_widget = QWidget()
        self.setCentralWidget(cent_widget)

        layout = QVBoxLayout()
        cent_widget.setLayout(layout)

        layout.addWidget(MyItem(), Qt.AlignCenter,
                         alignment=Qt.AlignCenter)


class MyItem(QLabel):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.setBaseSize(200, 250)
        self.setMinimumSize(self.baseSize())
        self.resize(self.baseSize())

        self.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)

        self.setStyleSheet('background: #{:02x}{:02x}{:02x}'.format(
            randrange(255), randrange(255), randrange(255)
        ))

        # Animation
        self._enlarged = False
        self.zoom_factor = 1.2

        self.anim = QPropertyAnimation(self, b'size')
        self.anim.setEasingCurve(QEasingCurve.InOutSine)
        self.anim.setDuration(250)

    def enterEvent(self, event: QEvent) -> None:
        self.resize_anim()
        self._enlarged = True

    def leaveEvent(self, event: QEvent) -> None:
        self.resize_anim()
        self._enlarged = False

    def resize_anim(self):
        if self._enlarged:
            new_size = self.baseSize()
        else:
            new_size = QSize(
                int(self.baseSize().width() * self.zoom_factor),
                int(self.baseSize().height() * self.zoom_factor)
            )
        self.anim.setEndValue(new_size)
        self.anim.start()


if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec()

它几乎按照我想要的方式工作，我唯一的问题是小部件的大小是从 左上角 而不是中心 .
我该如何更改？

Answer 1

不应使用大小属性设置动画，而应使用几何属性，因为它是相对于父小部件的，因此您可以设置其几何的动画，使中心保持不变。

from PyQt5.QtCore import (
    QAbstractAnimation,
    QEasingCurve,
    QEvent,
    QPropertyAnimation,
    QRect,
    Qt,
)
from PyQt5.QtGui import QColor
from PyQt5.QtWidgets import (
    QApplication,
    QLabel,
    QMainWindow,
    QSizePolicy,
    QVBoxLayout,
    QWidget,
)

import random


class MainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.setFixedSize(500, 500)

        cent_widget = QWidget()
        self.setCentralWidget(cent_widget)

        layout = QVBoxLayout(cent_widget)
        layout.addWidget(MyItem(), alignment=Qt.AlignCenter)


class MyItem(QLabel):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.setBaseSize(200, 250)
        self.setMinimumSize(self.baseSize())
        self.resize(self.baseSize())

        self.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)

        self.setStyleSheet(
            "background: {}".format(QColor(*random.sample(range(255), 3)).name())
        )

        # Animation
        self.zoom_factor = 1.2

        self.anim = QPropertyAnimation(self, b"geometry")
        self.anim.setEasingCurve(QEasingCurve.InOutSine)
        self.anim.setDuration(250)

    def enterEvent(self, event: QEvent) -> None:

        initial_rect = self.geometry()
        final_rect = QRect(
            0,
            0,
            int(initial_rect.width() * self.zoom_factor),
            int(initial_rect.height() * self.zoom_factor),
        )
        final_rect.moveCenter(initial_rect.center())

        self.anim.setStartValue(initial_rect)
        self.anim.setEndValue(final_rect)
        self.anim.setDirection(QAbstractAnimation.Forward)
        self.anim.start()

    def leaveEvent(self, event: QEvent) -> None:
        self.anim.setDirection(QAbstractAnimation.Backward)
        self.anim.start()


if __name__ == "__main__":
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec()

动画大小属性时从中心调整小部件的大小

Resize widget from center when animating the size property

python

pyqt5

resize

qpropertyanimation

动画大小 属性 时从中心调整小部件的大小

Resize widget from center when animating the size property

python

pyqt5

resize

qpropertyanimation

动画大小属性时从中心调整小部件的大小