如何在小部件上使用按键输入制作缩放效果?该小部件位于滚动区域内,并且有一些使用 QPainter 绘制的绘图会随着用户输入而变化。缩放会影响滚动条的长度,距离越近,滚动条越小。最小级别的缩放应该使滚动条与小部件区域一样大,这样小部件中的所有内容都可以被可视化。
MRE:
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QWidget
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPainter, QPen, QColor
import sys
class Diedrico(QWidget):
def __init__(self, parent):
super().__init__(parent)
def paintEvent(self, event):
qp = QPainter(self)
qp.setPen(QPen(QColor(Qt.black), 5))
qp.drawRect(500, 500, 1000, 1000)
class UiVentana(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self.resize(520, 520)
self.widget_central = QtWidgets.QWidget(self)
scrol = QtWidgets.QScrollArea(self.widget_central)
scrol.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
scrol.setGeometry(QtCore.QRect(10, 10, 500, 500))
scrol.setWidgetResizable(False)
contenido = QtWidgets.QWidget()
contenido.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
scrol.setWidget(contenido)
self.Diedrico = Diedrico(contenido)
self.Diedrico.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
self.setCentralWidget(self.widget_central)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
最佳答案
您为什么要重新发明轮子?不要想实现缩放功能的逻辑,而是使用已经实现的类。在这种情况下,一个好的选择是将 QGraphicsView 与 QGraphicsScene 结合使用:
注意:快捷键标准放大和缩小与 Ctrl + + 和 Ctrl + -,分别。
from PyQt5 import QtCore, QtGui, QtWidgets
class Diedrico(QtWidgets.QWidget):
def paintEvent(self, event):
qp = QtGui.QPainter(self)
pen = QtGui.QPen(QtGui.QColor(QtCore.Qt.black), 5)
qp.setPen(pen)
qp.drawRect(500, 500, 1000, 1000)
class UiVentana(QtWidgets.QMainWindow):
factor = 1.5
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self._view = QtWidgets.QGraphicsView(self._scene)
self._diedrico = Diedrico()
self._diedrico.setFixedSize(2000, 2000)
self._scene.addWidget(self._diedrico)
self.setCentralWidget(self._view)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtGui.QKeySequence.ZoomIn),
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_in,
)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtGui.QKeySequence.ZoomOut),
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_out,
)
@QtCore.pyqtSlot()
def zoom_in(self):
scale_tr = QtGui.QTransform()
scale_tr.scale(UiVentana.factor, UiVentana.factor)
tr = self._view.transform() * scale_tr
self._view.setTransform(tr)
@QtCore.pyqtSlot()
def zoom_out(self):
scale_tr = QtGui.QTransform()
scale_tr.scale(UiVentana.factor, UiVentana.factor)
scale_inverted, invertible = scale_tr.inverted()
if invertible:
tr = self._view.transform() * scale_inverted
self._view.setTransform(tr)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
更新:
如果您想分别使用+ 和- 进行放大和缩小,只需将快捷方式更改为:
QtWidgets.QShortcut(
QtGui.QKeySequence(QtCore.Qt.Key_Plus), # <---
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_in,
)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtCore.Qt.Key_Minus), # <---
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_out,
)
关于python - 放大和缩小小部件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57713795/