Question

我想知道如何根据它的最大宽度/高度来最好地截断QLabel中的文本。传入的文本可以是任意长度，但为了保持整洁的布局，我想截断长字符串以填充最大空间（小部件的最大宽度/高度）。

E.g：

 'A very long string where there should only be a short one, but I can't control input to the widget as it's a user given value'

会变成：

'A very long string where there should only be a short one, but ...'

基于当前字体所需的空间。

我怎样才能做到最好？

这是我所追求的一个简单示例，尽管这是基于字数，而不是可用空间：

import sys
from PySide.QtGui import *
from PySide.QtCore import *


def truncateText(text):
    maxWords = 10
    words = text.split(' ')
    return ' '.join(words[:maxWords]) + ' ...'

app = QApplication(sys.argv)

mainWindow = QWidget()
layout = QHBoxLayout()
mainWindow.setLayout(layout)

text = 'this is a very long string, '*10
label = QLabel(truncateText(text))
label.setWordWrap(True)
label.setFixedWidth(200)
layout.addWidget(label)

mainWindow.show()
sys.exit(app.exec_())

Answer 1

更简单 - 使用QFontMetrics.elidedText方法并重载paintEvent，这是一个例子：

from PyQt4.QtCore import Qt
from PyQt4.QtGui import QApplication,\
                        QLabel,\
                        QFontMetrics,\
                        QPainter

class MyLabel(QLabel):
    def paintEvent( self, event ):
        painter = QPainter(self)

        metrics = QFontMetrics(self.font())
        elided  = metrics.elidedText(self.text(), Qt.ElideRight, self.width())

        painter.drawText(self.rect(), self.alignment(), elided)

if ( __name__ == '__main__' ):
    app = None
    if ( not QApplication.instance() ):
        app = QApplication([])

    label = MyLabel()
    label.setText('This is a really, long and poorly formatted runon sentence used to illustrate a point')
    label.setWindowFlags(Qt.Dialog)
    label.show()

    if ( app ):
        app.exec_()

Answer 2

我发现@Eric Hulser 的回答虽然很棒，但在将标签放入另一个小部件时不起作用。

我通过将 Eric 的响应和 Qt Elided Label Example 混在一起来想出这个。如此处所述，它允许传入不同的省略模式并垂直保留文本（当然是水平省略！）。

实施 according to the docs 的布局阶段我不清楚，所以我不能很好地谈论它。基本上，它会检查标签文本是否超出标签的宽度；如果是，它会忽略文本。

a "valid" line 的含义也不清楚。删除这些检查会导致应用程序崩溃。我的猜测是当它不超出小部件时该行是有效的。

如果你想使用 PySide，

PyQt5 -> PySide2
pyqtSignal -> 信号

无论如何，享受吧！

import sys
from PyQt5 import QtCore, QtWidgets, QtGui


class EliderLabel(QtWidgets.QLabel):

    elision_changed = QtCore.pyqtSignal(bool)

    def __init__(self, text='', mode=QtCore.Qt.ElideRight, **kwargs):
        super().__init__(**kwargs)

        self._mode = mode
        self.elided = False

        self.setSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        self.setText(text)

    def setText(self, text):
        self._contents = text
        # Changing the content require a repaint of the widget (or so
        # says the overview)
        self.update()

    def text(self):
        return self._contents

    def minimumSizeHint(self):
        metrics = QtGui.QFontMetrics(self.font())
        return QtCore.QSize(0, metrics.height())

    def paintEvent(self, event):

        super().paintEvent(event)

        did_elide = False

        painter = QtGui.QPainter(self)
        font_metrics = painter.fontMetrics()
        # fontMetrics.width() is deprecated; use horizontalAdvance
        text_width = font_metrics.horizontalAdvance(self.text())

        # Layout phase, per the docs
        text_layout = QtGui.QTextLayout(self._contents, painter.font())
        text_layout.beginLayout()

        while True:

            line = text_layout.createLine()

            if not line.isValid():
                break

            line.setLineWidth(self.width())

            if text_width >= self.width():
                elided_line = font_metrics.elidedText(self._contents, self._mode, self.width())
                painter.drawText(QtCore.QPoint(0, font_metrics.ascent()), elided_line)
                did_elide = line.isValid()
                break
            else:
                line.draw(painter, QtCore.QPoint(0, 0))

        text_layout.endLayout()

        self.elision_changed.emit(did_elide)

        if did_elide != self.elided:
            self.elided = did_elide
            self.elision_changed.emit(did_elide)


class MyDialog(QtWidgets.QWidget):

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

        text = 'This is a really, long and poorly formatted runon sentence used to illustrate a point'
        label = EliderLabel(text, parent=self)

        label.elision_changed.connect(self.on_elide)

        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(label)

        self.setLayout(layout)

    def on_elide(self, val):
        print('Elided: ', val, flush=True)


if __name__ == '__main__':
    app = QtWidgets.QApplication([])
    dia = MyDialog()
    dia.show()

    sys.exit(app.exec_())

Answer 3

您可以通过QFontMetrics确定宽度来实现此目的，请参阅this answer。

您可能想要使用或创建一些能够快速找到切割位置的算法，除非在简单的for循环中完成它就足够了。

PySide / PyQt基于minimumSize截断QLabel中的文本

3 个答案: