如何使标签文本轮廓化并适合标签的大小

Question

如何使标签文本被勾勒出来（以便在透明 Widget 上获得更好的可见性）并适合标签（根据函数 setWordWrap (True)？有一些示例说明如何做一个或另一个，但从不两者兼而有之。

透明小部件上的静态标签文本的基本示例是：

import sys

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


class Application(QWidget):
    def __init__(self):
        super().__init__()
        screen_size = QWidget.screen(self).size()
        screen_width = screen_size.width()
        screen_height = screen_size.height()
        widget_width = screen_width * 0.30


        self.setGeometry(100, 100, widget_width, screen_height)
        self.move(screen_width - widget_width, 0)
        self.setAttribute(Qt.WA_TransparentForMouseEvents)
        self.setWindowFlags(Qt.FramelessWindowHint | Qt.WindowStaysOnTopHint
                            | Qt.CustomizeWindowHint | Qt.Window)

        l1 = QLabel(self)
        l1.setWordWrap(True)
        l1.setGeometry(0, 0, widget_width, screen_height)
        l1.setFont(QFont('Arial', 22))
        l1.setStyleSheet('color:rgb(0,255,0)')
        l1.setText('Hello Hello Hello Hello Hello Hello Hello Hello Hello Hello Hello Hello')


def render_the_app():
    app = QApplication(sys.argv)
    window = Application()
    window.setAttribute(Qt.WA_TranslucentBackground)
    window.show()


    app.exec_()


render_the_app()

此代码示例将呈现绿色文本“Hello Hello ...”并呈现为： 在透明小部件上换行文本示例：

Answer 1

使用画家路径是一个很好的解决方案，但它不允许对内容进行更精细的控制，特别是考虑到基于文本的小部件还应该提供正确的大小提示，并且可能允许自动换行。

另一方面，QTextDocument 被任何使用文本的 QWidget 子类（有时公开，如 QTextEdit，其他内部，如 QLabel）提供大纲功能，因此可能的解决方案是创建一个类部分模仿 QLabel，提供正确的大小提示和自动换行。

class Test(QtWidgets.QWidget):
    _outlinePen = _alignment = None
    def __init__(self, text='', parent=None, **kwargs):
        super().__init__(parent)
        self.doc = QtGui.QTextDocument()
        self._reference = self.doc.clone()
        self.doc.contentsChanged.connect(self._rebuildReference)

        self._text = text
        self._outlineColor = QtGui.QColor(kwargs.get('outlineColor'))
        self._outlineWidth = kwargs.get('outlineWidth', 0)

        if text:
            self.doc.setPlainText(text)
            self.updateContents()

    def _rebuildReference(self):
        self._reference = self.doc.clone()

    def updateContents(self):
        cursor = QtGui.QTextCursor(self.doc)
        cursor.select(cursor.Document)
        blockFmt = cursor.blockFormat()
        blockFmt.setAlignment(self.alignment())
        cursor.setBlockFormat(blockFmt)
        charFmt = cursor.charFormat()
        charFmt.setFont(self.font())

        outlinePen = self.outlinePen()
        if outlinePen:
            charFmt.setTextOutline(outlinePen)

        cursor.setCharFormat(charFmt)
        self.updateGeometry()
        self.adjustSize()

    def text(self):
        return self._text

    def setText(self, text):
        if self._text == text:
            return
        self.doc.setPlainText(text)
        self.updateContents()

    def outlinePen(self):
        if isinstance(self._outlineColor, QtGui.QColor) and self._outlineColor.isValid():
            pen = QtGui.QPen(self._outlineColor)
            pen.setWidthF(self._outlineWidth or self.fontMetrics().lineWidth() * .25)
            return pen

    def setOutlinePen(self, pen):
        self._outlineColor = pen.brush().color()
        self._outlineWidth = pen.widthF()
        self.updateContents()

    def outlineColor(self):
        return self._outlineColor

    def setOutlineColor(self, color):
        if self._outlineColor != color:
            self._outlineColor = color
            self.updateContents()

    def outlineWidth(self):
        return self._outlineWidth

    def setOutlineWidth(self, width):
        if self._outlineWidth != width:
            self._outlineWidth = width
            self.updateContents()

    def alignment(self):
        alignment = self._alignment
        if not isinstance(alignment, (QtCore.Qt.Alignment, QtCore.Qt.AlignmentFlag)):
            alignment = QtCore.Qt.AlignTop
            if self.layoutDirection() == QtCore.Qt.LeftToRight:
                alignment |= QtCore.Qt.AlignLeft
            else:
                alignment |= QtCore.Qt.AlignRight
        return alignment

    def setAlignment(self, alignment):
        if self._alignment != alignment:
            self._alignment = alignment
            self.updateContents()

    def changeEvent(self, event):
        if event.type() == event.FontChange:
            self.updateContents()

    def sizeHint(self):
        if self.isVisible():
            doc = self._reference
            doc.setTextWidth(self.width())
        else:
            doc = self.doc
        return doc.size().toSize()

    def paintEvent(self, event):
        qp = QtGui.QPainter(self)
        self._reference.setTextWidth(self.width())
        self._reference.drawContents(qp, QtCore.QRectF(self.rect()))