QtGui.q油漆工覆盖在QtGui.QTextEdi

Question

我创建了一个小的文本编辑器，用户可以通过将鼠标悬停在文本块上并旋转鼠标滚轮来增加字体大小。到目前为止，这部分工作正常。 我的问题是可视化字体大小的变化。在

我想在鼠标位置画一个圆并显示当前的字体大小。到目前为止，我不确定如何在QTextEdit上覆盖（文本仍然可读）。在

我收到一个“QPainter:：begin:Widget painting can begin as a result a paintEvent”错误。在

import sys
from PyQt4 import QtGui, QtCore
import re
from itertools import chain

class Painter(QtGui.QWidget):
    def __init__(self, parent=None):
        super(Painter, self).__init__(parent)
        self.paintEvent()
        #the line above probably triggers the error

    def paintEvent(self):
        qp = QtGui.QPainter(self)
        self.drawCircle(qp)
        self.drawText(qp)

    def drawText(self, qp):
        qp.setPen(QtGui.QColor(0, 0, 0))
        qp.setFont(QtGui.QFont('Decorative', 32))
        st = SuperText()
        x = st.mouseX - 55
        y = st.mouseY + 16
        qp.drawText(x, y, "TEST")

    def drawCircle(self, qp):
        st = SuperText()
        x = st.mouseX
        y = st.mouseY
        qp.setBrush(QtGui.QColor(0, 0, 255))
        self.center = QtCore.QPoint(x, y)
        qp.drawEllipse(self.center, 80, 80)


class SuperText(QtGui.QTextEdit):

    def __init__(self):
        super(SuperText, self).__init__()
        #....

    def initUI(self):
        self.setGeometry(0, 0, 640, 480)
        self.setWindowTitle('SuperText')
        self.setFocusPolicy(QtCore.Qt.StrongFocus)
        self.setMouseTracking(True)
        self.show()

    def wheelEvent(self, ev):
        super(SuperText, self).wheelEvent(ev)
        self.generateTemplate()
        self.renderTemplate()
        self.mouseX = ev.x()
        self.mouseY = ev.y()
        anc = self.anchorAt(ev.pos())
        if (anc):
            self.changeSize(anc, ev.delta())
            painter = Painter(self)
            painter.update()

    def onTextChanged(self):
        # update text when user inputs text
        self.text = self.toPlainText()
        self.readText()

def readText(self):
    data = self.text
    # split textfile at linebreak
    self.paragraphs = data.split("\n")
    for i in range(len(self.paragraphs)):
        # set standard size for each paragraph
        self.sizes.append(14)

def generateTemplate(self):
    p = self.paragraphs
    content = "".join(str(i) for i in chain(*p))
    if len(p) == 0:
        self.template = p
        return
    for i in range(len(p)):
        size = str(self.sizes[i])
        content = re.sub(str(p[i]),
                         "<a class='paragraph' href='%d' style='color:#000; text-decoration:none;'><p style='font-size:%spx'>$%d$</p></a>" % (i, size, i),
                         content, count=1)
    content = content + "<style>a:hover { background: #f00; }</style>"
    self.template = content

def renderTemplate(self):
    cur = self.textCursor()
    doc = self.template
    for i, paragraph in enumerate(self.paragraphs):
        doc = doc.replace('$' + str(i) + '$', '%s' % (paragraph))
    self.setHtml(doc)
    self.setTextCursor(cur)

def changeSize(self, paragraphId, amount):
    i = int(paragraphId)
    size = self.sizes[i]
    newSize = self.sizes[i] + (amount / 120)
    self.sizes[i] = newSize
    htmlCheck = self.toHtml()
    self.generateTemplate()
    self.renderTemplate()


def main():
    app = QtGui.QApplication(sys.argv)
    super_text = SuperText()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

有人能解释一下我做错了什么，或者给我指出正确的方向吗？在

Answer 1

我删除了Painter类，并将它的代码放在SuperText类中；编辑paintEvent（）和wheelEvent（）的结果是：

def paintEvent(self, event):
    qp = QtGui.QPainter()
    qp.begin(self.viewport())
    self.drawCircle(qp)
    self.drawText(qp)
    qp.end()
    super(SuperText, self).paintEvent(event)
    #the last line ensures the visiblity of the QTextedit

以及

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