embed-win-qte2.py

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit, QWidget, QVBoxLayout, QLabel, QTextBrowser
from PyQt5.QtGui import QTextCursor, QTextCharFormat, QFont, QTextImageFormat, QTextObjectInterface, QPainter, QTextFormat, QWindow
from PyQt5.QtCore import QSize, QSizeF, QObject, QPoint
from subprocess import Popen, PIPE, STDOUT

class EmbeddedWinFormat(QObject, QTextObjectInterface):
    def __init__(self, text_edit, widget):
        super().__init__()
        self.text_edit = text_edit
        self.widget = widget

    def _sizeHint(self):
        width = self.text_edit.width()
        return QSize(width, max(100, self.widget.height()))

    def drawObject(self, painter, rect, doc, posInDocument, format):
        self.widget.resize(self._sizeHint())
        self.widget.render(painter, QPoint(int(rect.x()), int(rect.y())))
        self.widget.move(int(rect.x()) + 1, int(rect.y()) + 1)

    def intrinsicSize(self, doc, posInDocument, format):
        return QSizeF(self._sizeHint())

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        self.counter = QTextFormat.UserObject + 1

        self.setWindowTitle("QTextEdit Widget Embedding Example")
        self.setMinimumSize(1024, 768)

        self.text_edit = QTextEdit()
        self.setCentralWidget(self.text_edit)

        self.text_edit.append("Embedded widget")
        win_id = self.start_client()
        self.embed_widget_into_text_edit(self._embed_window(win_id))
        self.text_edit.append("\nNext line")

    def start_client(self):
        p = Popen(['python3', '-u', 'test-window.py'], stdout=PIPE, stderr=STDOUT, text=True)
        win_id = int(p.stdout.readline().split()[-1].strip())
        self.destroyed.connect(lambda *_: p.kill())
        return win_id

    def _embed_window(self, win_id):
        external_window = QWindow.fromWinId(win_id)
        external_window.show()
        return QWidget.createWindowContainer(external_window, self.text_edit)

    def embed_widget_into_text_edit(self, widget):
        cursor = self.text_edit.textCursor()
        cursor.movePosition(QTextCursor.End)

        self.counter += 1
        fmt_id = self.counter

        self.text_edit.document().documentLayout().registerHandler(
            fmt_id,
            EmbeddedWinFormat(self.text_edit, widget)
        )

        cursor.insertBlock()
        widget_format = QTextCharFormat()
        widget_format.setObjectType(fmt_id)
        cursor.insertText(chr(0xfffc), widget_format)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())