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"""
This module contains a widget that can show the html preview of an
editor.
"""
from weakref import proxy
from pyqode.qt import QtCore, QtWidgets
from pyqode.core.api import DelayJobRunner
class HtmlPreviewWidget(QtWidgets.QTextEdit):
"""
Display html preview of a document as rich text in a QTextEdit.
"""
hide_requested = QtCore.Signal()
show_requested = QtCore.Signal()
def __init__(self, parent=None):
super(HtmlPreviewWidget, self).__init__(parent)
self._editor = None
self._timer = DelayJobRunner(delay=1000)
def set_editor(self, editor):
try:
self.setHtml(editor.to_html())
except (TypeError, AttributeError):
self.setHtml('<center>No preview available...</center>')
self._editor = None
self.hide_requested.emit()
else:
if self._editor is not None and editor != self._editor:
try:
self._editor.textChanged.disconnect(self._on_text_changed)
except TypeError:
pass
editor.textChanged.connect(self._on_text_changed)
self._editor = proxy(editor)
self.show_requested.emit()
def _on_text_changed(self, *_):
self._timer.request_job(self._update_preview)
def _update_preview(self):
try:
# remember cursor/scrollbar position
p = self.textCursor().position()
v = self.verticalScrollBar().value()
# display new html
self.setHtml(self._editor.to_html())
# restore cursor/scrollbar position
c = self.textCursor()
c.setPosition(p)
self.setTextCursor(c)
self.verticalScrollBar().setValue(v)
except (TypeError, AttributeError):
self.setHtml('<center>No preview available...</center>')
self.hide_requested.emit()
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