ku_labeler tweaks - http://www.nukepedia.com/python/nodegraph/ku_labler

ku_labeler.py

# Source: http://www.nukepedia.com/python/nodegraph/ku_labler
# Tweaks to make it work with multiline by Erwan Leroy

import nuke
from Qt import QtWidgets, QtGui, QtCore


class Core_SetLabel(QtWidgets.QDialog):
    def __init__(self):
        super(Core_SetLabel,self).__init__()
        self.nodes = []

        self.text_edit = QtWidgets.QTextEdit()
        self.text_edit.setAlignment(QtCore.Qt.AlignCenter)
        self.title = QtWidgets.QLabel("<b>Set Label</b>")
        self.title.setAlignment(QtCore.Qt.AlignHCenter)

        self.help = QtWidgets.QLabel('<span style=" font-size:7pt; color:green;">Ctrl+Enter to confirm</span>')
        self.help.setAlignment(QtCore.Qt.AlignRight)

        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.title)
        self.layout.addWidget(self.text_edit)
        self.layout.addWidget(self.help)
        self.setLayout(self.layout)
        self.resize(200,200)
        self.setWindowTitle("Set Label")
        self.setWindowFlags(QtCore.Qt.FramelessWindowHint | QtCore.Qt.WindowStaysOnTopHint | QtCore.Qt.Popup)

        self.text_edit.installEventFilter(self)


    def eventFilter(self, widget, event):
        if isinstance(event, QtGui.QKeyEvent):
            if event.key() == QtCore.Qt.Key_Return and  event.modifiers() == QtCore.Qt.ControlModifier:
                '''change label with enter-key is pressed'''
                newLabel = self.text_edit.toPlainText()
                for n in self.nodes:
                    n['label'].setValue(newLabel)
                self.close()
                self.nodes = []
                return True
        return False


    def getNodes(self, dag):
        '''get the existing label of selected nodes'''
        print dag
        if dag == "Node Graph":
            context = nuke.root()
        else:
            context = nuke.toNode('root.' + dag.replace(" Node Graph", ""))
            if not context:
                return False
        with context:
            self.nodes = nuke.selectedNodes()
            if self.nodes:
                self.title.setText("<b>Set Label</b>")
                self.text_edit.setText(self.nodes[0]['label'].value())
                return True
        return False

    def run(self):
        '''rerun instance'''
        cursor = QtGui.QCursor.pos()
        try:
            dag = QtWidgets.QApplication.instance().widgetAt(cursor).parent().windowTitle()
        except:  # TODO: Figure out what kind of error could happen
            return
        if self.getNodes(dag):
            avail_space = QtWidgets.QDesktopWidget().availableGeometry(cursor)
            # QDesktopWidget will be deprecated in a later version of QT, use the following line instead
            # avail_space = QtWidgets.QApplication.instance().screenAt(QtGui.QCursor.pos()).availableGeometry()
            posx = min(max(cursor.x()-100, avail_space.left()), avail_space.right()-200)
            posy = min(max(cursor.y()-12, avail_space.top()), avail_space.bottom()-200)
            self.move(QtCore.QPoint(posx, posy))
            self.raise_()
            self.text_edit.setFocus()
            self.text_edit.selectAll()
            self.show()


LABELPOPUP = Core_SetLabel()


# Add to Menu/Edit

m_tab = nuke.menu("Nuke").findItem("Edit")
m_tab.addCommand("ku_labeler", LABELPOPUP.run, 'shift+n', shortcutContext=2)