Nuke dockable panel example

menu.py

"""
This script shows how to create a dockable widget in Nuke using PySide2 based on a technique 
I used a long time ago in a project. 

I think nowadays I would reimplement something akin to nukescripts.panels.registerWidgetAsPanel 
that allows custom menu commands and single instances of the widget.
"""
import nuke
import nukescripts

from PySide2 import QtCore, QtGui, QtWidgets


def show_qt_pane(widget_class, title, pane_id):
    """
    Show a Qt widget in a Nuke panel.
    Parameters
    ----------
    widget_class: str
        Widget class to show in the panel. Needs to be the full path to the class, already imported.
        Example: "my_module.MyWidget"
    title: str
        Title of the panel.
    pane_id: str
        Unique identifier of the panel. Should match what is used when using registerWidgetAsPanel.
    """
    # Check if pane already exists.
    widgets = find_qt_widgets(pane_id)
    if widgets:
        # We found at least one instance, show the first one.
        widget = widgets[0]
        parent_widget = widgets[0].parentWidget()
        parent_widget.setCurrentWidget(widget)
        parent_widget.activateWindow()
        parent_widget.setFocus()
    else:
        # No instances were found, let's initialize a new one in a new Panel.
        panel = nukescripts.PythonPanel(title, pane_id)
        widget = nuke.PyCustom_Knob(title, "", "__import__('nukescripts').panels.WidgetKnob({})".format(widget_class))
        panel.addKnob(widget)
        panel.show()


def find_qt_widgets(widget_name):
    """
    Find a Qt widget in Nuke by its name.

    Parameters
    ----------
    widget_name: str

    Returns
    -------
    list[QtWidgets.QWidget]
    """
    qwindow = get_nuke_main_window()
    widgets = qwindow.findChildren(QtWidgets.QWidget, widget_name)
    return widgets


def get_nuke_main_window():
    """Returns Nuke's main window"""

    app = QtWidgets.QApplication.instance()
    for obj in app.topLevelWidgets():
        if obj.inherits('QMainWindow') and obj.metaObject().className() == 'Foundry::UI::DockMainWindow':
            return obj

    return None


# Make an example widget
class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super(MyWidget, self).__init__()
        layout = QtWidgets.QVBoxLayout()
        layout.setContentsMargins(0, 0, 0, 0)  # Nuke panels already have large margins, remove as much as possible
        self.setLayout(layout)
        self.label = QtWidgets.QLabel("Hello, World!")
        self.text_area = QtWidgets.QTextEdit()
        layout.addWidget(self.label)
        layout.addWidget(self.text_area)


def show_my_widget():
    show_qt_pane("MyWidget", "My Widget", "com.example.MyWidget")


if __name__ == '__main__':
    nukescripts.panels.registerWidgetAsPanel('MyWidget', 'This is my Widget', 'com.example.MyWidget')
    nuke.menu('Nuke').addCommand('Custom/Show My Widget', show_my_widget)