Convert QtWidgets into a Magic Widget

If your are an experienced GUI developper, you may often want to define your own Qt widget classes. Still, it is a good idea to convert it into a magicgui's widget in terms of API consistency and simplicity. Especially if you intend to make your GUI accessible via Python interpreter, hiding huge number of methods defined in QWidget class is very important for code completion and safety.

The easiest way to do that in magicclass is to inherit FreeWidget. It is aimed at constructing a magicgui.widgets.Widget object with custom Qt widget. Actually, many widgets in magicclass.widgets are defined in this way.

Basic Usage

Suppose you have a Qt widget defined like:

from qtpy.QtWidgets import QWidget

class MyQWidget(QWidget):
    ...

To convert it into a magicgui's widget, you'll have to call set_widget method after initializing the super class.

from magicclass.widgets import FreeWidget

class MyWidget(FreeWidget):
    def __init__(self):
        super().__init__()  # initialize
        self.wdt = MyQWidget()  # construct Qt widget
        self.set_widget(self.wdt)  # set widget

Now the MyQWidget object is correctly imported into magicgui.widgets.Widget and is ready to used as if it is an ordinary magicgui's widget.

x = MyWidget()

# properties and methods inherited from "Widget"
x.visible = False
x.enabled = True
x.show()
x.hide()

# append into a container
from magicgui.widgets import Container
container = Container()
container.append(x)

Make It Behave More Like A ValueWidget

magicgui.widgets.ValueWidget is widgets that have representative values. You'll have to define value property to make a FreeWidget more like a ValueWidget. It is better idea to add a value change signal to the class.

Following example shows how to define value getter/setter and value change signal, suppose the MyQWidget has methods value, setValue and the corresponding signal valueChanged.

from psygnal import Signal

class MyWidget(FreeWidget):
    # you should restrict the type of signal emission according to the Qt widget,
    # such as Signal(str)
    changed = Signal(object)

    def __init__(self):
        super().__init__()  # initialize
        self.wdt = MyQWidget()  # construct Qt widget
        self.wdt.valueChanged.connect(self.changed.emit)  # relay signal
        self.set_widget(self.wdt)  # set widget

    @property
    def value(self):
        return self.wdt.value()

    @value.setter
    def value(self, v):
        self.wdt.setValue(v)