ClassesMapping

Introduction

Classes Mapping widget allows to rename given object classes with new names. It can be useful when you want to rename classes in your project.

Function signature

classes_mapping = ClassesMapping(
    classes=obj_classes,
    empty_notification=None,
    widget_id=None
)

Default with classes

Default with classes

Default without classes

Parameters

Parameters	Type	Description
classes	Union[List[ObjClass], ObjClassCollection]	Supervisely object class collection or list of object classes
empty_notification	NotificationBox	Notification that will be displayed when there are no classes in widget
widget_id	str	ID of the widget

classes

List of ObjClass objects or Supervisely object class collection (ObjClassCollection).

type: Union[List[ObjClass], ObjClassCollection]

classes_mapping = ClassesMapping(
    classes=obj_classes
)

empty_notification

Notification that will be displayed when there are no classes in the widget.

type: NotificationBox

default None

empty_notificaiton = NotificationBox(
    title="No classes", description="Provide classes to widget in order to map new names."
)
classes_mapping = ClassesMapping(
    classes=obj_classes,
    empty_notification=empty_notificaiton
)

custom-empty-text

widget_id

ID of the widget.

type: str

default value: None

Methods and attributes

Attributes and Methods	Description
set()	Set classes to widget.
get_classes()	Return list of all classes.
get_mapping()	Return edited classes mapping, if there were any changes.
ignore()	Ignore classes by indexes.
set_default()	Revert changes.
set_mapping()	Set new classes mapping.
select_all()	Select all classes.
deselect_all()	Deselect all classes.
select()	Select classes by ObjClass.
@selection_changed	Callback triggers when selection is changed.

Mini App Example

You can find this example in our Github repository:

supervisely-ecosystem/ui-widgets-demos/input/009_classes_mapping/src/main.py

Import libraries

import os
import supervisely as sly
from supervisely.app.widgets import Card, Container, ClassesMapping, Button, Text, NotificationBox
from dotenv import load_dotenv

Init API client

First, we load environment variables with credentials and init API for communicating with Supervisely Instance:

load_dotenv("local.env")
load_dotenv(os.path.expanduser("~/supervisely.env"))

api = sly.Api()

Create list of object classes

cat_obj_class = sly.ObjClass("cat", sly.Rectangle)
dog_obj_class = sly.ObjClass("dog", sly.Polygon)
horse_obj_class = sly.ObjClass("horse", sly.Bitmap)
cow_obj_class = sly.ObjClass("cow", sly.Polyline)
zebra_obj_class = sly.ObjClass("zebra", sly.Point)
obj_classes = [
    cat_obj_class,
    dog_obj_class,
    horse_obj_class,
    cow_obj_class,
    zebra_obj_class,
]

Initialize ClassesMapping widget, NotificationBox widget for custom notification

empty_notification = NotificationBox(
    title="No classes", description="Provide classes to widget in order to map new names."
)
classes_mapping = ClassesMapping(
    classes=obj_classes,
    empty_notification=empty_notification
)

Create Text widget for displaying changes and Button widget for saving changes

new_classes_names = Text(f"Press button to save changes", "info")
save_button = Button("Save", button_size="mini")

Create app layout

Prepare a layout for the app using the Card widget with the content parameter and place the widget that we've just created into the Container widget.

container = Container([classes_mapping, new_classes_names, save_button])

card = Card(
    title="Classes Mapping",
    content=container,
)
layout = Container(widgets=[card])

Create the app using the layout

Create an app object with the layout parameter.

app = sly.Application(layout=layout)

Add functions to control widgets from the python code

@save_button.click
def save_mapping():
    new_classes_names.hide()
    mapping = classes_mapping.get_mapping()
    new_class_names = []
    for obj_class in obj_classes:
        if obj_class.name in mapping:
            new_class_name = mapping[obj_class.name]["value"]
            if new_class_name != obj_class.name:
                new_class_names.append(new_class_name)
    if len(new_class_names) == 0:
        new_classes_names.set(f"No changes detected", "info")
    else:
        new_classes_names.set(f"New classes names: {','.join(new_class_names)}", "success")
    new_classes_names.show()

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