ClassesMappingPreview

Introduction

Classes List Preview widget displays classes mapping. It can be used to display new names of classes that were edited by the user in the Classes Mapping widget for example.

Function signature

classes_mapping_preview = ClassesMappingPreview(
    classes=obj_classes,
    mapping=mapping,
    max_height="128px",
    widget_id=None,
)

default

Parameters

Parameters	Type	Description
classes	Union[List[ObjClass], ObjClassCollection]	Supervisely object class collection or list of object classes
mapping	Dict[str,str]	Dictionary where keys are class names and values are new names.
max_height	str	Text 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_preview = ClassesMappingPreview(
    classes=obj_classes
)

classes

mapping

Dictionary where keys are original class names and values are new names.

type: Dict[str,str]

default None

mapping = {obj_class.name: f"{obj_class.name}-detection" for obj_class in obj_classes}
classes_mapping_preview = ClassesMappingPreview(
    classes=obj_classes,
    mapping=mapping
)

mapping

max_height

Set the maximum height of the widget in pixels. If the content exceeds the maximum height, the scroll bar will appear.

type: str

default "128px"

classes_mapping_preview = ClassesMappingPreview(
    classes=obj_classes,
    max_height="100px"
)

widget_id

ID of the widget.

type: str

default value: None

Methods and attributes

Attributes and Methods	Description
set()	Set classes and mapping to widget.
set_mapping()	Set new mapping.
get_mapping()	Return current class mapping.
get_classes()	Return list of classes.

Mini App Example

In this example we will create a mini app with ClassesMappingPreview widget. We will create a ClassesMapping widget and display changed classes with ClassesMappingPreview widget.

You can find this example in our Github repository:

supervisely-ecosystem/ui-widgets-demos/media/016_classes_mapping_preview/src/main.py

Import libraries

import os
import supervisely as sly
from supervisely.app.widgets import (
    Card,
    Container,
    ClassesMapping,
    ClassesMappingPreview,
    Button,
    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 and init ClassesMapping widget

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,
]

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

Initialize ClassesMappingPreview widget and Button widget for saving and displaying mapping

classes_mapping_preview = ClassesMappingPreview()
save_button = Button("Save", button_size="mini")

Create app layout

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

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

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

Create app using layout

Create an app object with layout parameter.

app = sly.Application(layout=layout)

Add functions to control widgets from python code

@save_button.click
def save_mapping():
    mapping = classes_mapping.get_mapping()
    classes_mapping_preview.set(obj_classes, mapping)

mini-app-min