cardcanvas

CardCanvas is a library to create runtime-configurable dashboards using plotly dash. With a few class definitions, you can let your users build their dashboards and also analyze and present the data the way they want.

CardCanvas is built using plotly Dash. The UI is built using dash-mantine-components. The drag and drop is built using dash-snap-grid.

Installation

pip install cardcanvas

Here's a simple example code.

from cardcanvas import CardCanvas, Card
import dash_mantine_components as dmc

settings = {
    "title": "CardCanvas Demo",
    "subtitle": "A Demo application showing the capabilities of CardCanvas",
    "start_config": {},
    "logo": "https://img.icons8.com/?size=80&id=cjlQopC5NR3D&format=png",
    "grid_compact_type": "vertical",
    "grid_row_height": 100,
}


class TextCard(Card):
    title = "White text with a background color"
    description = "Testing out CardCanvas"
    icon = "mdi:file-document-edit"

    def render(self):
        return dmc.Card(
            dmc.Title(
                self.settings.get("text", "Hello CardCanvas"),
                c="white",
            ),
            bg=self.settings.get("color", "blue"),
            style={"height": "100%", "width": "100%"},
        )

    def render_settings(self):
        return dmc.Stack(
            [
                dmc.TextInput(
                    id={"type": "card-settings", "id": self.id, "setting": "text"},
                    value=self.settings.get("text", "Hello CardCanvas"),
                ),
                dmc.ColorPicker(
                    id={"type": "card-settings", "id": self.id, "setting": "color"},
                    value=self.settings.get("color", "grey"),
                ),
            ]
        )


canvas = CardCanvas(settings)
canvas.card_manager.register_card_class(TextCard)

canvas.app.run_server(debug=True)

Explanation

The CardCanvas class is a container class for a dash app. You can access the dash app instance using canvas.app. When initalizing the CardCanvas object, you can pass in a dictionary of settings. The various items you can configure is not documented yet, but look into the examples to get an idea. The plan is to add more configurable parts in the future.

A card manager manages the different Card classes. Each Card class is a blue print of how a configurable card looks like.

It should atleast have on method called render which will tell the app how to render that card. Optionally, you could add a render_settings method to set the configurable settings of the card. In the above example, you can set the text of the card and also the background color of the card. You have to be mindful of the id of the settings controls. They should follow the template {"type": "card-setting", "id": self.id, "setting": "<your unique setting name>"}

A limitation of the setting controls as of now is, they only support controls that sets the attribute value as the control's value. So for eg: you cannot use dmc.Checkbox which has it's value in the checked attribute. But you could use a CheckboxGroup instead.

It is upto you as a developer to decide which settings you want to expose for the user and use these settings in the render method. When the render method is called, you can access these settings using self.setting.

self.setting is a dictionary with the setting name as the key and value of the setting as the attribute. When the user updates the setting, the render method will be called and it can pick up the new values of the settings.

Card class

To create a new card type, you need to create a class inherit from cardcanvas.Card.

It should have few class attributes and also a render() method.

The following are the class attributes:

• title: The title of the card.
• description: A short description of the card.
• icon: The icon of the card. You can use the icons supported by Dash Iconify
• color: The color of the icon in card gallery. (default: "blue")

(The above attributes are used in the card gallery; for the user to drag and drop)

• interval: the interval at which the card will be re-rendered (in milliseconds). If not set, the card will not be auto-refreshed.
• debug: If true, the card will show the full traceback of errors (if any) in the card itself. (default: False)
• grid_settings: A dictionary with the following keys:
  • w: The width of the card in the grid.
  • h: The height of the card in the grid.
  • minW: The minimum width of the card in the grid.
  • minH: The minimum height of the card in the grid.
  • maxW: The maximum width of the card in the grid.
  • maxH: The maximum height of the card in the grid.
  • static (bool): If true, the card cannot be moved or resized. (default: False)
  • isDraggable (bool): If false, the card cannot be dragged. (default: True)
  • isResizable (bool): If false, the card cannot be resized. (default: True)
  • isBounded (bool): If true, the card will be bounded by the grid. (default: False)

Have a look at usage.py or the folder examples to see more examples.

The animation shown above can be found in examples/charts.py