gradio/components/html.py

"""gr.HTML() component."""

from __future__ import annotations

from collections.abc import Callable, Sequence
from typing import TYPE_CHECKING, Any

from gradio_client.documentation import document

from gradio.components.base import Component
from gradio.events import Events

if TYPE_CHECKING:
    from gradio.components import Timer


@document()
class HTML(Component):
    """
    Creates a component to display arbitrary HTML output. As this component does not accept user input, it is rarely used as an input component.

    Demos: blocks_scroll
    Guides: key-features
    """

    EVENTS = [Events.change]

    def __init__(
        self,
        value: str | Callable | None = None,
        *,
        label: str | None = None,
        every: Timer | float | None = None,
        inputs: Component | Sequence[Component] | set[Component] | None = None,
        show_label: bool = False,
        visible: bool = True,
        elem_id: str | None = None,
        elem_classes: list[str] | str | None = None,
        render: bool = True,
        key: int | str | None = None,
        min_height: int | None = None,
        max_height: int | None = None,
    ):
        """
        Parameters:
            value: Default value. If callable, the function will be called whenever the app loads to set the initial value of the component.
            label: the label for this component. Is used as the header if there are a table of examples for this component. If None and used in a `gr.Interface`, the label will be the name of the parameter this component is assigned to.
            every: Continously calls `value` to recalculate it if `value` is a function (has no effect otherwise). Can provide a Timer whose tick resets `value`, or a float that provides the regular interval for the reset Timer.
            inputs: Components that are used as inputs to calculate `value` if `value` is a function (has no effect otherwise). `value` is recalculated any time the inputs change.
            show_label: If True, the label will be displayed. If False, the label will be hidden.
            visible: If False, component will be hidden.
            elem_id: An optional string that is assigned as the id of this component in the HTML DOM. Can be used for targeting CSS styles.
            elem_classes: An optional list of strings that are assigned as the classes of this component in the HTML DOM. Can be used for targeting CSS styles.
            render: If False, component will not render be rendered in the Blocks context. Should be used if the intention is to assign event listeners now but render the component later.
            key: if assigned, will be used to assume identity across a re-render. Components that have the same key across a re-render will have their value preserved.
            min_height: The minimum height of the component, specified in pixels if a number is passed, or in CSS units if a string is passed. If HTML content exceeds the height, the component will expand to fit the content.
            max_height: The maximum height of the component, specified in pixels if a number is passed, or in CSS units if a string is passed. If content exceeds the height, the component will scroll.
        """
        self.min_height = min_height
        self.max_height = max_height
        super().__init__(
            label=label,
            every=every,
            inputs=inputs,
            show_label=show_label,
            visible=visible,
            elem_id=elem_id,
            elem_classes=elem_classes,
            render=render,
            key=key,
            value=value,
        )

    def example_payload(self) -> Any:
        return "<p>Hello</p>"

    def example_value(self) -> Any:
        return "<p>Hello</p>"

    def preprocess(self, payload: str | None) -> str | None:
        """
        Parameters:
            payload: string corresponding to the HTML
        Returns:
            (Rarely used) passes the HTML as a `str`.
        """
        return payload

    def postprocess(self, value: str | None) -> str | None:
        """
        Parameters:
            value: Expects a `str` consisting of valid HTML.
        Returns:
            Returns the HTML string.
        """
        return value

    def api_info(self) -> dict[str, Any]:
        return {"type": "string"}