components/button.py

"""gr.Button() component."""

from __future__ import annotations

from typing import Any, Callable, Literal

from gradio_client.documentation import document

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


@document()
class Button(Component):
    """
    Creates a button that can be assigned arbitrary .click() events. The value (label) of the button can be used as an input to the function (rarely used) or set via the output of a function.
    """

    EVENTS = [Events.click]

    def __init__(
        self,
        value: str | Callable = "Run",
        *,
        every: float | None = None,
        variant: Literal["primary", "secondary", "stop"] = "secondary",
        size: Literal["sm", "lg"] | None = None,
        icon: str | None = None,
        link: str | None = None,
        visible: bool = True,
        interactive: bool = True,
        elem_id: str | None = None,
        elem_classes: list[str] | str | None = None,
        render: bool = True,
        key: int | str | None = None,
        scale: int | None = None,
        min_width: int | None = None,
    ):
        """
        Parameters:
            value: Default text for the button to display. If callable, the function will be called whenever the app loads to set the initial value of the component.
            every: If `value` is a callable, run the function 'every' number of seconds while the client connection is open. Has no effect otherwise. The event can be accessed (e.g. to cancel it) via this component's .load_event attribute.
            variant: 'primary' for main call-to-action, 'secondary' for a more subdued style, 'stop' for a stop button.
            size: Size of the button. Can be "sm" or "lg".
            icon: URL or path to the icon file to display within the button. If None, no icon will be displayed.
            link: URL to open when the button is clicked. If None, no link will be used.
            visible: If False, component will be hidden.
            interactive: If False, the Button will be in a disabled state.
            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.
            scale: relative size compared to adjacent Components. For example if Components A and B are in a Row, and A has scale=2, and B has scale=1, A will be twice as wide as B. Should be an integer. scale applies in Rows, and to top-level Components in Blocks where fill_height=True.
            min_width: minimum pixel width, will wrap if not sufficient screen space to satisfy this value. If a certain scale value results in this Component being narrower than min_width, the min_width parameter will be respected first.
        """
        super().__init__(
            every=every,
            visible=visible,
            elem_id=elem_id,
            elem_classes=elem_classes,
            render=render,
            key=key,
            value=value,
            interactive=interactive,
            scale=scale,
            min_width=min_width,
        )
        self.icon = self.serve_static_file(icon)
        self.variant = variant
        self.size = size
        self.link = link

    @property
    def skip_api(self):
        return True

    def preprocess(self, payload: str | None) -> str | None:
        """
        Parameters:
            payload: string corresponding to the button label
        Returns:
            (Rarely used) the `str` corresponding to the button label when the button is clicked
        """
        return payload

    def postprocess(self, value: str | None) -> str | None:
        """
        Parameters:
            value: string corresponding to the button label
        Returns:
            Expects a `str` value that is set as the button label
        """
        return str(value)

    def example_payload(self) -> Any:
        return "Run"

    def example_value(self) -> Any:
        return "Run"