GUI Style

Arcade 3.0 added a new approach for styling GUI widgets. It is flexible, yet also improves clarity and type safety.

Which Widgets Can I Style?

The following widgets support styling:

Basic Usage

This section will style a UIFlatButton as an example. You can use the same general approach for other stylable widgets, but you may want to check their documentation for additional values they may support.

To create your own widgets, please see the ‘Advanced’ section.

Quickstart

The following example shows how to adjust the style.

# Styles are dictionaries of UIStyle objects
new_style = {
    # You should provide a style for each widget state
    "normal": UIFlatButton.UIStyle(), # use default values for `normal` state
    "hover": UIFlatButton.UIStyle(
        font_color=arcade.color.BLACK,
        bg=arcade.color.WHITE,
    ),
    "press": UIFlatButton.UIStyle(
        font_color=arcade.color.BLACK,
        bg=arcade.color.WHITE,
        border=arcade.color.WHITE,
    ),
    "disabled": UIFlatButton.UIStyle(
        bg=arcade.color.GRAY,
    )
}

# Pass the style dictionary when creating a UI element
UIFlatButton(style=new_style)

Default style

Each stylable widget class has a DEFAULT_STYLE class attribute to hold the default style for that type of widget. For example, on UIFlatButton, you can access this attribute via UIFlatButton.DEFAULT_STYLE.

This default style will be used if no other style is provided when creating an instance of the class.

class UIFlatButton(UIInteractiveWidget, UIStyledWidget, UITextWidget):

    DEFAULT_STYLE = {
        "normal": UIStyle(),
        "hover": UIStyle(
            font_size=12,
            font_name=("calibri", "arial"),
            font_color=arcade.color.WHITE,
            bg=(21, 19, 21, 255),
            border=(77, 81, 87, 255),
            border_width=2,
        ),
        "press": UIStyle(
            font_size=12,
            font_name=("calibri", "arial"),
            font_color=arcade.color.BLACK,
            bg=arcade.color.WHITE,
            border=arcade.color.WHITE,
            border_width=2,
        ),
        "disabled": UIStyle(
            font_size=12,
            font_name=("calibri", "arial"),
            font_color=arcade.color.WHITE,
            bg=arcade.color.GRAY,
            border=None,
            border_width=2,
        )
    }

Style attributes

A UIStyle is a typed description of available style options. For the UIFlatButton the supported attributes are:

Name	Type	Default value	Description
`font_size`	`int`	12	Size of the text on the button
`font_name`	`FontNameOrNames`	`("calibri", "arial")`	Font of the text
`font_color`	`RGBA255`	`arcade.color.WHITE`	Color of text
`bg`	`RGBA255`	`(21, 19, 21, 255)`	Background color
`border`	`Optional`	`None`	Border color
`border_width`	`int`	0	Border width

The style attribute is a dictionary, which maps states such as normal, hover, press, and disabled to an instance of the class’s UIStyle.

Common states

Name	Description
`normal`	The default state of a widget.
`hover`	The mouse is hovered over an interactive widget.
`press`	The mouse is pressed while hovering over the widget.
`disabled`	The widget is disabled.

Advanced

This section describes the styling system itself, and how it can be used to create your own stylable widgets or extend existing ones.

Stylable widgets inherit from UIStyledWidget(), which provides two basic features:

A style property, which provides a mapping between a widget’s state and style to be applied.
Provides an abstractmethod to provide a state, which is a simple string.

Tha basic idea:

A stylable widget has a state, which can be normal, hover, press, or disabled.
The state is used to define which style will be applied.

Your own stylable widget

class MyColorBox(UIStyledWidget, UIInteractiveWidget, UIWidget):
    """
    A colored box, which changes on mouse interaction
    """

    # create the style class, which will be used to define style for any widget state
    @dataclass
    class UIStyle(UIStyleBase):
        color: RGBA255 = arcade.color.GREEN

    DEFAULT_STYLE = {
        "normal": UIStyle(),
        "hover": UIStyle(color=arcade.color.YELLOW),
        "press": UIStyle(color=arcade.color.RED),
        "disabled": UIStyle(color=arcade.color.GRAY)
    }

    def get_current_state(self) -> str:
        """Returns the current state of the widget i.e.disabled, press, hover or normal."""
        if self.disabled:
            return "disabled"
        elif self.pressed:
            return "press"
        elif self.hovered:
            return "hover"
        else:
            return "normal"

    def do_render(self, surface: Surface):
        self.prepare_render(surface)

        # get current style
        style: MyColorBox.UIStyle = self.get_current_style()

        # Get color from current style, it is a good habit to be
        # bullet proven for missing values in case a dict is provided instead of a UIStyle
        color = style.get("color", MyColorBox.UIStyle.bg)

        # render
        if color: # support for not setting a color at all
            surface.clear(bg_color)