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 a state like ‘normal, ‘hover’ etc. to an instance of UIFlatButton.UIStyle.

Wellknown states¶

Name	Description
normal	The default state of a widget.
hover	Mouse hovered over an interactive widget.
press	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 own stylable widgets or extend existing ones.

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

owns a style property, which provides a mapping between a widgets state and style to be applied
provides an abstractmethod which have to provide a state (which is a simple string)

Tha basic idea:

a stylable widget has a state (e.g. ‘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)