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:

  • UITextureButton

  • UIFlatButton

  • UISlider

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:

  1. owns a style property, which provides a mapping between a widgets state and style to be applied

  2. 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)