material

Overview ¶

Package material implements the Material design.

To maximize reusability and visual flexibility, user interface controls are split into two parts: the stateful widget and the stateless drawing of it.

For example, widget.Button encapsulates the state and event handling of all buttons, while the Theme can draw a single Button in various styles.

This snippet defines a button that prints a message when clicked:

var gtx *layout.Context
button := new(widget.Button)

for button.Clicked(gtx) {
    fmt.Println("Clicked!")
}

Use a Theme to draw the button:

theme := material.NewTheme(...)

th.Button("Click me!").Layout(gtx, button)

Customization ¶

Quite often, a program needs to customize the theme provided defaults. Several options are available, depending on the nature of the change:

Mandatory parameters: Some parameters are not part of the widget state but have no obvious default. In the program above, the button text is a parameter to the Theme.Button method.

Theme-global parameters: For changing the look of all widgets drawn with a particular theme, adjust the `Theme` fields:

theme.Color.Primary = color.RGBA{...}

Widget-local parameters: For changing the look of a particular widget, adjust the widget specific theme object:

btn := th.Button("Click me!")
btn.Font.Style = text.Italic
btn.Layout(gtx)

Widget variants: A widget can have several distinct representations even though the underlying state is the same. A widget.Button can be drawn as a round icon button:

icon := material.NewIcon(...)

th.IconButton(icon).Layout(gtx, button)

Specialized widgets: Theme both define a generic Label method that takes a text size, and specialized methods for standard text sizes such as Theme.H1 and Theme.Body2.