ali-rs / lemur-themer

Lemur-Themer

A Theming library allowing the creation, loading and saving of themes for Lemur.

Themes are saved in JSON format.

Using the Themer

Themes are loaded using the setTheme(String) or setTheme(File) methods. Themes are saved using the saveActiveTheme() method. If the theme does not exist one will be created and populated by the default glass theme.

public class TestThemeLoading extends SimpleApplication {

    public static void main(String... args) {

        TestThemeLoading testThemeLoading = new TestThemeLoading();

        AppSettings appSettings = new AppSettings(true);
        appSettings.setResolution(800, 600);

        testThemeLoading.setSettings(appSettings);
        testThemeLoading.setShowSettings(false);
        testThemeLoading.start();

    }

    private TestThemeLoading() {
        super (new AppState[0]);
    }

    @Override
    public void simpleInitApp() {

        GuiGlobals.initialize(this);

        LemurThemer lemurThemer = new LemurThemer();
        lemurThemer.setTheme("./mytheme.lemur.json");

        Container container = new Container();
        container.addChild(new Label("I am a themed label."));
        container.addChild(new Button("I am a themed button"));
        container.addChild(new Checkbox("I am a themed checkbox"));

        container.setLocalTranslation(new Vector3f(
                cam.getWidth() * 0.5f - container.getPreferredSize().x * 0.5f,
                cam.getHeight() * 0.5f + container.getPreferredSize().y * 0.5f,
                1.0f));

        guiNode.attachChild(container);

    }

}

Extending Themes

Users that have created custom GUI elements can also have them themed. To theme a custom element create a class that extends ThemedElement. If your element extends an existing element, extend that ThemedElement too. For example if your element extends Label then your ThemedElement should extend LabelTheme. This will give it all of the properties of the label theme in addition to your custom properties. Below is an example of the built-in ButtonTheme that extends LabelTheme.

public class ButtonTheme extends LabelTheme {

    private ColorRGBA color = new ColorRGBA(0.8f, 0.9f, 1.0f, 0.85f);
    private ColorRGBA focusColor = ColorRGBA.Green.clone();
    private ColorRGBA highlightColor = ColorRGBA.Yellow.clone();

    @JsonTypeInfo( use = JsonTypeInfo.Id.CLASS)
    private GuiComponent background = BackgroundComponents.gradient(new ColorRGBA(0.0f, 0.75f, 0.75f, 0.5f));

    private Insets3f insets = new Insets3f(2, 2, 2, 2);

    // The ElementId this class will be applying the theme to.
    public ButtonTheme() {
        super("button");
    }

    public ButtonTheme(String elementId) {
        super(elementId);
    }

}

Field names are consistent with the attribute name you are applying. For example, the field color will apply the attribute "color" to the element "button" with the value of the color field. This is equivalent to:

attributes = styles.getSelector("button", "glass");
attributes.set("color", color);
attributes.set("focusColor", focusColor);
attributes.set("highlightColor", highlightColor)

Polymorphic fields

For polymorphic fields the JSON parser needs to understand which class to construct. To advise the JSON parser we add an Annotation to the field. The annotation is instructing the JSON parser to create and read a field called "@class" to store the fully-qualified class name.

@JsonTypeInfo( use = JsonTypeInfo.Id.CLASS)

Theme Packages

Lemur-Themer scans for classes that extend ThemedElement and applies the theme automatically. Scanning the entire classpath can take a considerable amount of time in large projects or low-power devices such as a mobile device or raspberry Pi. To alleviate this issue the user must place their theme classes in the com.jayfella.lemur.theme package.