Drawing shapes and images in libgdx dialog

Question

I am currently working on a dialog window for my android game using libgdx. This dialog window contains a collection of labels and buttons, but should also contain an image. The image represents the "remaining health indicator", i.e. an empty indicator with a symbol indicating the health of the player. This indicator has to be filled with a colored rectangle representing the remaining amount of health (see screenshot below).

In order to render this on a dialog of libgdx, I have to draw an image and a colored rectangle (the red rectangle indicating the real amount of remaining health). I know that the dialog supports the rendering of images, but I don't know how to first draw the rectangle.

This is the code I have so far:

public FuelFacilityDialog(GameWorld world, GuiComponent gui) { super("Health check", gui.defaultSkin);

    this.world = world;
    this.gui = gui;

    setModal(true);
    setMovable(false);
    setResizable(false);

    Image healthIndicator = new Image();
    Button button1   = new TextButton("heal", gui.defaultSkin);
    Button button4   = new TextButton("Exit", gui.defaultSkin);

    healthIndicator.setDrawable(new TextureRegionDrawable(AssetLoader.healthIndicatorV));
    healthIndicator.setScaling(Scaling.fit);
    setObject(button1, true);
    setObject(button4, false);

    Table imageTable = new Table();
    Table buttonTable = new Table();

    imageTable.add(healthIndicator).width(100).height(200);
    buttonTable.add(button1).width(100).height(50).expandY();

    this.getContentTable().padTop(20);
    this.getContentTable().padBottom(20);
    this.getContentTable().add(imageTable);
    this.getContentTable().add(buttonTable).height(200);
    getButtonTable().add(button2);
}

Answer 1

I have found the answer for my problem. In order to draw an image and a shape, one can use a pixmap. It is possible to first create a pixmap on which you draw a rectangle. Then, you create another pixmap on which you draw the image. Both pixmap then can be combined by drawing one pixmap onto the other.

This is the code I use to build an image containing a rectangle indicating the actual health level and drawing the indicator image on top of it.

private Image getHealthIndicatorImage() {
        Image indicatorImage = new Image();
        Pixmap healthIndicator = new Pixmap(AssetLoader.healthIndicatorV);
        Pixmap healthLevel = new Pixmap(healthIndicator.getWidth(), healthIndicator.getHeight(), Format.RGBA8888);

        healthLevel.setColor(Config.InstrumentPanel.healthInstrumentColor1);
        healthLevel.fillRectangle(0, 0, 50, 50);
        healthLevel.drawPixmap(healthIndicator, 0, 0);

        indicatorImage.setDrawable(new TextureRegionDrawable(new TextureRegion(new Texture(healthLevel))));
        indicatorImage.setScaling(Scaling.fit);

        return indicatorImage;
    }