Container Screen

AbstractContainerScreen<T> is the base class for GUIs that interact with block entities or items (e.g., Chests, Furnaces, Backpacks). It extends the vanilla AbstractContainerScreen but implements IScreen.

The Coordinate System

Container screens differ from standard screens because they have a "Game Window" (usually 176x166 pixels) that floats in the center of the screen.

UI Lib provides two helper fields (inherited from vanilla) to help you position components relative to this window:

• leftPos: The absolute X coordinate of the left edge of the container window.
• topPos: The absolute Y coordinate of the top edge of the container window.

Setting the Size

In your constructor, you must define the size of your GUI texture so Minecraft can calculate leftPos and topPos correctly.

public class MyMachineScreen extends AbstractContainerScreen<MyMachineMenu> {
    public MyMachineScreen(MyMachineMenu menu, Inventory inventory, Component title) {
        super(menu, inventory, title);
        this.imageWidth = 176;
        this.imageHeight = 166;
    }
}

Adding Components

When adding components to a container screen, you almost always want them to move with the GUI window when the user resizes their game.

To do this, use leftPos and topPos in your init() method.

@Override
protected void init() {
    super.init(); // Calculates leftPos/topPos

    // Add a background sprite (The GUI texture)
    SpriteComponent bg = new SpriteComponent(
        leftPos, topPos, 
        imageWidth, imageHeight, 
        ResourceLocation.fromNamespaceAndPath("mymod", "container/machine_gui")
    );
    this.addComponent(bg);

    // Add a label relative to the GUI
    TextComponent label = new TextComponent(leftPos + 8, topPos + 6, this.title);
    this.addComponent(label);
}

Use Components for the GUI Background

In vanilla Minecraft, you usually override renderBg to draw your texture. In UI Lib, it is recommended to add a SpriteComponent (or AbstractSpriteComponent subclass) as the first component in init(). This treats the GUI background just like any other UI element.

Handling Slots & Tooltips

Vanilla AbstractContainerScreen handles the rendering of Item Slots and Item Tooltips automatically in super.render().

• Slots: Rendered after renderBg but before renderTooltip.
• Components: UI Lib renders components during the standard render phase.

Z-Index Considerations

If you add a SpriteComponent for your background, ensure it is added first. If you add it last, it might draw over the slots or items depending on the specific render phase hook.

renderBg

UI Lib leaves renderBg empty by default. If you prefer the vanilla way, you can still use it:

@Override
protected void renderBg(GuiGraphics guiGraphics, float partialTick, int mouseX, int mouseY) {
    // Vanilla style rendering
    int x = (width - imageWidth) / 2;
    int y = (height - imageHeight) / 2;
    guiGraphics.blit(TEXTURE, x, y, 0, 0, imageWidth, imageHeight);
}

Advanced: Dynamic Integration

Because AbstractContainerScreen implements IScreen, you can use all UI Lib features alongside your inventory:

1. Blurred Backgrounds: setBackground(new BlurredBackground()) works perfectly here to blur the world behind your inventory.
2. Validation Widgets: You can add EditBoxWidget to a container screen (e.g., for searching items) and use the validation API.
3. Skill Trees in Inventories: You can even embed a SkillTreeComponent inside a container screen tab.