JsonUI Java builder example

import static jsonui.layout.properties.Length.*; // px(), fr(), auto(), etc.

public class Example {
  public static void main(String[] args) {
    UIBuilder bd = new UIBuilder();
    UIScreen ui = bd
      .begWindow("PrimaryWindow")
        // Window child widget handling is different from panels
        // all widgets are positioned by coordinate
        .addChild(bd.builder(GridPanel.BUILDER)
          // Conventinally we put a widget that covers the whole window as the "root"
          .fillWindow()
          .columns(auto(), px(200))
          .rows(auto())
          .gridGap(px(4))
          .areas(
            "Editor", "Toolbox"
          )
          // Using custom widget implementation
          // #child(String, IWidget)
          .child("Editor", new CADEditor())
          // Using widget builder provided by lib
          // #child(String, WidgetBuilder)
          .child("Toolbox", bd.builder(StrictTablePanel.BUILDER)
            .growDirection(Side.DOWN)
            .overflowDirection(Side.RIGHT)
            .gap(px(4))
            // Native builder helper to execute a code block on stage
            // Stage.INIT executes the code right after build; note that the widget is invalid which means changing subtree is not allowed here
            // Stage.ATTACH executes the code after the widget became valid
            // Stage.INITIAL_ATTACH executes the code after the widget became valid; this is conventionally used for modifying subtree based on data
            // Stage.UPDATE executes the code on each clientTick
            // Stage.RENDER executes the code on each render call
            .exec(Stage.INITIAL_ATTACH, self -> {
              // 'self' is the widget
              for(ToolboxOption option : ToolboxOption.OPTIONS.values()) {
                self.child(option.getName(), option);
              }
            })
          )
        )
        // Window doesn't support length units (yet)
        .size(
          w -> (int) (screenWidth() * (2F / 3F)),
          w -> (int) (screenHeight() * (3F / 5F))
        )
        .position(
          w -> Alignment.xForCenter(screenWidth(), w.getWidth()),
          w -> Alignment.yForCenter(screenHeight(), w.getHeight())
        )
      .endWindow("PrimaryWindow")
      .start("PrimaryWindow")
      .allowJEI()
      .allowFTBCoreSidebarButtons()
      // Finishes building and return a GUI object
      .finish();
    Minecraft.getInstance().displayScreen(ui);
  }
}

public class CADEditor extends GridPanel<CADNode> {
  // ...
}