Refactor DiceOS architecture: introduce DiceOSAdapter, enhance event handling in Component, and improve window management

GEMINI.md

@@ -15,7 +15,7 @@ The project uses Gradle.
 *   **Language:** Java
 *   **Dependency Injection:** Uses `avaje-inject`. Components are marked with `@Component` and injected via constructor.
 *   **Boilerplate:** Uses `lombok` for boilerplate reduction.
-*   **Rendering:** Built on LibGDX. Main entry point is `DiceOS.java` which extends `ApplicationAdapter`.
+*   **Rendering:** Built on LibGDX. Main entry point is `DiceOSAdapter.java` which extends `ApplicationAdapter`.
 *   **Asset Loading:** All assets, including textures, fonts, and NinePatches, must be loaded via the `ResourceLoader` service to ensure proper lifecycle management and caching.
 *   **Project Structure:**
     *   `src/main/java/be/seeseemelk/diceos/system`: Core OS services (Display, Window, Input, etc.).

src/main/java/be/seeseemelk/diceos/Bootloader.java

@@ -1,6 +1,7 @@
 package be.seeseemelk.diceos;
 
 import be.seeseemelk.diceos.system.DiceOS;
+import be.seeseemelk.diceos.system.DiceOSAdapter;
 import com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application;
 import com.badlogic.gdx.backends.lwjgl3.Lwjgl3ApplicationConfiguration;
 import com.badlogic.gdx.graphics.glutils.HdpiMode;
@@ -13,7 +14,8 @@ public class Bootloader {
             config.setTitle("DiceOS");
             config.setFullscreenMode(Lwjgl3ApplicationConfiguration.getDisplayMode());
             config.setHdpiMode(HdpiMode.Pixels);
-            new Lwjgl3Application(beanScope.get(DiceOS.class), config);
+            beanScope.get(DiceOS.class);
+            new Lwjgl3Application(beanScope.get(DiceOSAdapter.class), config);
         }
     }
 }

src/main/java/be/seeseemelk/diceos/system/DiceOS.java

@@ -1,123 +1,36 @@
 package be.seeseemelk.diceos.system;
 
-import be.seeseemelk.diceos.system.gfx.GraphicsContext;
-import com.badlogic.gdx.ApplicationAdapter;
-import com.badlogic.gdx.Gdx;
-import com.badlogic.gdx.graphics.Color;
-import com.badlogic.gdx.graphics.Texture;
-import com.badlogic.gdx.graphics.g2d.BitmapFont;
-import com.badlogic.gdx.graphics.g2d.TextureRegion;
-import com.badlogic.gdx.utils.ScreenUtils;
-import com.badlogic.gdx.utils.viewport.ScreenViewport;
-import com.badlogic.gdx.utils.viewport.Viewport;
 import io.avaje.inject.Component;
+import io.avaje.inject.PostConstruct;
 import lombok.RequiredArgsConstructor;
-import lombok.extern.slf4j.Slf4j;
 
-import java.util.List;
-
-@Slf4j
-@Component
 @RequiredArgsConstructor
-public class DiceOS extends ApplicationAdapter {
+@Component
+public class DiceOS {
+    private static DiceOS INSTANCE;
     private final ResourceLoader resourceLoader;
-    private final DisplayService display;
-    private final CursorService cursorService;
     private final WindowService windowService;
-    private final List<OnStartup> startupTasks;
-    private Texture clouds;
-    private Texture border;
-    private Viewport vmViewport;
-    private Viewport screenViewport;
-    private int scaling = 1;
-    private int offsetX = 0;
-    private int offsetY = 0;
-    private GraphicsContext gc;
 
-    private BitmapFont font;
+    @PostConstruct
-
+    void register() {
-    @Override
+        if (INSTANCE != null) {
-    public void create() {
+            throw new IllegalStateException("DiceOS already created");
-        log.info("DiceOS starting...");
+        }
-        clouds = resourceLoader.loadTexture("backgrounds/clouds.png");
+        INSTANCE = this;
-        border = resourceLoader.loadTexture("system/border.png");
-
-        screenViewport = new ScreenViewport();
-        vmViewport = new ScreenViewport();
-        vmViewport.update(display.getWidth(), display.getHeight(), true);
-
-        for (var task : startupTasks) {
-            task.onStartup();
     }
 
-        font = resourceLoader.loadFont("system/font");
+    public static DiceOS get() {
-
+        if (INSTANCE == null) {
-        log.info("DiceOS started!");
+            throw new IllegalStateException("ResourceLoader not initialized yet");
+        }
+        return INSTANCE;
     }
 
-    @Override
+    public static ResourceLoader getResourceLoader() {
-    public void resize(int width, int height) {
+        return INSTANCE.resourceLoader;
-        screenViewport.update(width, height, true);
-
-        int displayWidth = display.getWidth();
-        int displayHeight = display.getHeight();
-        scaling = Math.min(width / displayWidth, height / displayHeight);
-        offsetX = (width - (displayWidth * scaling)) / 2;
-        offsetY = (height - (displayHeight * scaling)) / 2;
-
-        cursorService.setScale(scaling);
-
-        gc = new GraphicsContext(screenViewport.getCamera(), display.getBatch(), displayHeight, displayWidth);
     }
 
-    @Override
+    public static WindowService getWindowService() {
-    public void render() {
+        return INSTANCE.windowService;
-        int mouseX = Gdx.input.getX();
-        int mouseY = display.getHeight() - Gdx.input.getY();
-        windowService.update(mouseX, mouseY, Gdx.input.isTouched());
-
-        cursorService.updateCursor();
-
-        ScreenUtils.clear(Color.BLACK);
-        vmViewport.apply();
-        display.getScreenBuffer().begin();
-        display.getBatch().setProjectionMatrix(vmViewport.getCamera().combined);
-        display.getBatch().begin();
-
-        ScreenUtils.clear(Color.GREEN);
-
-        // Render background
-        gc.draw(clouds, 0, 0);
-
-        // Render windows
-        windowService.render(gc);
-
-        gc.scissor(0, 0, gc.getWidth(), gc.getHeight(), windowService::paint);
-
-        // Render borders
-        var param = new GraphicsContext.Parameters();
-        gc.draw(border, 0, 0, param);
-        param.flipX = true;
-        gc.draw(border, display.getWidth() - 8, 0, param);
-        param.flipY = true;
-        gc.draw(border, display.getWidth() - 8, display.getHeight() - 8, param);
-        param.flipX = false;
-        gc.draw(border, 0, display.getHeight() - 8, param);
-
-        font.draw(display.getBatch(), "The quick brown fox jumps over the lazy dog", 6, display.getHeight() - 12);
-
-        // Finish rendering to screen buffer
-        display.getBatch().end();
-        display.getScreenBuffer().end();
-
-        // Render screen buffer to actual screen
-        screenViewport.apply();
-        display.getBatch().setProjectionMatrix(screenViewport.getCamera().combined);
-        display.getBatch().begin();
-        var texture = display.getScreenBuffer().getColorBufferTexture();
-        var textureRegion = new TextureRegion(texture);
-        textureRegion.flip(false, true);
-        display.getBatch().draw(textureRegion, offsetX, offsetY, display.getWidth() * scaling, display.getHeight() * scaling);
-        display.getBatch().end();
     }
 }

src/main/java/be/seeseemelk/diceos/system/DiceOSAdapter.java

@@ -0,0 +1,121 @@
+package be.seeseemelk.diceos.system;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import com.badlogic.gdx.ApplicationAdapter;
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.graphics.Color;
+import com.badlogic.gdx.graphics.Texture;
+import com.badlogic.gdx.graphics.g2d.BitmapFont;
+import com.badlogic.gdx.graphics.g2d.TextureRegion;
+import com.badlogic.gdx.utils.ScreenUtils;
+import com.badlogic.gdx.utils.viewport.ScreenViewport;
+import com.badlogic.gdx.utils.viewport.Viewport;
+import io.avaje.inject.Component;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.List;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class DiceOSAdapter extends ApplicationAdapter {
+    private final ResourceLoader resourceLoader;
+    private final DisplayService display;
+    private final CursorService cursorService;
+    private final WindowService windowService;
+    private final List<OnStartup> startupTasks;
+    private Texture clouds;
+    private Texture border;
+    private Viewport vmViewport;
+    private Viewport screenViewport;
+    private int scaling = 1;
+    private int offsetX = 0;
+    private int offsetY = 0;
+    private GraphicsContext gc;
+
+    private BitmapFont font;
+
+    @Override
+    public void create() {
+        log.info("DiceOS starting...");
+        clouds = resourceLoader.loadTexture("backgrounds/clouds.png");
+        border = resourceLoader.loadTexture("system/border.png");
+
+        screenViewport = new ScreenViewport();
+        vmViewport = new ScreenViewport();
+        vmViewport.update(display.getWidth(), display.getHeight(), true);
+
+        for (var task : startupTasks) {
+            task.onStartup();
+        }
+
+        font = resourceLoader.loadFont("system/font");
+
+        log.info("DiceOS started!");
+    }
+
+    @Override
+    public void resize(int width, int height) {
+        screenViewport.update(width, height, true);
+
+        int displayWidth = display.getWidth();
+        int displayHeight = display.getHeight();
+        scaling = Math.min(width / displayWidth, height / displayHeight);
+        offsetX = (width - (displayWidth * scaling)) / 2;
+        offsetY = (height - (displayHeight * scaling)) / 2;
+
+        cursorService.setScale(scaling);
+
+        gc = new GraphicsContext(screenViewport.getCamera(), display.getBatch(), displayHeight, displayWidth, font);
+    }
+
+    @Override
+    public void render() {
+        int mouseX = Gdx.input.getX();
+        int mouseY = display.getHeight() - Gdx.input.getY();
+        windowService.update(mouseX, mouseY, Gdx.input.isTouched());
+
+        cursorService.updateCursor();
+
+        ScreenUtils.clear(Color.BLACK);
+        vmViewport.apply();
+        display.getScreenBuffer().begin();
+        display.getBatch().setProjectionMatrix(vmViewport.getCamera().combined);
+        display.getBatch().begin();
+
+        ScreenUtils.clear(Color.GREEN);
+
+        // Render background
+        gc.draw(clouds, 0, 0);
+
+        // Render windows
+        windowService.paint(gc);
+
+        // Render borders
+        var param = new GraphicsContext.Parameters();
+        gc.draw(border, 0, 0, param);
+        param.flipX = true;
+        gc.draw(border, display.getWidth() - 8, 0, param);
+        param.flipY = true;
+        gc.draw(border, display.getWidth() - 8, display.getHeight() - 8, param);
+        param.flipX = false;
+        gc.draw(border, 0, display.getHeight() - 8, param);
+
+        // Finish rendering to screen buffer
+        display.getBatch().end();
+        display.getScreenBuffer().end();
+
+        // Render screen buffer to actual screen
+        screenViewport.apply();
+        display.getBatch().setProjectionMatrix(screenViewport.getCamera().combined);
+        display.getBatch().begin();
+        var texture = display.getScreenBuffer().getColorBufferTexture();
+        var textureRegion = new TextureRegion(texture);
+        textureRegion.flip(false, true);
+        display.getBatch().draw(textureRegion, offsetX, offsetY, display.getWidth() * scaling, display.getHeight() * scaling);
+        display.getBatch().end();
+    }
+
+
+}

src/main/java/be/seeseemelk/diceos/system/WindowService.java

@@ -1,8 +1,8 @@
 package be.seeseemelk.diceos.system;
 
 import be.seeseemelk.diceos.system.gfx.GraphicsContext;
-import be.seeseemelk.diceos.system.toolkit.Menubar;
 import be.seeseemelk.diceos.system.toolkit.Window;
+import be.seeseemelk.diceos.system.toolkit.menu.Menu;
 import com.badlogic.gdx.graphics.g2d.NinePatch;
 import io.avaje.inject.Component;
 import lombok.RequiredArgsConstructor;
@@ -16,21 +16,37 @@ public class WindowService implements OnStartup {
     private final ResourceLoader resourceLoader;
     private final List<Window> windows = new ArrayList<>();
     private NinePatch menubar;
-    private NinePatch windowDecoration;
+    private Menu menu;
-    private Menubar systemMenubar;
 
     @Override
     public void onStartup() {
         menubar = resourceLoader.loadNinePatch("system/menubar.png");
-        windowDecoration = resourceLoader.loadNinePatch("system/window.png");
 
-        systemMenubar = new Menubar()
+        menu = new Menu("Root");
-                .addItem("Dice")
+        menu.add(new Menu("Dice"));
-                .addItem("System");
+        menu.add(new Menu("System"));
     }
 
     public void spawnWindow(int x, int y, int width, int height) {
-        windows.add(new Window(x, y, width, height, windowDecoration));
+        windows.add(new Window(x, y, width, height, Window.Style.NORMAL));
+    }
+
+    /**
+     * Maps a window to be managed by this service.
+     * @param window The window to manage.
+     */
+    public void map(Window window) {
+        if (!windows.contains(window)) {
+            windows.add(window);
+        }
+    }
+
+    /**
+     * Unmaps a window, removing it from management.
+     * @param window The window to remove.
+     */
+    public void unmap(Window window) {
+        windows.remove(window);
     }
 
     public void update(int mouseX, int mouseY, boolean isTouched) {
@@ -39,14 +55,21 @@ public class WindowService implements OnStartup {
         }
     }
 
-    public void render(GraphicsContext gc) {
+    public void paint(GraphicsContext gc) {
         for (Window window : windows) {
             window.paint(gc);
         }
-    }
 
-    void paint(GraphicsContext gc) {
         // Render menubar
         gc.draw(menubar, 0, 0, gc.getWidth(), 14);
+
+        // Render menubar items
+        gc.save();
+        gc.translate(5, 0);
+        for (var submenu : menu.getItems()) {
+            submenu.paint(gc);
+            gc.translate(submenu.getWidth(), 0);
+        }
+        gc.restore();
     }
 }

src/main/java/be/seeseemelk/diceos/system/font/FontLoader.java

@@ -27,6 +27,7 @@ public class FontLoader {
         var region = new TextureRegion(texture);
 
         var data = new BitmapFont.BitmapFontData();
+        data.lineHeight = metadata.getGeneral().getLineHeight();
 
         var glyphMap = new Map2D<Integer, Integer, BitmapFont.Glyph>();
         var glyphLines = metadata.getGeneral().getOrder().split("\n");
@@ -65,6 +66,8 @@ public class FontLoader {
                 glyph.u2 = (float)widthTiming.glyphEnd / pixmap.getWidth();
                 glyph.v = (float)heightTiming.glyphStart / pixmap.getHeight();
                 glyph.v2 = (float)heightTiming.glyphEnd / pixmap.getHeight();
+
+                data.capHeight = Math.max(data.capHeight, heightTiming.getGlyphHeight());
             }
         }
 

src/main/java/be/seeseemelk/diceos/system/font/GeneralSection.java

@@ -15,4 +15,7 @@ public class GeneralSection {
      * The order of the glyphs in the image file.
      */
     private String order;
+
+    // @gemini implement
+    private int lineHeight;
 }

src/main/java/be/seeseemelk/diceos/system/gfx/GraphicsContext.java

@@ -1,16 +1,16 @@
 package be.seeseemelk.diceos.system.gfx;
 
+import be.seeseemelk.diceos.system.DiceOS;
 import com.badlogic.gdx.graphics.Camera;
 import com.badlogic.gdx.graphics.Texture;
 import com.badlogic.gdx.graphics.g2d.Batch;
+import com.badlogic.gdx.graphics.g2d.BitmapFont;
 import com.badlogic.gdx.graphics.g2d.NinePatch;
 import com.badlogic.gdx.math.Rectangle;
 import com.badlogic.gdx.scenes.scene2d.utils.ScissorStack;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 
-import java.util.function.Consumer;
-
 /**
  * Graphics context and rendering utilities.
  */
@@ -21,15 +21,49 @@ public class GraphicsContext {
     private final Batch batch;
     private final int height;
     private final int width;
+    private final BitmapFont font;
 
+    private final java.util.Stack<GraphicsState> stateStack = new java.util.Stack<>();
+
+    private static class GraphicsState {
+        private final com.badlogic.gdx.math.Matrix4 transform;
+        private final boolean scissorEnabled;
+
+        public GraphicsState(com.badlogic.gdx.math.Matrix4 transform, boolean scissorEnabled) {
+            this.transform = transform.cpy();
+            this.scissorEnabled = scissorEnabled;
+        }
+    }
+
+    /**
+     * Draws a NinePatch image at the specified coordinates and dimensions.
+     * @param image The NinePatch to draw.
+     * @param x The x-coordinate.
+     * @param y The y-coordinate.
+     * @param width The width.
+     * @param height The height.
+     */
     public void draw(NinePatch image, int x, int y, int width, int height) {
         image.draw(batch, x, getHeight() - height - y, width, height);
     }
 
+    /**
+     * Draws a texture at the specified coordinates.
+     * @param texture The texture to draw.
+     * @param x The x-coordinate.
+     * @param y The y-coordinate.
+     */
     public void draw(Texture texture, int x, int y) {
         draw(texture, x, y, Parameters.DEFAULT);
     }
 
+    /**
+     * Draws a texture with specific drawing parameters.
+     * @param texture The texture to draw.
+     * @param x The x-coordinate.
+     * @param y The y-coordinate.
+     * @param params Drawing parameters (flipX, flipY).
+     */
     public void draw(Texture texture, int x, int y, Parameters params) {
         batch.draw(texture,
                 x, getHeight() - y - texture.getHeight(), texture.getWidth(), texture.getHeight(),
@@ -37,22 +71,93 @@ public class GraphicsContext {
                 params.flipX, params.flipY);
     }
 
-    public void scissor(int x, int y, int width, int height, Consumer<GraphicsContext> callback) {
+    /**
-        var scissors = new Rectangle();
+     * Draws some text with the current font.
-        var clipBounds = new Rectangle(x, getHeight() - y - height, width, height);
+     * @param text The text to draw.
-        ScissorStack.calculateScissors(camera, batch.getTransformMatrix(), clipBounds, scissors);
+     * @param x The x coordinate to draw at.
-        batch.flush();
+     * @param y The y coordinate to draw at.
-        if (ScissorStack.pushScissors(scissors)) {
+     */
-            callback.accept(this);
+    public void draw(String text, int x, int y) {
-            batch.flush();
+        font.draw(batch, text, x, getHeight() - (y + font.getLineHeight()));
-            ScissorStack.popScissors();
-        }
     }
 
+    /**
+     * Fills a rectangular area with the currently set color.
+     * @param x The x-coordinate.
+     * @param y The y-coordinate.
+     * @param width The width.
+     * @param height The height.
+     */
+    public void fillRect(int x, int y, int width, int height) {
+        var texture = DiceOS.getResourceLoader().loadTexture("system/white.png");
+        batch.draw(texture, x, getHeight() - height - y, width, height); // This is not ideal.
+    }
+
+    /**
+     * Sets the color for subsequent drawing operations.
+     * @param r The red component (0-255).
+     * @param g The green component (0-255).
+     * @param b The blue component (0-255).
+     */
+    public void setColour(int r, int g, int b) {
+        batch.setColor(r / 255f, g / 255f, b / 255f, 1f);
+    }
+
+    /**
+     * Shifts the context to the right and down by some amount.
+     * Negative values move towards the opposite direction.
+     *
+     * @param x The number of pixels to move to the right by.
+     * @param y The number of pixels to move down by.
+     */
+    public void translate(int x, int y) {
+        batch.setTransformMatrix(batch.getTransformMatrix().trn(x, -y, 0));
+    }
+
+    /**
+     * Sets a clipping rectangle for subsequent draw operations.
+     *
+     * @param width  The width of the clipping area.
+     * @param height The height of the clipping area.
+     */
+    public void clip(int width, int height) {
+        var scissors = new Rectangle(0, 0, width, height);
+        ScissorStack.calculateScissors(camera, batch.getTransformMatrix(), scissors, scissors);
+        batch.flush();
+        ScissorStack.pushScissors(scissors);
+    }
+
+    /**
+     * Pushes the current state onto an internal stack.
+     * The state can later be restored using {@link #restore()}.
+     */
+    public void save() {
+        stateStack.push(new GraphicsState(batch.getTransformMatrix(), false));
+    }
+
+    /**
+     * Restores a state pushed by {@link #save()}
+     * @throws IllegalStateException if no state was pushed.
+     */
+    public void restore() {
+        if (stateStack.isEmpty()) {
+            throw new IllegalStateException("No state to restore");
+        }
+        batch.flush();
+        GraphicsState state = stateStack.pop();
+        batch.setTransformMatrix(state.transform);
+    }
+
+    /**
+     * Graphics drawing parameters.
+     */
     public static class Parameters {
         public final static Parameters DEFAULT = new Parameters();
 
+        /** Indicates if the x-axis should be flipped. */
         public boolean flipX = false;
+
+        /** Indicates if the y-axis should be flipped. */
         public boolean flipY = false;
     }
 }

src/main/java/be/seeseemelk/diceos/system/toolkit/Component.java

@@ -1,7 +1,40 @@
 package be.seeseemelk.diceos.system.toolkit;
 
 import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import be.seeseemelk.diceos.system.toolkit.events.Event;
+import be.seeseemelk.diceos.system.toolkit.events.InputEvent;
+import be.seeseemelk.diceos.system.toolkit.events.MouseEvent;
 
 public abstract class Component {
+    public abstract int getX();
+    public abstract int getY();
+    public abstract int getWidth();
+    public abstract int getHeight();
+
     public abstract void paint(GraphicsContext gc);
+
+    public void onEvent(Event event) {
+        switch (event) {
+            case InputEvent inputEvent -> onInputEvent(inputEvent);
+            default -> {}
+        }
+    }
+
+    public void onInputEvent(InputEvent event) {
+        switch (event) {
+            case MouseEvent mouseEvent -> onMouseEvent(mouseEvent);
+            default -> {}
+        }
+    }
+
+    public void onMouseEvent(MouseEvent event) {
+        switch (event) {
+            case be.seeseemelk.diceos.system.toolkit.events.MouseClickEvent mouseClickEvent -> onMouseClick(mouseClickEvent);
+            default -> {}
+        }
+    }
+
+    public void onMouseClick(be.seeseemelk.diceos.system.toolkit.events.MouseClickEvent event) {
+        // Default empty implementation
+    }
 }

src/main/java/be/seeseemelk/diceos/system/toolkit/Container.java

@@ -1,6 +1,7 @@
 package be.seeseemelk.diceos.system.toolkit;
 
 import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import be.seeseemelk.diceos.system.toolkit.events.MouseEvent;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -22,4 +23,14 @@ public abstract class Container extends Component {
             component.paint(gc);
         }
     }
+
+    @Override
+    public void onMouseEvent(MouseEvent event) {
+        super.onMouseEvent(event);
+        for (var component : components) {
+            if (component instanceof Window window && window.isHovered(event.getX(), event.getY())) {
+                component.onMouseEvent(event);
+            }
+        }
+    }
 }

src/main/java/be/seeseemelk/diceos/system/toolkit/Menubar.java

@@ -1,16 +0,0 @@
-package be.seeseemelk.diceos.system.toolkit;
-
-import lombok.Getter;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class Menubar {
-    @Getter
-    private final List<String> items = new ArrayList<>();
-
-    public Menubar addItem(String item) {
-        items.add(item);
-        return this;
-    }
-}

src/main/java/be/seeseemelk/diceos/system/toolkit/Window.java

@@ -1,24 +1,65 @@
 package be.seeseemelk.diceos.system.toolkit;
 
+import be.seeseemelk.diceos.system.DiceOS;
 import be.seeseemelk.diceos.system.gfx.GraphicsContext;
 import com.badlogic.gdx.graphics.g2d.NinePatch;
 import lombok.Getter;
 import lombok.Setter;
 
+/**
+ * Represents a window within the system.
+ */
 @Setter
 @Getter
 public class Window extends Container {
     private String title;
     private int x, y, width, height;
     private boolean active;
-    private NinePatch decoration;
+    private NinePatch borders;
 
-    public Window(int x, int y, int width, int height, NinePatch decoration) {
+    /**
+     * The style of window decorations to use.
+     */
+    public enum Style {
+        /**
+         * The standard style with a full window border.
+         * This is the default.
+         */
+        NORMAL,
+
+        /**
+         * No borders
+         */
+        NONE,
+    }
+
+    public Window(int x, int y, int width, int height, Style style) {
         this.x = x;
         this.y = y;
         this.width = width;
         this.height = height;
-        this.decoration = decoration;
+        setStyle(style);
+    }
+
+    public void setStyle(Style style) {
+        switch (style) {
+            case NORMAL -> borders = DiceOS.getResourceLoader().loadNinePatch("system/window.png");
+            case NONE -> borders = null;
+        }
+    }
+
+    /**
+     * Shows this window in the system.
+     */
+    public void show() {
+        DiceOS.getWindowService().map(this);
+    }
+
+    /**
+     * Hides this window from the system.
+     */
+    public void hide() {
+        DiceOS.getWindowService().unmap(this);
     }
 
     public boolean isHovered(int mouseX, int mouseY) {
@@ -47,8 +88,8 @@ public class Window extends Container {
 
     @Override
     public void paint(GraphicsContext gc) {
-        if (decoration != null) {
+        if (borders != null) {
-            decoration.draw(gc.getBatch(), x, y, width, height);
+            borders.draw(gc.getBatch(), x, gc.getHeight() - height - y, width, height);
         }
         super.paint(gc);
     }

src/main/java/be/seeseemelk/diceos/system/toolkit/events/Event.java

@@ -0,0 +1,4 @@
+package be.seeseemelk.diceos.system.toolkit.events;
+
+public abstract class Event {
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/events/InputEvent.java

@@ -0,0 +1,4 @@
+package be.seeseemelk.diceos.system.toolkit.events;
+
+public abstract class InputEvent extends Event {
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/events/MouseClickEvent.java

@@ -0,0 +1,25 @@
+package be.seeseemelk.diceos.system.toolkit.events;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Event representing a mouse button click.
+ */
+@Getter
+@RequiredArgsConstructor
+public class MouseClickEvent extends MouseEvent {
+    private final int x;
+    private final int y;
+
+    /**
+     * The mouse button that was clicked.
+     */
+    private final Button button;
+
+    public enum Button {
+        LEFT,
+        RIGHT,
+        ;
+    }
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/events/MouseEvent.java

@@ -0,0 +1,16 @@
+package be.seeseemelk.diceos.system.toolkit.events;
+
+/**
+ * Base class for all mouse-related input events.
+ */
+public abstract class MouseEvent extends InputEvent {
+    /**
+     * @return The x-coordinate of the mouse event.
+     */
+    public abstract int getX();
+
+    /**
+     * @return The y-coordinate of the mouse event.
+     */
+    public abstract int getY();
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/menu/Menu.java

@@ -0,0 +1,53 @@
+package be.seeseemelk.diceos.system.toolkit.menu;
+
+import be.seeseemelk.diceos.system.DiceOS;
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@RequiredArgsConstructor
+@Getter
+public class Menu implements MenuItem {
+    private final String title;
+    private final List<MenuItem> items = new ArrayList<>();
+
+    public Menu add(MenuItem item) {
+        items.add(item);
+        return this;
+    }
+
+    public Menu remove(MenuItem item) {
+        items.remove(item);
+        return this;
+    }
+
+    @Override
+    public int getWidth() {
+        return items.stream().mapToInt(MenuItem::getWidth).max().orElse(0);
+    }
+
+    @Override
+    public int getHeight() {
+        return items.stream().mapToInt(MenuItem::getHeight).sum();
+    }
+
+    /**
+     * Opens the popup at a specific coordinate.
+     *
+     * @param x The x-coordinate.
+     * @param y The y-coordinate.
+     * @return The created MenuPopup.
+     */
+    public MenuPopup show(int x, int y) {
+        return new MenuPopup(this, x, y);
+    }
+
+    @Override
+    public void paint(GraphicsContext gc) {
+        // Renders the menu as a simple menu button
+        gc.draw(title, 0, 5);
+    }
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/menu/MenuButton.java

@@ -0,0 +1,41 @@
+package be.seeseemelk.diceos.system.toolkit.menu;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class MenuButton implements MenuItem {
+    private String text;
+    private Runnable callback;
+
+    public MenuButton(String text) {
+        this.text = text;
+    }
+
+    public void onClick(Runnable callback) {
+        this.callback = callback;
+    }
+
+    public void click() {
+        if (callback != null) {
+            callback.run();
+        }
+    }
+
+    @Override
+    public int getWidth() {
+        return text.length() * 8 + 10; // Simple approximation for now
+    }
+
+    @Override
+    public int getHeight() {
+        return 16;
+    }
+
+    @Override
+    public void paint(GraphicsContext gc) {
+        // Implement painting logic
+    }
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/menu/MenuDivider.java

@@ -0,0 +1,20 @@
+package be.seeseemelk.diceos.system.toolkit.menu;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+
+public class MenuDivider implements MenuItem {
+    @Override
+    public int getWidth() {
+        return 100;
+    }
+
+    @Override
+    public int getHeight() {
+        return 4;
+    }
+
+    @Override
+    public void paint(GraphicsContext gc) {
+        // Implement divider drawing
+    }
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/menu/MenuItem.java

@@ -0,0 +1,9 @@
+package be.seeseemelk.diceos.system.toolkit.menu;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+
+public interface MenuItem {
+    int getWidth();
+    int getHeight();
+    void paint(GraphicsContext gc);
+}

src/main/java/be/seeseemelk/diceos/system/toolkit/menu/MenuPopup.java

@@ -0,0 +1,16 @@
+package be.seeseemelk.diceos.system.toolkit.menu;
+
+import be.seeseemelk.diceos.system.toolkit.Window;
+
+/**
+ * A visisble menu popup.
+ */
+public class MenuPopup {
+    private final Menu menu;
+    private final Window window;
+
+    public MenuPopup(Menu menu, int x, int y) {
+        this.menu = menu;
+        this.window = new Window(x, y, menu.getWidth(), menu.getHeight(), Window.Style.NONE);
+    }
+}

src/main/resources/system/font.toml

@@ -4,6 +4,7 @@ order = """
 aAbBcCdDeEfFgGhHiIjJkKlLmMnN
 oOpPqQrRsStTuUvVwWxXyYzZ
 """
+lineHeight = 7
 
 [padding]
 horizontal = 1