Add Component and Container classes for UI structure and implement scissor method in GraphicsContext

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

@@ -66,7 +66,7 @@ public class DiceOS extends ApplicationAdapter {
 
         cursorService.setScale(scaling);
 
-        gc = new GraphicsContext(display.getBatch(), displayHeight, displayWidth);
+        gc = new GraphicsContext(screenViewport.getCamera(), display.getBatch(), displayHeight, displayWidth);
     }
 
     @Override
@@ -84,7 +84,7 @@ public class DiceOS extends ApplicationAdapter {
         // Render background
         gc.draw(clouds, 0, 0);
 
-        windowService.paint(gc);
+        gc.scissor(0, 0, gc.getWidth(), gc.getHeight(), windowService::paint);
 
         // Render borders
         var param = new GraphicsContext.Parameters();

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

@@ -24,6 +24,6 @@ public class WindowService implements OnStartup {
 
     void paint(GraphicsContext gc) {
         // Render menubar
-        gc.draw(menubar, 0, 0, gc.getWidth(), 13);
+        gc.draw(menubar, 0, 0, gc.getWidth(), 14);
     }
 }

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

@@ -1,17 +1,23 @@
 package be.seeseemelk.diceos.system.gfx;
 
+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.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.
  */
 @Getter
 @RequiredArgsConstructor
 public class GraphicsContext {
+    private final Camera camera;
     private final Batch batch;
     private final int height;
     private final int width;
@@ -31,6 +37,18 @@ 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();
+        var clipBounds = new Rectangle(x, getHeight() - y - height, width, height);
+        ScissorStack.calculateScissors(camera, batch.getTransformMatrix(), clipBounds, scissors);
+        batch.flush();
+        if (ScissorStack.pushScissors(scissors)) {
+            callback.accept(this);
+            batch.flush();
+            ScissorStack.popScissors();
+        }
+    }
+
     public static class Parameters {
         public final static Parameters DEFAULT = new Parameters();
 

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

@@ -0,0 +1,7 @@
+package be.seeseemelk.diceos.system.toolkit;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+
+public abstract class Component {
+    public abstract void paint(GraphicsContext gc);
+}

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

@@ -0,0 +1,25 @@
+package be.seeseemelk.diceos.system.toolkit;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class Container extends Component {
+    private final List<Component> components = new ArrayList<>();
+
+    public void addComponent(Component component) {
+        components.add(component);
+    }
+
+    public void removeComponent(Component component) {
+        components.remove(component);
+    }
+
+    @Override
+    public void paint(GraphicsContext gc) {
+        for (Component component : components) {
+            component.paint(gc);
+        }
+    }
+}

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

@@ -0,0 +1,16 @@
+package be.seeseemelk.diceos.system.toolkit;
+
+import be.seeseemelk.diceos.system.gfx.GraphicsContext;
+import lombok.Getter;
+import lombok.Setter;
+
+@Setter
+@Getter
+public class Window extends Container {
+    private String title;
+
+    @Override
+    public void paint(GraphicsContext gc) {
+        super.paint(gc);
+    }
+}