Refactor UI components for flexible layout handling

Replaced static stack length management with dynamic gap sizing and layout direction handling in `StackContainer`. Updated `FocusHandler` to remove dependency on `ParentUIComponent`, simplifying the initialization and management of focus. Adjusted screen initialization in `TestScreen` to utilize a vertical layout with a configurable gap, enhancing UI modularity and maintainability.

common-testmod/src/main/java/me/pandamods/test/client/screen/TestScreen.java

@@ -23,7 +23,11 @@
 
 public class TestScreen extends BasePLScreen<StackContainer> {
 	public TestScreen() {
-		super(StackContainer::new);
+		super(() -> {
+			StackContainer stack = StackContainer.createVerticalLayout();
+			stack.setGapSize(4);
+			return stack;
+		});
 	}
 
 	@Override

common/src/main/java/me/pandamods/pandalib/client/screen/BaseParentUIComponent.java

@@ -16,10 +16,9 @@
 import me.pandamods.pandalib.client.screen.core.UIComponent;
 import me.pandamods.pandalib.client.screen.utils.FocusHandler;
 import me.pandamods.pandalib.client.screen.utils.RenderContext;
-import org.jetbrains.annotations.Nullable;
 
 public abstract class BaseParentUIComponent extends BaseUIComponent implements ParentUIComponent {
-	protected FocusHandler focusHandler = new FocusHandler(this);
+	protected FocusHandler focusHandler;
 
 	@Override
 	public void render(RenderContext context, int mouseX, int mouseY, float partialTicks) {
@@ -55,9 +54,14 @@ public void updateChildState(UIComponent uiComponent) {
 	protected abstract void addChild(UIComponent UIComponent);
 	protected abstract void removeChild(UIComponent UIComponent);
 
+	@Override
+	public void mount(ParentUIComponent parent) {
+		super.mount(parent);
+		this.focusHandler = parent != null ? parent.getFocusHandler() : new FocusHandler();
+	}
+
 	@Override
 	public FocusHandler getFocusHandler() {
-		FocusHandler focusHandler = super.getFocusHandler();
-		return focusHandler != null ? focusHandler : this.focusHandler;
+		return this.focusHandler;
 	}
 }

common/src/main/java/me/pandamods/pandalib/client/screen/layouts/StackContainer.java

@@ -14,30 +14,34 @@
 
 import me.pandamods.pandalib.client.screen.BaseParentUIComponent;
 import me.pandamods.pandalib.client.screen.core.UIComponent;
-import me.pandamods.pandalib.client.screen.utils.RenderContext;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 public class StackContainer extends BaseParentUIComponent {
 	private final List<UIComponent> children = new ArrayList<>();
 	private final List<UIComponent> viewChildren = Collections.unmodifiableList(children);
 
-	private boolean realign = true;
-	private int stackLength = 0;
+	protected Direction direction;
+	protected int gapSize = 0;
 
-	@Override
-	protected void renderChildren(RenderContext context, int mouseX, int mouseY, float partialTicks) {
-		if (realign) stackLength = 0;
-		super.renderChildren(context, mouseX, mouseY, partialTicks);
+	private int contentWidth = 0;
+	private int contentHeight = 0;
+
+	public static StackContainer createHorizontalLayout() {
+		return new StackContainer(Direction.HORIZONTAL);
 	}
 
-	@Override
-	public void renderChild(UIComponent child, RenderContext context, int mouseX, int mouseY, float partialTicks) {
-		if (realign) child.setY(stackLength);
-		super.renderChild(child, context, mouseX, mouseY, partialTicks);
-		if (realign) stackLength += child.getHeight();
+	public static StackContainer createVerticalLayout() {
+		return new StackContainer(Direction.VERTICAL);
+	}
+
+	public StackContainer(Direction direction) {
+		this.direction = direction;
 	}
 
 	@Override
@@ -61,10 +65,64 @@ protected void removeChild(UIComponent UIComponent) {
 		children.remove(UIComponent);
 	}
 
-	/**
-	 * Realigns children next frame
-	 */
+	public void setDirection(Direction direction) {
+		this.direction = direction;
+		this.align();
+	}
+
+	public Direction getDirection() {
+		return direction;
+	}
+
+	public void setGapSize(int gapSize) {
+		this.gapSize = gapSize;
+	}
+
+	public int getGapSize() {
+		return gapSize;
+	}
+
 	public void align() {
-		realign = true;
+		int contentLength = 0;
+		int contentSize = 0;
+
+		Iterator<UIComponent> iterator = this.children.iterator();
+		while (iterator.hasNext()) {
+			UIComponent child = iterator.next();
+			Consumer<Integer> setPos = this.direction == Direction.HORIZONTAL ? child::setX : child::setY;
+			Supplier<Integer> getLength = this.direction == Direction.HORIZONTAL ? child::getWidth : child::getHeight;
+			Supplier<Integer> getSize = this.direction == Direction.HORIZONTAL ? child::getHeight : child::getWidth;
+
+			setPos.accept(contentLength);
+			contentLength += getLength.get();
+			if (iterator.hasNext()) {
+				contentLength += gapSize;
+			}
+			contentSize = Math.max(contentSize, getSize.get());
+		}
+
+		switch (this.direction) {
+			case HORIZONTAL -> {
+				contentWidth = contentLength;
+				contentHeight = contentSize;
+			}
+			case VERTICAL -> {
+				contentHeight = contentLength;
+				contentWidth = contentSize;
+			}
+		}
+	}
+
+	public int getContentWidth() {
+		return contentWidth;
+	}
+
+	public int getContentHeight() {
+		return contentHeight;
+	}
+
+	public enum Direction {
+		HORIZONTAL,
+		VERTICAL
 	}
 }

common/src/main/java/me/pandamods/pandalib/client/screen/utils/FocusHandler.java

@@ -12,22 +12,15 @@
 
 package me.pandamods.pandalib.client.screen.utils;
 
-import me.pandamods.pandalib.client.screen.BaseParentUIComponent;
-import me.pandamods.pandalib.client.screen.core.ParentUIComponent;
 import me.pandamods.pandalib.client.screen.core.UIComponent;
 import org.jetbrains.annotations.Nullable;
 
 public class FocusHandler {
-	private final ParentUIComponent root;
-
 	@Nullable
 	protected UIComponent focused;
 
-	public FocusHandler(ParentUIComponent root) {
-		this.root = root;
-	}
-
 	public void focus(UIComponent focused) {
+		if (this.focused == focused) return;
 		if (this.focused != null) this.focused.onFocusLost();
 		this.focused = focused;
 		if (this.focused != null) this.focused.onFocusGained();
@@ -45,8 +38,4 @@ public UIComponent getFocused() {
 	public boolean isFocused(UIComponent component) {
 		return focused == component;
 	}
-
-	public ParentUIComponent getRoot() {
-		return root;
-	}
 }