Add an item display widget (WItem)

src/main/java/io/github/cottonmc/cotton/gui/ValidatedSlot.java

@@ -43,6 +43,9 @@ public ItemStack getStack() {
 
 	/**
 	 * Returns true if the item in this slot can be modified by players.
+	 *
+	 * @return true if this slot is modifiable
+	 * @since 1.8.0
 	 */
 	public boolean isModifiable() {
 		return modifiable;

src/main/java/io/github/cottonmc/cotton/gui/widget/WItem.java

@@ -0,0 +1,118 @@
+package io.github.cottonmc.cotton.gui.widget;
+
+import com.google.common.collect.ImmutableList;
+import com.mojang.blaze3d.systems.RenderSystem;
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.item.ItemRenderer;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemConvertible;
+import net.minecraft.item.ItemStack;
+import net.minecraft.tag.Tag;
+
+import java.util.*;
+
+/**
+ * A widget that displays an item or a list of items.
+ *
+ * @since 1.8.0
+ */
+public class WItem extends WWidget {
+	private List<ItemStack> items;
+	private int duration = 25;
+	private int ticks = 0;
+	private int current = 0;
+
+	public WItem(List<ItemStack> items) {
+		setItems(items);
+	}
+
+	public WItem(Tag<? extends ItemConvertible> tag) {
+		this(getRenderStacks(tag));
+	}
+
+	public WItem(ItemStack stack) {
+		this(Collections.singletonList(stack));
+	}
+
+	@Override
+	public boolean canResize() {
+		return true;
+	}
+
+	@Override
+	public void tick() {
+		if (ticks++ >= duration) {
+			ticks = 0;
+			current = (current + 1) % items.size();
+		}
+	}
+
+	@Environment(EnvType.CLIENT)
+	@Override
+	public void paintBackground(int x, int y, int mouseX, int mouseY) {
+		RenderSystem.pushMatrix();
+		RenderSystem.enableDepthTest();
+		RenderSystem.translatef(x, y, 0);
+		RenderSystem.scalef(1.2f, 1.2f, 1.0f);
+
+		MinecraftClient mc = MinecraftClient.getInstance();
+		ItemRenderer renderer = mc.getItemRenderer();
+		renderer.zOffset = 100f;
+		renderer.renderGuiItem(mc.player, items.get(current), getWidth() / 2 - 9, getHeight() / 2 - 9);
+		renderer.zOffset = 0f;
+
+		RenderSystem.popMatrix();
+	}
+
+	/**
+	 * Returns the animation duration of this {@code WItem}.
+	 *
+	 * <p>Defaults to 25 screen ticks.
+	 */
+	public int getDuration() {
+		return duration;
+	}
+
+	public WItem setDuration(int duration) {
+		this.duration = duration;
+		return this;
+	}
+
+	public List<ItemStack> getItems() {
+		return items;
+	}
+
+	/**
+	 * Sets the item list of this {@code WItem} and resets the animation state.
+	 *
+	 * @param items the new item list
+	 * @return this instance
+	 */
+	public WItem setItems(List<ItemStack> items) {
+		Objects.requireNonNull(items, "stacks == null!");
+		if (items.isEmpty()) throw new IllegalArgumentException("The stack list is empty!");
+
+		this.items = items;
+
+		// Reset the state
+		current = 0;
+		ticks = 0;
+
+		return this;
+	}
+
+	/**
+	 * Gets the render stacks ({@link Item#getStackForRender()}) of each item in a tag.
+	 */
+	private static List<ItemStack> getRenderStacks(Tag<? extends ItemConvertible> tag) {
+		ImmutableList.Builder<ItemStack> builder = ImmutableList.builder();
+
+		for (ItemConvertible item : tag.values()) {
+			builder.add(item.asItem().getStackForRender());
+		}
+
+		return builder.build();
+	}
+}

src/main/java/io/github/cottonmc/cotton/gui/widget/WItemSlot.java

@@ -87,6 +87,9 @@ public boolean isBigSlot() {
 
 	/**
 	 * Returns true if the contents of this {@code WItemSlot} can be modified by players.
+	 *
+	 * @return true if this slot is modifiable
+	 * @since 1.8.0
 	 */
 	public boolean isModifiable() {
 		return modifiable;