Fix IOOBE when WTextField.scrollOffset was outside the string

Fixes #154. Also documented some WTextField methods.

3 files changed, 59 insertions, 30 deletions

diff --git a/GuiTest/src/main/java/io/github/cottonmc/test/client/LibGuiTestClient.java b/GuiTest/src/main/java/io/github/cottonmc/test/client/LibGuiTestClient.java
index efdcd3f..38545fa 100644
--- a/GuiTest/src/main/java/io/github/cottonmc/test/client/LibGuiTestClient.java
+++ b/GuiTest/src/main/java/io/github/cottonmc/test/client/LibGuiTestClient.java
@@ -1,19 +1,25 @@
 package io.github.cottonmc.test.client;
 
+import com.mojang.brigadier.Command;
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.client.command.v1.ClientCommandManager;
+import net.fabricmc.fabric.api.client.command.v1.FabricClientCommandSource;
 import net.fabricmc.fabric.api.client.screenhandler.v1.ScreenRegistry;
+import net.minecraft.client.MinecraftClient;
 import net.minecraft.text.LiteralText;
 
 import io.github.cottonmc.cotton.gui.client.CottonClientScreen;
 import io.github.cottonmc.cotton.gui.client.CottonHud;
 import io.github.cottonmc.cotton.gui.client.CottonInventoryScreen;
+import io.github.cottonmc.cotton.gui.client.LightweightGuiDescription;
 import io.github.cottonmc.cotton.gui.impl.modmenu.ConfigGui;
 import io.github.cottonmc.cotton.gui.widget.WLabel;
 import io.github.cottonmc.test.LibGuiTest;
 import io.github.cottonmc.test.ReallySimpleDescription;
 import io.github.cottonmc.test.TestDescription;
 
+import java.util.function.Function;
+
 import static net.fabricmc.fabric.api.client.command.v1.ClientCommandManager.literal;
 
 public class LibGuiTestClient implements ClientModInitializer {
@@ -35,35 +41,19 @@ public class LibGuiTestClient implements ClientModInitializer {
 
 		ClientCommandManager.DISPATCHER.register(
 				literal("libgui")
-						.then(literal("config").executes(context -> {
-							var client = context.getSource().getClient();
-							client.send(() -> {
-								client.setScreen(new CottonClientScreen(new ConfigGui(client.currentScreen)));
-							});
-							return 0;
-						}))
-						.then(literal("tab").executes(context -> {
-							var client = context.getSource().getClient();
-							client.send(() -> {
-								client.setScreen(new CottonClientScreen(new TabTestGui()));
-							});
-							return 0;
-						}))
-						.then(literal("scrolling").executes(context -> {
-							var client = context.getSource().getClient();
-							client.send(() -> {
-								client.setScreen(new CottonClientScreen(new ScrollingTestGui()));
-							});
-							return 0;
-						}))
-						.then(literal("insets").executes(context -> {
-							var client = context.getSource().getClient();
-							client.send(() -> {
-								client.setScreen(new CottonClientScreen(new InsetsTestGui()));
-							});
-							return 0;
-						}))
+						.then(literal("config").executes(openScreen(client -> new ConfigGui(client.currentScreen))))
+						.then(literal("tab").executes(openScreen(client -> new TabTestGui())))
+						.then(literal("scrolling").executes(openScreen(client -> new ScrollingTestGui())))
+						.then(literal("insets").executes(openScreen(client -> new InsetsTestGui())))
+						.then(literal("textfield").executes(openScreen(client -> new TextFieldTestGui())))
 		);
 	}
 
+	private static Command<FabricClientCommandSource> openScreen(Function<MinecraftClient, LightweightGuiDescription> screenFactory) {
+		return context -> {
+			var client = context.getSource().getClient();
+			client.send(() -> client.setScreen(new CottonClientScreen(screenFactory.apply(client))));
+			return Command.SINGLE_SUCCESS;
+		};
+	}
 }
diff --git a/GuiTest/src/main/java/io/github/cottonmc/test/client/TextFieldTestGui.java b/GuiTest/src/main/java/io/github/cottonmc/test/client/TextFieldTestGui.java
new file mode 100644
index 0000000..dc2b68c
--- /dev/null
+++ b/GuiTest/src/main/java/io/github/cottonmc/test/client/TextFieldTestGui.java
@@ -0,0 +1,20 @@
+package io.github.cottonmc.test.client;
+
+import net.minecraft.item.Items;
+import net.minecraft.text.LiteralText;
+
+import io.github.cottonmc.cotton.gui.client.LightweightGuiDescription;
+import io.github.cottonmc.cotton.gui.widget.WButton;
+import io.github.cottonmc.cotton.gui.widget.WGridPanel;
+import io.github.cottonmc.cotton.gui.widget.WTextField;
+import io.github.cottonmc.cotton.gui.widget.icon.ItemIcon;
+
+public class TextFieldTestGui extends LightweightGuiDescription {
+	public TextFieldTestGui() {
+		WGridPanel grid = (WGridPanel) rootPanel;
+		WTextField textField = new WTextField(new LiteralText("Type something")).setMaxLength(Integer.MAX_VALUE);
+		grid.add(textField, 0, 0, 6, 1);
+		grid.add(new WButton(new ItemIcon(Items.BARRIER), new LiteralText("Clear")).setOnClick(() -> textField.setText("")), 0, 2, 6, 1);
+		rootPanel.validate(this);
+	}
+}
diff --git a/src/main/java/io/github/cottonmc/cotton/gui/widget/WTextField.java b/src/main/java/io/github/cottonmc/cotton/gui/widget/WTextField.java
index b566f7e..64bf367 100644
--- a/src/main/java/io/github/cottonmc/cotton/gui/widget/WTextField.java
+++ b/src/main/java/io/github/cottonmc/cotton/gui/widget/WTextField.java
@@ -85,6 +85,13 @@ public class WTextField extends WWidget {
 		this.suggestion = suggestion;
 	}
 
+	/**
+	 * Sets the text of this text field.
+	 * If the text is more than the {@linkplain #getMaxLength() max length},
+	 * it'll be shortened to the max length.
+	 *
+	 * @param s the new text
+	 */
 	public void setText(String s) {
 		setTextWithResult(s);
 	}
@@ -92,13 +99,19 @@ public class WTextField extends WWidget {
 	private boolean setTextWithResult(String s) {
 		if (this.textPredicate == null || this.textPredicate.test(s)) {
 			this.text = (s.length() > maxLength) ? s.substring(0, maxLength) : s;
+			// Call change listener
 			if (onChanged != null) onChanged.accept(this.text);
+			// Reset cursor if needed
+			if (cursor >= this.text.length()) cursor = this.text.length() - 1;
 			return true;
 		}
 
 		return false;
 	}
 
+	/**
+	 * {@return the text in this text field}
+	 */
 	public String getText() {
 		return this.text;
 	}
@@ -141,6 +154,11 @@ public class WTextField extends WWidget {
 			scrollOffset = cursor;
 		}
 
+		checkScrollOffset();
+	}
+
+	@Environment(EnvType.CLIENT)
+	private void checkScrollOffset() {
 		int rightMostScrollOffset = text.length() - font.trimToWidth(text, width - TEXT_PADDING_X * 2, true).length();
 		scrollOffset = Math.min(rightMostScrollOffset, scrollOffset);
 	}
@@ -217,6 +235,7 @@ public class WTextField extends WWidget {
 	protected void renderTextField(MatrixStack matrices, int x, int y) {
 		if (this.font == null) this.font = MinecraftClient.getInstance().textRenderer;
 
+		checkScrollOffset();
 		String visibleText = font.trimToWidth(this.text.substring(this.scrollOffset), this.width - 2 * TEXT_PADDING_X);
 		renderBox(matrices, x, y);
 		renderText(matrices, x, y, visibleText);
@@ -263,8 +282,7 @@ public class WTextField extends WWidget {
 	public WTextField setMaxLength(int max) {
 		this.maxLength = max;
 		if (this.text.length() > max) {
-			this.text = this.text.substring(0, max);
-			this.onChanged.accept(this.text);
+			setText(this.text.substring(0, max));
 		}
 		return this;
 	}
@@ -337,6 +355,7 @@ public class WTextField extends WWidget {
 	public int getCaretPosition(int clickX) {
 		if (clickX < 0) return 0;
 		int lastPos = 0;
+		checkScrollOffset();
 		String string = text.substring(scrollOffset);
 		for (int i = 0; i < string.length(); i++) {
 			int w = font.getWidth(string.charAt(i) + "");