From 15081a8fe0e7d314ae2d228bfae5a2e6773fb5ff Mon Sep 17 00:00:00 2001
From: Ellpeck <megamaximal@gmail.com>
Date: Sat, 10 Aug 2019 19:23:08 +0200
Subject: [PATCH] added a text field

---
 MLEM.Ui/Elements/Paragraph.cs |  1 -
 MLEM.Ui/Elements/TextField.cs | 75 +++++++++++++++++++++++++++++++++++
 Tests/GameImpl.cs             |  2 +
 3 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 MLEM.Ui/Elements/TextField.cs

diff --git a/MLEM.Ui/Elements/Paragraph.cs b/MLEM.Ui/Elements/Paragraph.cs
index a13fcab..b504faf 100644
--- a/MLEM.Ui/Elements/Paragraph.cs
+++ b/MLEM.Ui/Elements/Paragraph.cs
@@ -25,7 +25,6 @@ namespace MLEM.Ui.Elements {
                 this.text = value;
                 this.SetDirty();
             }
-
         }
 
         public Paragraph(Anchor anchor, float width, string text, bool centerText = false, IGenericFont font = null) : base(anchor, new Vector2(width, 0)) {
diff --git a/MLEM.Ui/Elements/TextField.cs b/MLEM.Ui/Elements/TextField.cs
new file mode 100644
index 0000000..bd75a0b
--- /dev/null
+++ b/MLEM.Ui/Elements/TextField.cs
@@ -0,0 +1,75 @@
+using System;
+using System.Text;
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using Microsoft.Xna.Framework.Input;
+using MLEM.Font;
+using MLEM.Textures;
+
+namespace MLEM.Ui.Elements {
+    public class TextField : Element {
+
+        public static NinePatch DefaultTexture;
+        public static NinePatch DefaultHoveredTexture;
+        public static Color DefaultHoveredColor = Color.LightGray;
+
+        public NinePatch Texture = DefaultTexture;
+        public NinePatch HoveredTexture = DefaultHoveredTexture;
+        public Color HoveredColor = DefaultHoveredColor;
+        public float TextScale;
+        public readonly StringBuilder Text = new StringBuilder();
+        public TextChanged OnTextChange;
+        public int MaxTextLength = int.MaxValue;
+        public float TextOffsetX = 4;
+        private readonly IGenericFont font;
+        private double caretBlinkTimer;
+
+        public TextField(Anchor anchor, Vector2 size, IGenericFont font = null) : base(anchor, size) {
+            this.font = font ?? Paragraph.DefaultFont;
+            this.TextScale = Paragraph.DefaultTextScale;
+            this.OnTextInput += (element, key, character) => {
+                if (!this.IsSelected)
+                    return;
+                var textChanged = false;
+                if (key == Keys.Back) {
+                    if (this.Text.Length > 0) {
+                        this.Text.Remove(this.Text.Length - 1, 1);
+                        textChanged = true;
+                    }
+                } else if (!char.IsControl(character)) {
+                    if (this.Text.Length < this.MaxTextLength) {
+                        this.Text.Append(character);
+                        textChanged = true;
+                    }
+                }
+                if (textChanged)
+                    this.OnTextChange?.Invoke(this, this.Text.ToString());
+            };
+        }
+
+        public override void Update(GameTime time) {
+            base.Update(time);
+
+            this.caretBlinkTimer += time.ElapsedGameTime.TotalSeconds;
+            if (this.caretBlinkTimer >= 1)
+                this.caretBlinkTimer = 0;
+        }
+
+        public override void Draw(GameTime time, SpriteBatch batch, float alpha) {
+            var tex = this.Texture;
+            var color = Color.White * alpha;
+            if (this.IsMouseOver) {
+                if (this.HoveredTexture != null)
+                    tex = this.HoveredTexture;
+                color = this.HoveredColor * alpha;
+            }
+            batch.Draw(tex, this.DisplayArea, color);
+            var caret = this.IsSelected && this.caretBlinkTimer >= 0.5F ? "|" : "";
+            this.font.DrawCenteredString(batch, this.Text + caret, this.DisplayArea.Location.ToVector2() + new Vector2(this.TextOffsetX, this.DisplayArea.Height / 2), this.TextScale, Color.White * alpha, false, true);
+            base.Draw(time, batch, alpha);
+        }
+
+        public delegate void TextChanged(TextField field, string text);
+
+    }
+}
\ No newline at end of file
diff --git a/Tests/GameImpl.cs b/Tests/GameImpl.cs
index 1300702..de44b4a 100644
--- a/Tests/GameImpl.cs
+++ b/Tests/GameImpl.cs
@@ -28,6 +28,7 @@ namespace Tests {
             Paragraph.DefaultFont = new GenericSpriteFont(LoadContent<SpriteFont>("Fonts/TestFont"));
             Paragraph.DefaultTextScale = 0.2F;
             Button.DefaultTexture = new NinePatch(new TextureRegion(this.testTexture, 24, 8, 16, 16), 4);
+            TextField.DefaultTexture = Button.DefaultTexture;
             this.UiSystem.GlobalScale = 5;
 
             var root = new Panel(Anchor.BottomLeft, new Vector2(100, 100), new Point(5, 5), this.testPatch);
@@ -39,6 +40,7 @@ namespace Tests {
                         image.IsHidden = !image.IsHidden;
                 }
             });
+            root.AddChild(new TextField(Anchor.AutoLeft, new Vector2(1, 15)));
             this.UiSystem.Add("Test", root);
         }