Begin working on an IconButton class, and demoing the IconButton idea using the scale link icon.

Source/Engine/UI/GUI/Common/IconButton.cs

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+// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
+
+using System;
+
+namespace FlaxEngine.GUI
+{
+    /// <summary>
+    /// Button with an icon.
+    /// </summary>
+    public class IconButton : Button
+    {
+        /// <inheritdoc />
+        public override void ClearState()
+        {
+            base.ClearState();
+            
+            if (_isPressed)
+                OnPressEnd();
+        }
+
+        /// <inheritdoc />
+        public override void DrawSelf()
+        {
+            // Cache data
+            Rectangle clientRect = new Rectangle(Float2.Zero, Size);
+            bool enabled = EnabledInHierarchy;
+            Color backgroundColor = BackgroundColor;
+            Color borderColor = BorderColor;
+            Color textColor = TextColor;
+            if (!enabled)
+            {
+                backgroundColor *= 0.5f;
+                borderColor *= 0.5f;
+                textColor *= 0.6f;
+            }
+            else if (_isPressed)
+            {
+                backgroundColor = BackgroundColorSelected;
+                borderColor = BorderColorSelected;
+            }
+            else if (IsMouseOver || IsNavFocused)
+            {
+                backgroundColor = BackgroundColorHighlighted;
+                borderColor = BorderColorHighlighted;
+            }
+
+            // Draw background
+            if (BackgroundBrush != null)
+                BackgroundBrush.Draw(clientRect, backgroundColor);
+            else
+                Render2D.FillRectangle(clientRect, backgroundColor);
+            Render2D.DrawRectangle(clientRect, borderColor);
+
+            // Draw text
+            Render2D.DrawText(_font?.GetFont(), TextMaterial, _text, clientRect, textColor, TextAlignment.Center, TextAlignment.Center);
+        }
+
+        /// <inheritdoc />
+        public override void OnMouseEnter(Float2 location)
+        {
+            base.OnMouseEnter(location);
+
+            HoverBegin?.Invoke();
+        }
+
+        /// <inheritdoc />
+        public override void OnMouseLeave()
+        {
+            if (_isPressed)
+            {
+                OnPressEnd();
+            }
+
+            HoverEnd?.Invoke();
+
+            base.OnMouseLeave();
+        }
+
+        /// <inheritdoc />
+        public override bool OnMouseDown(Float2 location, MouseButton button)
+        {
+            if (base.OnMouseDown(location, button))
+                return true;
+
+            if (button == MouseButton.Left && !_isPressed)
+            {
+                OnPressBegin();
+                return true;
+            }
+            return false;
+        }
+
+        /// <inheritdoc />
+        public override bool OnMouseUp(Float2 location, MouseButton button)
+        {
+            if (base.OnMouseUp(location, button))
+                return true;
+
+            if (button == MouseButton.Left && _isPressed)
+            {
+                OnPressEnd();
+                OnClick();
+                return true;
+            }
+            return false;
+        }
+
+        /// <inheritdoc />
+        public override bool OnTouchDown(Float2 location, int pointerId)
+        {
+            if (base.OnTouchDown(location, pointerId))
+                return true;
+
+            if (!_isPressed)
+            {
+                OnPressBegin();
+                return true;
+            }
+            return false;
+        }
+
+        /// <inheritdoc />
+        public override bool OnTouchUp(Float2 location, int pointerId)
+        {
+            if (base.OnTouchUp(location, pointerId))
+                return true;
+
+            if (_isPressed)
+            {
+                OnPressEnd();
+                OnClick();
+                return true;
+            }
+            return false;
+        }
+
+        /// <inheritdoc />
+        public override void OnTouchLeave()
+        {
+            if (_isPressed)
+            {
+                OnPressEnd();
+            }
+
+            base.OnTouchLeave();
+        }
+
+        /// <inheritdoc />
+        public override void OnLostFocus()
+        {
+            if (_isPressed)
+            {
+                OnPressEnd();
+            }
+
+            base.OnLostFocus();
+        }
+
+        /// <inheritdoc />
+        public override void OnSubmit()
+        {
+            OnClick();
+
+            base.OnSubmit();
+        }
+    }
+}