Add fallback settings for control

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

@@ -182,6 +182,12 @@ namespace FlaxEngine.GUI
             set => _autoFitTextRange = value;
         }
 
+        /// <summary>
+        /// Gets or sets whether to fallback when the primary font cannot render a char.
+        /// </summary>
+        [EditorOrder(120), DefaultValue(true), Tooltip("Whether to fallback when the font cannot render a char.")]
+        public bool EnableFontFallback { get; set; } = true;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Label"/> class.
         /// </summary>
@@ -233,7 +239,23 @@ namespace FlaxEngine.GUI
                 }
             }
 
-            Render2D.DrawText(_font.GetFont(), Material, _text, rect, color, hAlignment, wAlignment, Wrapping, BaseLinesGapScale, scale);
+            if (EnableFontFallback)
+            {
+                Render2D.DrawText(_font.GetFont(), Material, _text, rect, color, hAlignment, wAlignment, Wrapping, BaseLinesGapScale, scale);
+            }
+            else
+            {
+                var layout = new TextLayoutOptions
+                {
+                    Bounds = rect,
+                    HorizontalAlignment = hAlignment,
+                    VerticalAlignment = wAlignment,
+                    TextWrapping = Wrapping,
+                    Scale = scale,
+                    BaseLinesGapScale = BaseLinesGapScale,
+                };
+                Render2D.DrawTextInternal(_font.GetFont(), _text, color, ref layout, Material);
+            }
 
             if (ClipText)
                 Render2D.PopClip();
@@ -254,7 +276,8 @@ namespace FlaxEngine.GUI
                         layout.Bounds.Size.X = Width - Margin.Width;
                     else if (_autoWidth && !_autoHeight)
                         layout.Bounds.Size.Y = Height - Margin.Height;
-                    _textSize = font.MeasureText(_text, ref layout);
+                    _textSize = EnableFontFallback ?
+                        font.MeasureText(_text, ref layout) : font.MeasureTextInternal(_text, ref layout);
                     _textSize.Y *= BaseLinesGapScale;
 
                     // Check if size is controlled via text

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

@@ -1,6 +1,8 @@
 // Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
 
 
+using System.ComponentModel;
+
 namespace FlaxEngine.GUI
 {
     /// <summary>
@@ -65,6 +67,12 @@ namespace FlaxEngine.GUI
         [EditorDisplay("Text Style"), EditorOrder(2022), Tooltip("The color of the selection (Transparent if not used).")]
         public Color SelectionColor { get; set; }
 
+        /// <summary>
+        /// Gets or sets whether to fallback when the primary font cannot render a char.
+        /// </summary>
+        [EditorOrder(120), DefaultValue(true), Tooltip("Whether to fallback when the font cannot render a char.")]
+        public bool EnableFontFallback { get; set; } = true;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="TextBox"/> class.
         /// </summary>
@@ -104,7 +112,8 @@ namespace FlaxEngine.GUI
                 return Float2.Zero;
             }
 
-            return font.MeasureText(_text, ref _layout);
+            return EnableFontFallback ? font.MeasureText(_text, ref _layout) :
+                font.MeasureTextInternal(_text, ref _layout);
         }
 
         /// <inheritdoc />
@@ -117,8 +126,9 @@ namespace FlaxEngine.GUI
                 return Float2.Zero;
             }
 
-            height = font.GetMaxHeight() / DpiScale;
+            height = (EnableFontFallback ? font.GetMaxHeight() : font.Height) / DpiScale;
-            return font.GetCharPosition(_text, index, ref _layout);
+            return EnableFontFallback ? font.GetCharPosition(_text, index, ref _layout) :
+                font.GetCharPositionInternal(_text, index, ref _layout);
         }
 
         /// <inheritdoc />
@@ -130,7 +140,8 @@ namespace FlaxEngine.GUI
                 return 0;
             }
 
-            return font.HitTestText(_text, location, ref _layout);
+            return EnableFontFallback ? font.HitTestText(_text, location, ref _layout) :
+                font.HitTestTextInternal(_text, location, ref _layout);
         }
 
         /// <inheritdoc />
@@ -169,8 +180,12 @@ namespace FlaxEngine.GUI
             // Check if sth is selected to draw selection
             if (HasSelection)
             {
-                var leftEdge = font.GetCharPosition(_text, SelectionLeft, ref _layout);
+                var leftEdge = EnableFontFallback ?
-                var rightEdge = font.GetCharPosition(_text, SelectionRight, ref _layout);
+                    font.GetCharPosition(_text, SelectionLeft, ref _layout) :
+                    font.GetCharPositionInternal(_text, SelectionLeft, ref _layout);
+                var rightEdge = EnableFontFallback ?
+                    font.GetCharPosition(_text, SelectionRight, ref _layout) :
+                    font.GetCharPositionInternal(_text, SelectionRight, ref _layout);
                 float fontHeight = font.GetMaxHeight() / DpiScale;
 
                 // Draw selection background
@@ -211,11 +226,19 @@ namespace FlaxEngine.GUI
                 var color = TextColor;
                 if (!enabled)
                     color *= 0.6f;
-                Render2D.DrawText(font, _text, color, ref _layout, TextMaterial);
+                if (EnableFontFallback)
+                    Render2D.DrawText(font, _text, color, ref _layout, TextMaterial);
+                else
+                    // Draw without fallback
+                    Render2D.DrawTextInternal(font, _text, color, ref _layout, TextMaterial);
             }
             else if (!string.IsNullOrEmpty(_watermarkText) && !IsFocused)
             {
-                Render2D.DrawText(font, _watermarkText, WatermarkTextColor, ref _layout, TextMaterial);
+                if (EnableFontFallback)
+                    Render2D.DrawText(font, _watermarkText, WatermarkTextColor, ref _layout, TextMaterial);
+                else
+                    // Draw without fallback
+                    Render2D.DrawTextInternal(font, _watermarkText, WatermarkTextColor, ref _layout, TextMaterial);
             }
 
             // Caret