fix/interface-scale

Source/Editor/Options/OptionsModule.cs

@@ -129,10 +129,13 @@ namespace FlaxEditor.Options
 
                     float prevInterfaceScale = Options.Interface.InterfaceScale;
                     Options = options;
-                    OnOptionsChanged();
 
-                    // Scale interface relative to the current value (eg. when using system-provided Dpi Scale)
+                    // Scale interface relative to the current value (eg. when using system-provided Dpi Scale).
+                    // Apply this before OnOptionsChanged so newly created fonts get rasterized at the target DPI scale (avoids blurry text).
                     Platform.CustomDpiScale *= Options.Interface.InterfaceScale / prevInterfaceScale;
+                    Font.SetGlobalScale(Platform.DpiScale);
+
+                    OnOptionsChanged();
                 }
                 else
                 {

Source/Engine/Render2D/Font.cpp

@@ -3,12 +3,30 @@
 #include "Font.h"
 #include "FontAsset.h"
 #include "FontManager.h"
+#include "Engine/Content/Content.h"
 #include "Engine/Core/Log.h"
 #include "Engine/Threading/Threading.h"
 #include "IncludeFreeType.h"
 
 Array<AssetReference<FontAsset>, HeapAllocation> Font::FallbackFonts;
 
+float Font::GetGlobalScale()
+{
+    return FontManager::FontScale;
+}
+
+void Font::SetGlobalScale(float scale)
+{
+    if (scale <= 0.0f || Math::NearEqual(FontManager::FontScale, scale)) return;
+    FontManager::FontScale = scale;
+
+    // Invalidate all loaded font assets so cached glyphs are re-rasterized and Font metrics are recomputed at the new scale
+    auto assets = Content::GetAssets<FontAsset>();
+    for (auto* asset : assets) if (asset) asset->Invalidate();
+
+    FontManager::Flush();
+}
+
 Font::Font(FontAsset* parentAsset, float size)
     : ManagedScriptingObject(SpawnParams(Guid::New(), Font::TypeInitializer))
     , _asset(parentAsset)

Source/Engine/Render2D/Font.h

@@ -261,6 +261,18 @@ public:
     /// </summary>
     API_FIELD() static Array<AssetReference<FontAsset>, HeapAllocation> FallbackFonts;
 
+    /// <summary>
+    /// Gets the global font scaling factor used to rasterize font glyphs at higher resolutions (eg. for high-DPI displays or UI scaling).
+    /// </summary>
+    API_PROPERTY() static float GetGlobalScale();
+
+    /// <summary>
+    /// Sets the global font scaling factor used to rasterize font glyphs at higher resolutions (eg. for high-DPI displays or UI scaling).
+    /// Calling this rebuilds the cached glyphs and metrics of every loaded font so text rendered afterwards stays crisp at the new scale.
+    /// </summary>
+    /// <param name="scale">The new font scale (must be greater than 0).</param>
+    API_FUNCTION() static void SetGlobalScale(float scale);
+
     /// <summary>
     /// Gets parent font asset that contains font family used by this font.
     /// </summary>