Add support for decoding Apple native font via factory

Expands on the current iOS factory method to decode raw font data (from file) to adding a second font decoding function that can use a native Apple font (`UIFont` / `NSFont`). This reuses some of the logic from fallback fonts. There's one main difference - while we are calculating weight and width, those get ignored in addition to size; the font data returned seems to be used as vector(?) data to draw characters in the weight / width as defined in a text run, rather than overridden by any supplied font. But, we need to provide a weight and width when obtaining a Rive font from cpp, so we re-use the logic.

Diffs=
414c142f2 Add support for decoding Apple native font via factory (#8180)

Co-authored-by: David Skuza <david@rive.app>

.rive_head

@@ -1 +1 @@
-48212b2bbd1f55028502f0669ea2be69c7a62694
+414c142f2c11ef3ad2cfa9fd0a1ed18dc7f9f98f

Source/Renderer/RiveFactory.mm

@@ -19,27 +19,30 @@
 
 static NSArray<id<RiveFallbackFontProvider>>* _fallbackFonts = nil;
 
-static rive::rcp<rive::Font> findFallbackFont(rive::Span<const rive::Unichar> missing)
+static rive::rcp<rive::Font> riveFontFromNativeFont(id font)
 {
-    // For each descriptor…
-    for (id<RiveFallbackFontProvider> fallback in RiveFont.fallbackFonts)
+    uint16_t weight = 400;
+    if ([font conformsToProtocol:@protocol(RiveWeightProvider)])
     {
-        id fallbackFont = fallback.fallbackFont;
+        weight = [font riveWeightValue];
+    }
 
-        uint16_t weight = 400;
-        if ([fallbackFont conformsToProtocol:@protocol(RiveWeightProvider)])
-        {
-            weight = [fallbackFont riveWeightValue];
-        }
+    uint8_t width = 100;
+    if ([font conformsToProtocol:@protocol(RiveFontWidthProvider)])
+    {
+        width = [font riveFontWidthValue];
+    }
 
-        uint8_t width = 100;
-        if ([fallbackFont conformsToProtocol:@protocol(RiveFontWidthProvider)])
-        {
-            width = [fallbackFont riveFontWidthValue];
-        }
+    CTFontRef ctFont = (__bridge CTFontRef)font;
+    return HBFont::FromSystem((void*)ctFont, weight, width);
+}
 
-        CTFontRef ctFont = (__bridge CTFontRef)fallbackFont;
-        auto font = HBFont::FromSystem((void*)ctFont, weight, width);
+static rive::rcp<rive::Font> findFallbackFont(rive::Span<const rive::Unichar> missing)
+{
+    // For each descriptor…
+    for (id<RiveFallbackFontProvider> fallback in RiveFont.fallbackFonts)
+    {
+        auto font = riveFontFromNativeFont(fallback.fallbackFont);
         if (font->hasGlyph(missing))
         {
             rive::rcp<rive::Font> rcFont = rive::rcp<rive::Font>(font);
@@ -181,6 +184,18 @@ - (RiveFont*)decodeFont:(nonnull NSData*)data
         initWithFont:instance->decodeFont(rive::Span<const uint8_t>(bytes, [data length]))];
 }
 
+#if TARGET_OS_IPHONE
+- (RiveFont*)decodeUIFont:(UIFont*)font
+{
+    return [[RiveFont alloc] initWithFont:riveFontFromNativeFont(font)];
+}
+#else
+- (RiveFont*)decodeNSFont:(NSFont*)font
+{
+    return [[RiveFont alloc] initWithFont:riveFontFromNativeFont(font)];
+}
+#endif
+
 - (RiveAudio*)decodeAudio:(nonnull NSData*)data
 {
     UInt8* bytes = (UInt8*)[data bytes];

Source/Renderer/include/RiveFactory.h

@@ -40,6 +40,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @interface RiveFactory : NSObject
 - (RiveFont*)decodeFont:(NSData*)data;
+#if TARGET_OS_IPHONE
+- (RiveFont*)decodeUIFont:(UIFont*)data NS_SWIFT_NAME(decodeFont(_:));
+#else
+- (RiveFont*)decodeNSFont:(NSFont*)data NS_SWIFT_NAME(decodeFont(_:));
+#endif
 - (RiveRenderImage*)decodeImage:(NSData*)data;
 - (RiveAudio*)decodeAudio:(NSData*)data;
 @end