Fix #473 and #474: custom fonts are not loaded correctly

Source/animation/AnimationProducer.swift

@@ -349,7 +349,7 @@ class AnimationContext {
     var rootTransform: Transform?
 
     func getLayoutTransform(_ renderer: NodeRenderer?) -> Transform {
-        if (rootTransform == nil) {
+        if rootTransform == nil {
             if let view = renderer?.view, let node = view.renderer?.node() {
                 rootTransform = LayoutHelper.calcTransform(node, view.contentLayout, view.bounds.size.toMacaw())
             }

Source/platform/iOS/Common_iOS.swift

@@ -86,6 +86,10 @@ extension MFont {
     class var mFamilyNames: [String] {
         return UIFont.familyNames
     }
+
+    class func mFontNames(forFamily: String) -> [String] {
+        return UIFont.fontNames(forFamilyName: forFamily)
+    }
 }
 
 extension UIScreen {

Source/platform/macOS/Common_macOS.swift

@@ -101,6 +101,17 @@ extension NSFont {
     class var mFamilyNames: [String] {
         return NSFontManager.shared.availableFontFamilies
     }
+
+    class func mFontNames(forFamily: String) -> [String] {
+        var result = [String]()
+        if let members = NSFontManager.shared.availableMembers(ofFontFamily: forFamily) {
+            for member in members {
+                result.append(member[0] as! String)
+            }
+        }
+        return result
+    }
+
 }
 
 extension NSScreen {

Source/render/RenderUtils.swift

@@ -33,36 +33,30 @@ class RenderUtils {
         fatalError("Unsupported node: \(node)")
     }
 
-    static let availableFonts = MFont.mFamilyNames.map { $0.lowercased() }
-
-    class func loadFont(name: String, size: Int, weight: String?) -> MFont? {
-
-        var fontName = ""
-        let fontPriorities = name.split(separator: ",").map { String($0).trimmingCharacters(in: CharacterSet(charactersIn: " '")) }
-
-        for font in fontPriorities {
-            let lowercasedFont = font.lowercased()
-
-            if availableFonts.contains(lowercasedFont) {
-                fontName = font
-            }
-
-            if lowercasedFont == "serif" {
-                fontName = "Georgia"
-            }
-            if lowercasedFont == "sans-serif" {
-                fontName = "Arial"
-            }
-            if lowercasedFont == "monospace" {
-                fontName = "Courier"
+    static let availableFonts = prepareFonts()
+
+    static func prepareFonts() -> [String: String] {
+        var result = [String: String]()
+        for family in MFont.mFamilyNames {
+            // TODO: do we need to include family names?
+            result[family.lowercased()] = family
+            for font in MFont.mFontNames(forFamily: family) {
+                result[font.lowercased()] = font
             }
         }
-        if fontName.isEmpty {
-            return .none
-        }
+        result["serif"] = "Georgia"
+        result["sans-serif"] = "Arial"
+        result["monospace"] = "Courier"
+        return result
+    }
 
+    class func loadFont(name: String, size: Int, weight: String?) -> MFont? {
+        guard let fontName = findFontName(title: name) else {
+            return nil
+        }
         var fontDesc = MFontDescriptor(name: fontName, size: CGFloat(size))
-        if weight == "bold" || weight == "bolder" {
+        let lowerWeight = weight?.lowercased()
+        if lowerWeight == "bold" || lowerWeight == "bolder" {
             #if os(iOS)
             fontDesc = fontDesc.withSymbolicTraits(.traitBold)!
             #elseif os(OSX)
@@ -73,6 +67,16 @@ class RenderUtils {
         return MFont(descriptor: fontDesc, size: CGFloat(size))
     }
 
+    static func findFontName(title: String) -> String? {
+        let fonts = title.split(separator: ",").map { String($0).trimmingCharacters(in: CharacterSet(charactersIn: " '")) }
+        for font in fonts {
+            if let availableFont = availableFonts[font.lowercased()] {
+                return availableFont
+            }
+        }
+        return nil
+    }
+
     class func applyOpacity(_ color: Color, opacity: Double) -> Color {
         return Color.rgba(r: color.r(), g: color.g(), b: color.b(), a: Double(color.a()) / 255.0 * opacity)
     }