Fix #335: Parse generic fonts from svg

Source/platform/iOS/Common_iOS.swift

@@ -77,6 +77,10 @@ extension MFont {
     class var mSystemFontSize: CGFloat {
         return UIFont.systemFontSize
     }
+
+    class var mFamilyNames: [String] {
+        return UIFont.familyNames
+    }
 }
 
 extension UIScreen {

Source/platform/macOS/Common_macOS.swift

@@ -92,6 +92,10 @@ extension NSFont {
     class var mSystemFontSize: CGFloat {
         return NSFont.systemFontSize
     }
+
+    class var mFamilyNames: [String] {
+        return NSFontManager.shared.availableFontFamilies
+    }
 }
 
 extension NSScreen {

Source/render/RenderUtils.swift

@@ -90,26 +90,28 @@ class RenderUtils {
         fatalError("Unsupported node: \(node)")
     }
 
+    static let availableFonts = MFont.mFamilyNames.map{ $0.lowercased() }
+
     class func loadFont(name: String, size: Int) -> MFont? {
-        let separationSet = CharacterSet(charactersIn: ",")
-        let names = name.components(separatedBy: separationSet)
-        var customFont: MFont? = .none
-        names.forEach { fontName in
-            if customFont != .none {
-                return
+
+        let fontPriorities = name.split(separator: ",").map{ String($0).trimmingCharacters(in: CharacterSet(charactersIn: " '")).lowercased() }
+        for font in fontPriorities {
+            if availableFonts.contains(font) {
+                return MFont(name: font, size: CGFloat(size))
             }
-
-            if fontName.first == " " {
-                let index = fontName.index(fontName.startIndex, offsetBy: 1)
-                let fixedName = String(fontName.suffix(from: index))
-                customFont = MFont(name: fixedName, size: CGFloat(size))
-                return
+
+            if font == "serif" {
+                return MFont(name: "Georgia", size: CGFloat(size))
+            }
+            if font == "sans-serif" {
+                return MFont(name: "Arial", size: CGFloat(size))
+            }
+            if font == "monospace" {
+                return MFont(name: "Courier", size: CGFloat(size))
             }
-
-            customFont = MFont(name: fontName, size: CGFloat(size))
         }
 
-        return customFont
+        return .none
     }
 
     class func applyOpacity(_ color: Color, opacity: Double) -> Color {

Source/render/TextRenderer.swift

@@ -79,18 +79,18 @@ class TextRenderer: NodeRenderer {
         guard let text = text else {
             return MFont.systemFont(ofSize: 18.0)
         }
-
-        if let textFont = text.font {
-            if let customFont = RenderUtils.loadFont(name: textFont.name, size: textFont.size) {
-                return customFont
-            } else {
-                if let weight = getWeight(textFont.weight) {
-                    return MFont.systemFont(ofSize: CGFloat(textFont.size), weight: weight)
-                }
-                return MFont.systemFont(ofSize: CGFloat(textFont.size))
+        guard let textFont = text.font else {
+            return MFont.systemFont(ofSize: MFont.mSystemFontSize)
+        }
+
+        if let customFont = RenderUtils.loadFont(name: textFont.name, size: textFont.size) {
+            return customFont
+        } else {
+            if let weight = getWeight(textFont.weight) {
+                return MFont.systemFont(ofSize: CGFloat(textFont.size), weight: weight)
             }
+            return MFont.systemFont(ofSize: CGFloat(textFont.size))
         }
-        return MFont.systemFont(ofSize: MFont.mSystemFontSize)
     }
 
     fileprivate func getWeight(_ weight: String) -> MFont.Weight? {

Source/svg/SVGParser.swift

@@ -1268,7 +1268,7 @@ open class SVGParser {
     }
 
     fileprivate func getFontName(_ attributes: [String: String]) -> String? {
-        return attributes["font-family"]
+        return attributes["font-family"]?.trimmingCharacters(in: .whitespacesAndNewlines)
     }
 
     fileprivate func getFontSize(_ attributes: [String: String]) -> Int? {