Fixed a "choose" line thickness issue.

Mac actually draws a line of zero width.

README.md

@@ -7,6 +7,8 @@ so the equations are rendered exactly as LaTeX would render them.
 `
 SwiftMath` is a Swift translation of the latest `iosMath` v0.9.5 release but includes bug fixes
 and enhancements like a new \lbar (lambda bar) character and cyrillic alphabet support.
+The original `iosMath` test suites have also been translated to Swift and run without errors.
+Note: Error test conditions are ignored to avoid tagging everything with silly `throw`s.
 Please let me know of any bugs or bug fixes that you find. 
 
 `SwiftMath` prepackages everything needed for direct access via the Swift Package Manager.

Sources/SwiftMath/MathRender/MTMathListDisplay.swift

@@ -369,11 +369,14 @@ class MTFractionDisplay : MTDisplay {
         self.textColor?.setStroke()
         
         // draw the horizontal line
-        let path = MTBezierPath()
-        path.move(to: CGPointMake(self.position.x, self.position.y + self.linePosition))
-        path.addLine(to: CGPointMake(self.position.x + self.width, self.position.y + self.linePosition))
-        path.lineWidth = self.lineThickness
-        path.stroke()
+        // Note: line thickness of 0 draws the thinnest possible line - we want no line so check for 0s
+        if self.lineThickness > 0 {
+            let path = MTBezierPath()
+            path.move(to: CGPointMake(self.position.x, self.position.y + self.linePosition))
+            path.addLine(to: CGPointMake(self.position.x + self.width, self.position.y + self.linePosition))
+            path.lineWidth = self.lineThickness
+            path.stroke()
+        }
         
         context.restoreGState()
     }

Sources/SwiftMath/MathRender/MTTypesetter.swift

@@ -962,7 +962,7 @@ class MTTypesetter {
         var numeratorShiftUp = self.numeratorShiftUp(frac!.hasRule)
         var denominatorShiftDown = self.denominatorShiftDown(frac!.hasRule)
         let barLocation = styleFont.mathTable!.axisHeight
-        let barThickness = frac!.hasRule ? styleFont.mathTable!.fractionRuleThickness : 0;
+        let barThickness = frac!.hasRule ? styleFont.mathTable!.fractionRuleThickness : 0
         
         if frac!.hasRule {
             // This is the difference between the lowest edge of the numerator and the top edge of the fraction bar