Add inverted corners for negative values

Author: Oleg

Source/Charts/Data/Implementations/Standard/BarChartDataSet.swift

@@ -55,7 +55,29 @@ open class BarChartDataSet: BarLineScatterCandleBubbleChartDataSet, BarChartData
     public var cornerRadius: CGFloat = 0.0
 
     /// array of corners to be rounded
-    open var roundedCorners: UIRectCorner = []
+    open var roundedCorners: UIRectCorner = [] {
+        didSet {
+            var invertedCorners: UIRectCorner = []
+            if roundedCorners.contains(.topLeft) {
+                invertedCorners.insert(.bottomLeft)
+            }
+            if roundedCorners.contains(.topRight) {
+                invertedCorners.insert(.bottomRight)
+            }
+            if roundedCorners.contains(.bottomLeft) {
+                invertedCorners.insert(.topLeft)
+            }
+            if roundedCorners.contains(.bottomRight) {
+                invertedCorners.insert(.topRight)
+            }
+            if roundedCorners.contains(.allCorners) {
+                invertedCorners.insert(.allCorners)
+            }
+            roundedCornersInverted = invertedCorners
+        }
+    }
+    
+    open var roundedCornersInverted: UIRectCorner = []
 
     /// Calculates the total number of entries this DataSet represents, including
     /// stacks. All values belonging to a stack are calculated separately.

Source/Charts/Data/Interfaces/BarChartDataSetProtocol.swift

@@ -49,4 +49,7 @@ public protocol BarChartDataSetProtocol: BarLineScatterCandleBubbleChartDataSetP
 
     /// array of corners to be rounded
     var roundedCorners: UIRectCorner { get set }
+    
+    /// array of corners to be rounded
+    var roundedCornersInverted: UIRectCorner { get }
 }

Source/Charts/Renderers/BarChartRenderer.swift

@@ -352,7 +352,13 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
 
                 context.setFillColor(dataSet.barShadowColor.cgColor)
 
-                let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: dataSet.roundedCorners,
+                var roundedCorners = dataSet.roundedCorners
+                if let i = buffer.firstIndex(of: barRect),
+                   let entry = dataSet.entryForIndex(i),
+                   entry.y < 0 {
+                    roundedCorners = dataSet.roundedCornersInverted
+                }
+                let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: roundedCorners,
                                               cornerRadii: .init(width: dataSet.cornerRadius, height: dataSet.cornerRadius))
                 context.addPath(bezierPath.cgPath)
                 context.drawPath(using: .fill)
@@ -383,7 +389,12 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
                 context.setFillColor(dataSet.color(atIndex: j).cgColor)
             }
 
-            let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: dataSet.roundedCorners,
+            var roundedCorners = dataSet.roundedCorners
+            if let entry = dataSet.entryForIndex(j),
+               entry.y < 0 {
+                roundedCorners = dataSet.roundedCornersInverted
+            }
+            let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: roundedCorners,
                                           cornerRadii: .init(width: dataSet.cornerRadius, height: dataSet.cornerRadius))
             context.addPath(bezierPath.cgPath)
             context.drawPath(using: .fill)
@@ -751,7 +762,11 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
 
                 setHighlightDrawPos(highlight: high, barRect: barRect)
 
-                let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: set.roundedCorners,
+                var roundedCorners = set.roundedCorners
+                if e.y < 0 {
+                    roundedCorners = set.roundedCornersInverted
+                }
+                let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: roundedCorners,
                                               cornerRadii: .init(width: set.cornerRadius, height: set.cornerRadius))
                 context.addPath(bezierPath.cgPath)
                 context.drawPath(using: .fill)

Source/Charts/Renderers/HorizontalBarChartRenderer.swift

@@ -229,7 +229,11 @@ open class HorizontalBarChartRenderer: BarChartRenderer
 
                 context.setFillColor(dataSet.barShadowColor.cgColor)
 
-                let bezierPath = UIBezierPath(roundedRect: _barShadowRectBuffer, byRoundingCorners: dataSet.roundedCorners,
+                var roundedCorners = dataSet.roundedCorners
+                if _barShadowRectBuffer.minX < 0 {
+                    roundedCorners = dataSet.roundedCornersInverted
+                }
+                let bezierPath = UIBezierPath(roundedRect: _barShadowRectBuffer, byRoundingCorners: roundedCorners,
                                               cornerRadii: .init(width: dataSet.cornerRadius, height: dataSet.cornerRadius))
                 context.addPath(bezierPath.cgPath)
                 context.drawPath(using: .fill)
@@ -269,7 +273,11 @@ open class HorizontalBarChartRenderer: BarChartRenderer
                 context.setFillColor(dataSet.color(atIndex: j).cgColor)
             }
 
-            let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: dataSet.roundedCorners,
+            var roundedCorners = dataSet.roundedCorners
+            if barRect.minX < 0 {
+                roundedCorners = dataSet.roundedCornersInverted
+            }
+            let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: roundedCorners,
                                           cornerRadii: .init(width: dataSet.cornerRadius, height: dataSet.cornerRadius))
             context.addPath(bezierPath.cgPath)
             context.drawPath(using: .fill)