Add rounded corners on the bar chart #1066

ChartsDemo/Classes/DemoBaseViewController.m

@@ -143,6 +143,28 @@ - (void)handleOption:(NSString *)key forChartView:(ChartViewBase *)chartView
 
         [chartView setNeedsDisplay];
     }
+
+    if ([key isEqualToString:@"toggleRoundedBarsAllCorners"])
+    {
+        ((BarChartView *)chartView).drawRoundedBarEnabled = YES;
+
+        [chartView setNeedsDisplay];
+    }
+
+    if ([key isEqualToString:@"toggleRoundedBarsTopCorners"])
+    {
+        ((BarChartView *)chartView).drawRoundedBarEnabled = YES;
+
+        for (id<IBarChartDataSet, NSObject> set in chartView.data.dataSets)
+        {
+            if ([set conformsToProtocol:@protocol(IBarChartDataSet)])
+            {
+                set.barRoundingCorners = UIRectCornerTopLeft | UIRectCornerTopRight;
+            }
+        }
+
+        [chartView setNeedsDisplay];
+    }
 }
 
 #pragma mark - Actions

ChartsDemo/Classes/Demos/BarChartViewController.m

@@ -42,6 +42,8 @@ - (void)viewDidLoad
                      @{@"key": @"toggleAutoScaleMinMax", @"label": @"Toggle auto scale min/max"},
                      @{@"key": @"toggleData", @"label": @"Toggle Data"},
                      @{@"key": @"toggleBarBorders", @"label": @"Show Bar Borders"},
+                     @{@"key": @"toggleRoundedBarsAllCorners", @"label": @"All Corners Rounded"},
+                     @{@"key": @"toggleRoundedBarsTopCorners", @"label": @"Top Corners Rounded"},
                      ];
 
     [self setupBarLineChartView:_chartView];

Source/Charts/Charts/BarChartView.swift

@@ -21,6 +21,9 @@ open class BarChartView: BarLineChartViewBase, BarChartDataProvider
     /// if set to true, a grey area is drawn behind each bar that indicates the maximum value
     fileprivate var _drawBarShadowEnabled = false
 
+    /// if set to true, a rounded rectangle with the corners is drawn on each bar
+    fileprivate var _drawRoundedBarEnabled = false
+
     internal override func initialize()
     {
         super.initialize()
@@ -159,6 +162,17 @@ open class BarChartView: BarLineChartViewBase, BarChartDataProvider
             setNeedsDisplay()
         }
     }
+
+    /// if set to true, a rounded rectangle with the corners is drawn on each bar
+    open var drawRoundedBarEnabled: Bool
+        {
+        get { return _drawRoundedBarEnabled }
+        set
+        {
+            _drawRoundedBarEnabled = newValue
+            setNeedsDisplay()
+        }
+    }
 
     /// Adds half of the bar width to each side of the x-axis range in order to allow the bars of the barchart to be fully displayed.
     /// **default**: false
@@ -180,4 +194,7 @@ open class BarChartView: BarLineChartViewBase, BarChartDataProvider
 
     /// - returns: `true` if drawing shadows (maxvalue) for each bar is enabled, `false` ifnot
     open var isDrawBarShadowEnabled: Bool { return drawBarShadowEnabled }
+
+    /// - returns: `true` if drawing rounded bars is enabled, `false` ifnot
+    open var isDrawRoundedBarEnabled: Bool { return drawRoundedBarEnabled }
 }

Source/Charts/Charts/CombinedChartView.swift

@@ -195,6 +195,13 @@ open class CombinedChartView: BarLineChartViewBase, CombinedChartDataProvider
         get { return (renderer as! CombinedChartRenderer!).drawBarShadowEnabled }
         set { (renderer as! CombinedChartRenderer!).drawBarShadowEnabled = newValue }
     }
+
+    /// if set to true, a rounded rectangle with the corners is drawn on each bar
+    open var drawRoundedBarEnabled: Bool
+        {
+        get { return (renderer as! CombinedChartRenderer!).drawRoundedBarEnabled }
+        set { (renderer as! CombinedChartRenderer!).drawRoundedBarEnabled = newValue }
+    }
 
     /// - returns: `true` if drawing values above bars is enabled, `false` ifnot
     open var isDrawValueAboveBarEnabled: Bool { return (renderer as! CombinedChartRenderer!).drawValueAboveBarEnabled }
@@ -222,4 +229,7 @@ open class CombinedChartView: BarLineChartViewBase, CombinedChartDataProvider
 
     /// - returns: `true` the highlight is be full-bar oriented, `false` ifsingle-value
     open var isHighlightFullBarEnabled: Bool { return highlightFullBarEnabled }
+
+    /// - returns: `true` if drawing rounded bars is enabled, `false` ifnot
+    open var isDrawRoundedBarEnabled: Bool { return drawRoundedBarEnabled }
 }

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

@@ -146,6 +146,11 @@ open class BarChartDataSet: BarLineScatterCandleBubbleChartDataSet, IBarChartDat
     /// the color drawing borders around the bars.
     open var barBorderColor = NSUIColor.black
 
+    #if !os(OSX)
+    /// the option rounding bar corners
+    open var barRoundingCorners: UIRectCorner = .allCorners
+    #endif
+
     /// the alpha value (transparency) that is used for drawing the highlight indicator bar. min = 0.0 (fully transparent), max = 1.0 (fully opaque)
     open var highlightAlpha = CGFloat(120.0 / 255.0)
 

Source/Charts/Data/Interfaces/IBarChartDataSet.swift

@@ -34,6 +34,11 @@ public protocol IBarChartDataSet: IBarLineScatterCandleBubbleChartDataSet
     /// the color drawing borders around the bars.
     var barBorderColor: NSUIColor { get set }
 
+    #if !os(OSX)
+    /// the option rounding bar corners
+    var barRoundingCorners: UIRectCorner { get set }
+    #endif
+
     /// the alpha value (transparency) that is used for drawing the highlight indicator bar. min = 0.0 (fully transparent), max = 1.0 (fully opaque)
     var highlightAlpha: CGFloat { get set }
 

Source/Charts/Interfaces/BarChartDataProvider.swift

@@ -18,6 +18,7 @@ public protocol BarChartDataProvider: BarLineScatterCandleBubbleChartDataProvide
     var barData: BarChartData? { get }
 
     var isDrawBarShadowEnabled: Bool { get }
+    var isDrawRoundedBarEnabled: Bool { get }
     var isDrawValueAboveBarEnabled: Bool { get }
     var isHighlightFullBarEnabled: Bool { get }
-}
+}

Source/Charts/Renderers/BarChartRenderer.swift

@@ -310,14 +310,36 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
                 // Set the color for the currently drawn value. If the index is out of bounds, reuse colors.
                 context.setFillColor(dataSet.color(atIndex: j).cgColor)
             }
-
-            context.fill(barRect)
-
-            if drawBorder
+
+            if dataProvider.isDrawRoundedBarEnabled
             {
-                context.setStrokeColor(borderColor.cgColor)
-                context.setLineWidth(borderWidth)
-                context.stroke(barRect)
+                let cornerRadius = CGSize(width: barRect.width / 2.0, height: barRect.width / 2.0)
+                #if os(OSX)
+                    let bezierPath = NSBezierPath(roundedRect: barRect, xRadius: cornerRadius.width, yRadius: cornerRadius.height)
+                    context.addPath(bezierPath.cgPath)
+                #else
+                    let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: dataSet.barRoundingCorners, cornerRadii: cornerRadius)
+                    context.addPath(bezierPath.cgPath)
+                #endif
+                context.fillPath()
+
+                if drawBorder
+                {
+                    bezierPath.lineWidth = borderWidth
+                    borderColor.setStroke()
+                    bezierPath.stroke()
+                }
+            }
+            else
+            {
+                context.fill(barRect)
+
+                if drawBorder
+                {
+                    context.setStrokeColor(borderColor.cgColor)
+                    context.setLineWidth(borderWidth)
+                    context.stroke(barRect)
+                }
             }
         }
 
@@ -574,7 +596,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
                 let set = barData.getDataSetByIndex(high.dataSetIndex) as? IBarChartDataSet,
                 set.isHighlightEnabled
                 else { continue }
-            
+
             if let e = set.entryForXValue(high.x, closestToY: high.y) as? BarChartDataEntry
             {
                 if !isInBoundsX(entry: e, dataSet: set)
@@ -617,7 +639,22 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
 
                 setHighlightDrawPos(highlight: high, barRect: barRect)
 
-                context.fill(barRect)
+                if dataProvider.isDrawRoundedBarEnabled
+                {
+                    let cornerRadius = CGSize(width: barRect.width / 2.0, height: barRect.width / 2.0)
+                    #if os(OSX)
+                        let bezierPath = NSBezierPath(roundedRect: barRect, xRadius: cornerRadius.width, yRadius: cornerRadius.height)
+                        context.addPath(bezierPath.cgPath)
+                    #else
+                        let bezierPath = UIBezierPath(roundedRect: barRect, byRoundingCorners: set.barRoundingCorners, cornerRadii: cornerRadius)
+                        context.addPath(bezierPath.cgPath)
+                    #endif
+                    context.fillPath()
+                }
+                else
+                {
+                    context.fill(barRect)
+                }
             }
         }
 

Source/Charts/Renderers/CombinedChartRenderer.swift

@@ -22,6 +22,9 @@ open class CombinedChartRenderer: DataRenderer
     /// if set to true, a grey area is drawn behind each bar that indicates the maximum value
     open var drawBarShadowEnabled = false
 
+    /// if set to true, a rounded rectangle with the corners is drawn on each bar
+    open var drawRoundedBarEnabled = false
+
     internal var _renderers = [DataRenderer]()
 
     internal var _drawOrder: [CombinedChartView.DrawOrder] = [.bar, .bubble, .line, .candle, .scatter]

Source/Charts/Utils/Platform.swift

@@ -515,6 +515,54 @@ types are aliased to either their UI* implementation (on iOS) or their NS* imple
             }
 		}
     }
+
+    extension NSBezierPath
+    {
+        var cgPath: CGPath
+        {
+            let mutablePath = CGMutablePath()
+            var points = [CGPoint](repeating: .zero, count: 3)
+            for i in 0 ..< elementCount
+            {
+                let type = element(at: i, associatedPoints: &points)
+                switch type
+                {
+                case .moveToBezierPathElement:
+                    mutablePath.move(
+                        to: CGPoint(
+                            x: points[0].x,
+                            y: points[0].y
+                        )
+                    )
+                case .lineToBezierPathElement:
+                    mutablePath.addLine(
+                        to: CGPoint(
+                            x: points[0].x,
+                            y: points[0].y
+                        )
+                    )
+                case .curveToBezierPathElement:
+                    mutablePath.addCurve(
+                        to: CGPoint(
+                            x: points[2].x,
+                            y: points[2].y
+                        ),
+                        control1: CGPoint(
+                            x: points[0].x,
+                            y: points[0].y
+                        ),
+                        control2: CGPoint(
+                            x: points[1].x,
+                            y: points[1].y
+                        )
+                    )
+                case .closePathBezierPathElement:
+                    mutablePath.closeSubpath()
+                }
+            }
+            return mutablePath
+        }
+    }
 
     extension NSString
     {

Source/ChartsRealm/Data/RealmBarDataSet.swift

@@ -214,6 +214,11 @@ open class RealmBarDataSet: RealmBarLineScatterCandleBubbleDataSet, IBarChartDat
     /// the color drawing borders around the bars.
     open var barBorderColor = NSUIColor(red: 0.0/255.0, green: 0.0/255.0, blue: 0.0/255.0, alpha: 1.0)
 
+    #if !os(OSX)
+    /// the option rounding bar corners
+    open var barRoundingCorners: UIRectCorner = .allCorners
+    #endif
+
     /// the alpha value (transparency) that is used for drawing the highlight indicator bar. min = 0.0 (fully transparent), max = 1.0 (fully opaque)
     open var highlightAlpha = CGFloat(120.0 / 255.0)