Merge pull request #513 from danielgindi/x-axis-label-rotation

Implemented support for rotated labels on the x-axis (Resolves #61)

Charts/Classes/Charts/BarLineChartViewBase.swift

@@ -448,7 +448,7 @@ public class BarLineChartViewBase: ChartViewBase, BarLineScatterCandleBubbleChar
 
             if (xAxis.isEnabled && xAxis.isDrawLabelsEnabled)
             {
-                let xlabelheight = xAxis.labelHeight * 2.0
+                let xlabelheight = xAxis.labelRotatedHeight + xAxis.yOffset
 
                 // offsets for x-labels
                 if (xAxis.labelPosition == .Bottom)
@@ -493,7 +493,7 @@ public class BarLineChartViewBase: ChartViewBase, BarLineScatterCandleBubbleChar
 
         if (!_xAxis.isAxisModulusCustom)
         {
-            _xAxis.axisLabelModulus = Int(ceil((CGFloat(_data.xValCount) * _xAxis.labelWidth) / (_viewPortHandler.contentWidth * _viewPortHandler.touchMatrix.a)))
+            _xAxis.axisLabelModulus = Int(ceil((CGFloat(_data.xValCount) * _xAxis.labelRotatedWidth) / (_viewPortHandler.contentWidth * _viewPortHandler.touchMatrix.a)))
         }
 
         if (_xAxis.axisLabelModulus < 1)

Charts/Classes/Charts/HorizontalBarChartView.swift

@@ -87,7 +87,7 @@ public class HorizontalBarChartView: BarChartView
             offsetBottom += _rightAxis.getRequiredHeightSpace()
         }
 
-        let xlabelwidth = _xAxis.labelWidth
+        let xlabelwidth = _xAxis.labelRotatedWidth
 
         if (_xAxis.isEnabled)
         {
@@ -130,7 +130,7 @@ public class HorizontalBarChartView: BarChartView
 
     internal override func calcModulus()
     {
-        _xAxis.axisLabelModulus = Int(ceil((CGFloat(_data.xValCount) * _xAxis.labelHeight) / (_viewPortHandler.contentHeight * viewPortHandler.touchMatrix.d)))
+        _xAxis.axisLabelModulus = Int(ceil((CGFloat(_data.xValCount) * _xAxis.labelRotatedHeight) / (_viewPortHandler.contentHeight * viewPortHandler.touchMatrix.d)))
 
         if (_xAxis.axisLabelModulus < 1)
         {

Charts/Classes/Charts/PieRadarChartViewBase.swift

@@ -219,7 +219,7 @@ public class PieRadarChartViewBase: ChartViewBase
 
             if x.isEnabled && x.drawLabelsEnabled
             {
-                minOffset = max(minOffset, x.labelWidth)
+                minOffset = max(minOffset, x.labelRotatedWidth)
             }
         }
 

Charts/Classes/Charts/RadarChartView.swift

@@ -264,7 +264,7 @@ public class RadarChartView: PieRadarChartViewBase
 
     internal override var requiredBaseOffset: CGFloat
     {
-        return _xAxis.isEnabled && _xAxis.isDrawLabelsEnabled ? _xAxis.labelWidth : 10.0
+        return _xAxis.isEnabled && _xAxis.isDrawLabelsEnabled ? _xAxis.labelRotatedWidth : 10.0
     }
 
     public override var radius: CGFloat

Charts/Classes/Components/ChartXAxis.swift

@@ -28,9 +28,22 @@ public class ChartXAxis: ChartAxisBase
     }
 
     public var values = [String?]()
+
+    /// width of the x-axis labels in pixels - this is automatically calculated by the computeAxis() methods in the renderers
     public var labelWidth = CGFloat(1.0)
+
+    /// height of the x-axis labels in pixels - this is automatically calculated by the computeAxis() methods in the renderers
     public var labelHeight = CGFloat(1.0)
 
+    /// width of the (rotated) x-axis labels in pixels - this is automatically calculated by the computeAxis() methods in the renderers
+    public var labelRotatedWidth = CGFloat(1.0)
+
+    /// height of the (rotated) x-axis labels in pixels - this is automatically calculated by the computeAxis() methods in the renderers
+    public var labelRotatedHeight = CGFloat(1.0)
+
+    /// This is the angle for drawing the X axis labels (in degrees)
+    public var labelRotationAngle = CGFloat(0.0)
+
     /// the space that should be left out (in characters) between the x-axis labels
     /// This only applies if the number of labels that will be skipped in between drawn axis labels is not custom set.
     /// 
@@ -73,7 +86,7 @@ public class ChartXAxis: ChartAxisBase
     public var labelPosition = XAxisLabelPosition.Top
 
     /// if set to true, word wrapping the labels will be enabled.
-    /// word wrapping is done using `(value width * labelWidth)`
+    /// word wrapping is done using `(value width * labelRotatedWidth)`
     ///
     /// *Note: currently supports all charts except pie/radar/horizontal-bar*
     public var wordWrapEnabled = false
@@ -90,6 +103,8 @@ public class ChartXAxis: ChartAxisBase
     public override init()
     {
         super.init()
+
+        self.yOffset = 4.0;
     }
 
     public override func getLongestLabel() -> String

Charts/Classes/Renderers/ChartXAxisRenderer.swift

@@ -39,8 +39,18 @@ public class ChartXAxisRenderer: ChartAxisRendererBase
 
         let widthText = a as NSString
 
-        _xAxis.labelWidth = widthText.sizeWithAttributes([NSFontAttributeName: _xAxis.labelFont]).width
-        _xAxis.labelHeight = _xAxis.labelFont.lineHeight
+        let labelSize = widthText.sizeWithAttributes([NSFontAttributeName: _xAxis.labelFont])
+
+        let labelWidth = labelSize.width
+        let labelHeight = labelSize.height
+
+        let labelRotatedSize = ChartUtils.sizeOfRotatedRectangle(labelSize, degrees: _xAxis.labelRotationAngle)
+
+        _xAxis.labelWidth = labelWidth
+        _xAxis.labelHeight = labelHeight
+        _xAxis.labelRotatedWidth = labelRotatedSize.width
+        _xAxis.labelRotatedHeight = labelRotatedSize.height
+
         _xAxis.values = xValues
     }
 
@@ -51,28 +61,28 @@ public class ChartXAxisRenderer: ChartAxisRendererBase
             return
         }
 
-        let yoffset = CGFloat(4.0)
+        let yOffset = _xAxis.yOffset
 
         if (_xAxis.labelPosition == .Top)
         {
-            drawLabels(context: context, pos: viewPortHandler.offsetTop - _xAxis.labelHeight - yoffset)
+            drawLabels(context: context, pos: viewPortHandler.contentTop - yOffset, anchor: CGPoint(x: 0.5, y: 1.0))
         }
-        else if (_xAxis.labelPosition == .Bottom)
+        else if (_xAxis.labelPosition == .TopInside)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentBottom + yoffset * 1.5)
+            drawLabels(context: context, pos: viewPortHandler.contentTop + yOffset + _xAxis.labelRotatedHeight, anchor: CGPoint(x: 0.5, y: 1.0))
         }
-        else if (_xAxis.labelPosition == .BottomInside)
+        else if (_xAxis.labelPosition == .Bottom)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentBottom - _xAxis.labelHeight - yoffset)
+            drawLabels(context: context, pos: viewPortHandler.contentBottom + yOffset, anchor: CGPoint(x: 0.5, y: 0.0))
         }
-        else if (_xAxis.labelPosition == .TopInside)
+        else if (_xAxis.labelPosition == .BottomInside)
         {
-            drawLabels(context: context, pos: viewPortHandler.offsetTop + yoffset)
+            drawLabels(context: context, pos: viewPortHandler.contentBottom - yOffset - _xAxis.labelRotatedHeight, anchor: CGPoint(x: 0.5, y: 0.0))
         }
         else
         { // BOTH SIDED
-            drawLabels(context: context, pos: viewPortHandler.offsetTop - _xAxis.labelHeight - yoffset)
-            drawLabels(context: context, pos: viewPortHandler.contentBottom + yoffset * 1.6)
+            drawLabels(context: context, pos: viewPortHandler.contentTop - yOffset, anchor: CGPoint(x: 0.5, y: 1.0))
+            drawLabels(context: context, pos: viewPortHandler.contentBottom + yOffset, anchor: CGPoint(x: 0.5, y: 0.0))
         }
     }
 
@@ -124,14 +134,15 @@ public class ChartXAxisRenderer: ChartAxisRendererBase
     }
 
     /// draws the x-labels on the specified y-position
-    internal func drawLabels(context context: CGContext, pos: CGFloat)
+    internal func drawLabels(context context: CGContext, pos: CGFloat, anchor: CGPoint)
     {
         let paraStyle = NSParagraphStyle.defaultParagraphStyle().mutableCopy() as! NSMutableParagraphStyle
         paraStyle.alignment = .Center
 
         let labelAttrs = [NSFontAttributeName: _xAxis.labelFont,
             NSForegroundColorAttributeName: _xAxis.labelTextColor,
             NSParagraphStyleAttributeName: paraStyle]
+        let labelRotationAngleRadians = _xAxis.labelRotationAngle * ChartUtils.Math.FDEG2RAD
 
         let valueToPixelMatrix = transformer.valueToPixelMatrix
 
@@ -180,15 +191,15 @@ public class ChartXAxisRenderer: ChartAxisRendererBase
                     }
                 }
 
-                drawLabel(context: context, label: label!, xIndex: i, x: position.x, y: pos, align: .Center, attributes: labelAttrs, constrainedToSize: labelMaxSize)
+                drawLabel(context: context, label: label!, xIndex: i, x: position.x, y: pos, attributes: labelAttrs, constrainedToSize: labelMaxSize, anchor: anchor, angleRadians: labelRotationAngleRadians)
             }
         }
     }
 
-    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, align: NSTextAlignment, attributes: [String: NSObject], constrainedToSize: CGSize)
+    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, attributes: [String: NSObject], constrainedToSize: CGSize, anchor: CGPoint, angleRadians: CGFloat)
     {
         let formattedLabel = _xAxis.valueFormatter?.stringForXValue(xIndex, original: label, viewPortHandler: viewPortHandler) ?? label
-        ChartUtils.drawMultilineText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), align: align, attributes: attributes, constrainedToSize: constrainedToSize)
+        ChartUtils.drawMultilineText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), attributes: attributes, constrainedToSize: constrainedToSize, anchor: anchor, angleRadians: angleRadians)
     }
 
     private var _gridLineSegmentsBuffer = [CGPoint](count: 2, repeatedValue: CGPoint())

Charts/Classes/Renderers/ChartXAxisRendererBarChart.swift

@@ -27,7 +27,7 @@ public class ChartXAxisRendererBarChart: ChartXAxisRenderer
     }
 
     /// draws the x-labels on the specified y-position
-    internal override func drawLabels(context context: CGContext, pos: CGFloat)
+    internal override func drawLabels(context context: CGContext, pos: CGFloat, anchor: CGPoint)
     {
         if (_chart.data === nil)
         {
@@ -40,6 +40,7 @@ public class ChartXAxisRendererBarChart: ChartXAxisRenderer
         let labelAttrs = [NSFontAttributeName: _xAxis.labelFont,
             NSForegroundColorAttributeName: _xAxis.labelTextColor,
             NSParagraphStyleAttributeName: paraStyle]
+        let labelRotationAngleRadians = _xAxis.labelRotationAngle * ChartUtils.Math.FDEG2RAD
 
         let barData = _chart.data as! BarChartData
         let step = barData.dataSetCount
@@ -99,7 +100,7 @@ public class ChartXAxisRendererBarChart: ChartXAxisRenderer
                     }
                 }
 
-                drawLabel(context: context, label: label!, xIndex: i, x: position.x, y: pos, align: .Center, attributes: labelAttrs, constrainedToSize: labelMaxSize)
+                drawLabel(context: context, label: label!, xIndex: i, x: position.x, y: pos, attributes: labelAttrs, constrainedToSize: labelMaxSize, anchor: anchor, angleRadians: labelRotationAngleRadians)
             }
         }
     }

Charts/Classes/Renderers/ChartXAxisRendererHorizontalBarChart.swift

@@ -27,9 +27,18 @@ public class ChartXAxisRendererHorizontalBarChart: ChartXAxisRendererBarChart
         _xAxis.values = xValues
 
         let longest = _xAxis.getLongestLabel() as NSString
-        let longestSize = longest.sizeWithAttributes([NSFontAttributeName: _xAxis.labelFont])
-        _xAxis.labelWidth = floor(longestSize.width + _xAxis.xOffset * 3.5)
-        _xAxis.labelHeight = longestSize.height
+
+        let labelSize = longest.sizeWithAttributes([NSFontAttributeName: _xAxis.labelFont])
+
+        let labelWidth = floor(labelSize.width + _xAxis.xOffset * 3.5)
+        let labelHeight = labelSize.height
+
+        let labelRotatedSize = ChartUtils.sizeOfRotatedRectangle(rectangleWidth: labelSize.width, rectangleHeight:  labelHeight, degrees: _xAxis.labelRotationAngle)
+
+        _xAxis.labelWidth = labelWidth
+        _xAxis.labelHeight = labelHeight
+        _xAxis.labelRotatedWidth = round(labelRotatedSize.width + _xAxis.xOffset * 3.5)
+        _xAxis.labelRotatedHeight = round(labelRotatedSize.height)
     }
 
     public override func renderAxisLabels(context context: CGContext)
@@ -43,32 +52,33 @@ public class ChartXAxisRendererHorizontalBarChart: ChartXAxisRendererBarChart
 
         if (_xAxis.labelPosition == .Top)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentRight + xoffset, align: .Left)
+            drawLabels(context: context, pos: viewPortHandler.contentRight + xoffset, anchor: CGPoint(x: 0.0, y: 0.5))
         }
-        else if (_xAxis.labelPosition == .Bottom)
+        else if (_xAxis.labelPosition == .TopInside)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentLeft - xoffset, align: .Right)
+            drawLabels(context: context, pos: viewPortHandler.contentRight - xoffset, anchor: CGPoint(x: 1.0, y: 0.5))
         }
-        else if (_xAxis.labelPosition == .BottomInside)
+        else if (_xAxis.labelPosition == .Bottom)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentLeft + xoffset, align: .Left)
+            drawLabels(context: context, pos: viewPortHandler.contentLeft - xoffset, anchor: CGPoint(x: 1.0, y: 0.5))
         }
-        else if (_xAxis.labelPosition == .TopInside)
+        else if (_xAxis.labelPosition == .BottomInside)
         {
-            drawLabels(context: context, pos: viewPortHandler.contentRight - xoffset, align: .Right)
+            drawLabels(context: context, pos: viewPortHandler.contentLeft + xoffset, anchor: CGPoint(x: 0.0, y: 0.5))
         }
         else
         { // BOTH SIDED
-            drawLabels(context: context, pos: viewPortHandler.contentLeft - xoffset, align: .Right)
-            drawLabels(context: context, pos: viewPortHandler.contentRight + xoffset, align: .Left)
+            drawLabels(context: context, pos: viewPortHandler.contentRight + xoffset, anchor: CGPoint(x: 0.0, y: 0.5))
+            drawLabels(context: context, pos: viewPortHandler.contentLeft - xoffset, anchor: CGPoint(x: 1.0, y: 0.5))
         }
     }
 
     /// draws the x-labels on the specified y-position
-    internal func drawLabels(context context: CGContext, pos: CGFloat, align: NSTextAlignment)
+    internal override func drawLabels(context context: CGContext, pos: CGFloat, anchor: CGPoint)
     {
         let labelFont = _xAxis.labelFont
         let labelTextColor = _xAxis.labelTextColor
+        let labelRotationAngleRadians = _xAxis.labelRotationAngle * ChartUtils.Math.FDEG2RAD
 
         // pre allocate to save performance (dont allocate in loop)
         var position = CGPoint(x: 0.0, y: 0.0)
@@ -98,15 +108,15 @@ public class ChartXAxisRendererHorizontalBarChart: ChartXAxisRendererBarChart
 
             if (viewPortHandler.isInBoundsY(position.y))
             {
-                drawLabel(context: context, label: label!, xIndex: i, x: pos, y: position.y - _xAxis.labelHeight / 2.0, align: align, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor])
+                drawLabel(context: context, label: label!, xIndex: i, x: pos, y: position.y, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor], anchor: anchor, angleRadians: labelRotationAngleRadians)
             }
         }
     }
 
-    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, align: NSTextAlignment, attributes: [String: NSObject])
+    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, attributes: [String: NSObject], anchor: CGPoint, angleRadians: CGFloat)
     {
         let formattedLabel = _xAxis.valueFormatter?.stringForXValue(xIndex, original: label, viewPortHandler: viewPortHandler) ?? label
-        ChartUtils.drawText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), align: align, attributes: attributes)
+        ChartUtils.drawText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), attributes: attributes, anchor: anchor, angleRadians: angleRadians)
     }
 
     private var _gridLineSegmentsBuffer = [CGPoint](count: 2, repeatedValue: CGPoint())

Charts/Classes/Renderers/ChartXAxisRendererRadarChart.swift

@@ -35,6 +35,8 @@ public class ChartXAxisRendererRadarChart: ChartXAxisRenderer
 
         let labelFont = _xAxis.labelFont
         let labelTextColor = _xAxis.labelTextColor
+        let labelRotationAngleRadians = _xAxis.labelRotationAngle * ChartUtils.Math.FDEG2RAD
+        let drawLabelAnchor = CGPoint(x: 0.5, y: 0.0)
 
         let sliceangle = _chart.sliceAngle
 
@@ -55,16 +57,16 @@ public class ChartXAxisRendererRadarChart: ChartXAxisRenderer
 
             let angle = (sliceangle * CGFloat(i) + _chart.rotationAngle) % 360.0
 
-            let p = ChartUtils.getPosition(center: center, dist: CGFloat(_chart.yRange) * factor + _xAxis.labelWidth / 2.0, angle: angle)
+            let p = ChartUtils.getPosition(center: center, dist: CGFloat(_chart.yRange) * factor + _xAxis.labelRotatedWidth / 2.0, angle: angle)
 
-            drawLabel(context: context, label: label!, xIndex: i, x: p.x, y: p.y - _xAxis.labelHeight / 2.0, align: .Center, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor])
+            drawLabel(context: context, label: label!, xIndex: i, x: p.x, y: p.y - _xAxis.labelRotatedHeight / 2.0, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor], anchor: drawLabelAnchor, angleRadians: labelRotationAngleRadians)
         }
     }
 
-    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, align: NSTextAlignment, attributes: [String: NSObject])
+    internal func drawLabel(context context: CGContext, label: String, xIndex: Int, x: CGFloat, y: CGFloat, attributes: [String: NSObject], anchor: CGPoint, angleRadians: CGFloat)
     {
         let formattedLabel = _xAxis.valueFormatter?.stringForXValue(xIndex, original: label, viewPortHandler: viewPortHandler) ?? label
-        ChartUtils.drawText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), align: align, attributes: attributes)
+        ChartUtils.drawText(context: context, text: formattedLabel, point: CGPoint(x: x, y: y), attributes: attributes, anchor: anchor, angleRadians: angleRadians)
     }
 
     public override func renderLimitLines(context context: CGContext)