fix radar chart negative value rendering bug if startAtZeroEnabled is false for issue #166

Charts/Classes/Charts/BarLineChartViewBase.swift

@@ -217,11 +217,11 @@ public class BarLineChartViewBase: ChartViewBase, UIGestureRecognizerDelegate
             renderer?.drawHighlighted(context: context, indices: _indicesToHightlight)
         }
 
-        // Removes clipping rectangle
-        CGContextRestoreGState(context)
-
         renderer!.drawExtras(context: context)
 
+        // Removes clipping rectangle
+        CGContextRestoreGState(context)
+
         _xAxisRenderer.renderAxisLabels(context: context)
         _leftYAxisRenderer.renderAxisLabels(context: context)
         _rightYAxisRenderer.renderAxisLabels(context: context)

Charts/Classes/Renderers/ChartYAxisRenderer.swift

@@ -230,6 +230,11 @@ public class ChartYAxisRenderer: ChartAxisRendererBase
             pt.x = fixedPosition
             pt.y += offset
 
+            if (pt.y > viewPortHandler.contentRect.height)
+            {
+                continue
+            }
+
             ChartUtils.drawText(context: context, text: text, point: pt, align: textAlign, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor])
         }
     }

Charts/Classes/Renderers/ChartYAxisRendererHorizontalBarChart.swift

@@ -150,7 +150,11 @@ public class ChartYAxisRendererHorizontalBarChart: ChartYAxisRenderer
         var labelFont = _yAxis.labelFont
         var labelTextColor = _yAxis.labelTextColor
 
-        for (var i = 0; i < _yAxis.entryCount; i++)
+        var labelWidth = _yAxis.requiredSize().width
+
+        var modulus = Int(ceil((CGFloat(_yAxis.entryCount) * labelWidth) / (viewPortHandler.contentWidth * viewPortHandler.touchMatrix.a)))
+
+        for (var i = 0; i < _yAxis.entryCount; i += modulus)
         {
             var text = _yAxis.getFormattedLabel(i)
 
@@ -159,6 +163,11 @@ public class ChartYAxisRendererHorizontalBarChart: ChartYAxisRenderer
                 return
             }
 
+            if (positions[i].x < viewPortHandler.contentRect.origin.x)
+            {
+                continue
+            }
+
             ChartUtils.drawText(context: context, text: text, point: CGPoint(x: positions[i].x, y: fixedPosition - offset), align: .Center, attributes: [NSFontAttributeName: labelFont, NSForegroundColorAttributeName: labelTextColor])
         }
     }

Charts/Classes/Renderers/ChartYAxisRendererRadarChart.swift

@@ -69,7 +69,19 @@ public class ChartYAxisRendererRadarChart: ChartYAxisRenderer
         }
         else
         {
-            var first = ceil(Double(yMin) / interval) * interval
+            var rawValue = Double(yMin) / interval
+
+            var first: Double;
+
+            // if raw value negative, we need to use floor rather than ceil
+            if (rawValue < 0)
+            {
+                first = floor(rawValue) * interval
+            }
+            else
+            {
+                first = ceil(Double(yMin) / interval) * interval
+            }
 
             if (first == 0.0)
             { // Fix for IEEE negative zero case (Where value == -0.0, and 0.0 == -0.0)
@@ -104,6 +116,8 @@ public class ChartYAxisRendererRadarChart: ChartYAxisRenderer
         }
 
         _yAxis.axisMaximum = _yAxis.entries[_yAxis.entryCount - 1]
+        // set axisMinimum to be the minimum value.
+        _yAxis.axisMinimum = _yAxis.entries[0]
         _yAxis.axisRange = abs(_yAxis.axisMaximum - _yAxis.axisMinimum)
     }
 
@@ -199,4 +213,4 @@ public class ChartYAxisRendererRadarChart: ChartYAxisRenderer
 
         CGContextRestoreGState(context)
     }
-}
+}