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Prevent crash when handling empty series data
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- Handle gracefully empty series data by preventing
  optionals from being forced-unwrapped.

- Introduce minor cosmetics improvements.
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Guilherme M. Trein committed Jan 4, 2018
1 parent d8badc7 commit 7c371c8
Showing 1 changed file with 26 additions and 35 deletions.
61 changes: 26 additions & 35 deletions Source/Chart.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -328,8 +328,8 @@ open class Chart: UIControl {
let segments = Chart.segmentLine(series.data as ChartLineSegment, zeroLevel: series.colors.zeroLevel)

segments.forEach({ segment in
let scaledXValues = scaleValuesOnXAxis( segment.map({ return $0.x }) )
let scaledYValues = scaleValuesOnYAxis( segment.map({ return $0.y }) )
let scaledXValues = scaleValuesOnXAxis( segment.map { $0.x } )
let scaledYValues = scaleValuesOnYAxis( segment.map { $0.y } )

if series.line {
drawLine(scaledXValues, yValues: scaledYValues, seriesIndex: index)
Expand All @@ -354,7 +354,6 @@ open class Chart: UIControl {
// MARK: - Scaling

fileprivate func getMinMax() -> (min: ChartPoint, max: ChartPoint) {

// Start with user-provided values

var min = (x: minX, y: minY)
Expand All @@ -363,15 +362,13 @@ open class Chart: UIControl {
// Check in datasets

for series in self.series {
let xValues = series.data.map({ (point: ChartPoint) -> Double in
return point.x })
let yValues = series.data.map({ (point: ChartPoint) -> Double in
return point.y })
let xValues = series.data.map { $0.x }
let yValues = series.data.map { $0.y }

let newMinX = xValues.min()!
let newMinY = yValues.min()!
let newMaxX = xValues.max()!
let newMaxY = yValues.max()!
let newMinX = xValues.minOrZero()
let newMinY = yValues.minOrZero()
let newMaxX = xValues.maxOrZero()
let newMaxY = yValues.maxOrZero()

if min.x == nil || newMinX < min.x! { min.x = newMinX }
if min.y == nil || newMinY < min.y! { min.y = newMinY }
Expand All @@ -381,16 +378,16 @@ open class Chart: UIControl {

// Check in labels

if xLabels != nil {
let newMinX = (xLabels!).min()!
let newMaxX = (xLabels!).max()!
if let xLabels = self.xLabels {
let newMinX = xLabels.minOrZero()
let newMaxX = xLabels.maxOrZero()
if min.x == nil || newMinX < min.x! { min.x = newMinX }
if max.x == nil || newMaxX > max.x! { max.x = newMaxX }
}

if yLabels != nil {
let newMinY = (yLabels!).min()!
let newMaxY = (yLabels!).max()!
if let yLabels = self.yLabels {
let newMinY = yLabels.minOrZero()
let newMaxY = yLabels.maxOrZero()
if min.y == nil || newMinY < min.y! { min.y = newMinY }
if max.y == nil || newMaxY > max.y! { max.y = newMaxY }
}
Expand All @@ -401,7 +398,6 @@ open class Chart: UIControl {
if max.y == nil { max.y = 0 }

return (min: (x: min.x!, y: min.y!), max: (x: max.x!, max.y!))

}

fileprivate func scaleValuesOnXAxis(_ values: [Double]) -> [Double] {
Expand All @@ -419,7 +415,6 @@ open class Chart: UIControl {
}

fileprivate func scaleValuesOnYAxis(_ values: [Double]) -> [Double] {

let height = Double(drawingHeight)
var factor: Double
if max.y - min.y == 0 {
Expand All @@ -434,7 +429,6 @@ open class Chart: UIControl {
}

fileprivate func scaleValueOnYAxis(_ value: Double) -> Double {

let height = Double(drawingHeight)
var factor: Double
if max.y - min.y == 0 {
Expand All @@ -453,7 +447,6 @@ open class Chart: UIControl {
} else {
return scaleValueOnYAxis(zeroLevel)
}

}

// MARK: - Drawings
Expand Down Expand Up @@ -514,7 +507,6 @@ open class Chart: UIControl {
}

fileprivate func drawAxes() {

let context = UIGraphicsGetCurrentContext()!
context.setStrokeColor(axesColor.cgColor)
context.setLineWidth(0.5)
Expand Down Expand Up @@ -546,11 +538,9 @@ open class Chart: UIControl {
context.move(to: CGPoint(x: CGFloat(drawingWidth), y: CGFloat(0)))
context.addLine(to: CGPoint(x: CGFloat(drawingWidth), y: drawingHeight + topInset))
context.strokePath()

}

fileprivate func drawLabelsAndGridOnXAxis() {

let context = UIGraphicsGetCurrentContext()!
context.setStrokeColor(gridColor.cgColor)
context.setLineWidth(0.5)
Expand Down Expand Up @@ -617,14 +607,11 @@ open class Chart: UIControl {
label.frame.origin.x += padding
}
}

self.addSubview(label)
}

}

fileprivate func drawLabelsAndGridOnYAxis() {

let context = UIGraphicsGetCurrentContext()!
context.setStrokeColor(gridColor.cgColor)
context.setLineWidth(0.5)
Expand Down Expand Up @@ -676,11 +663,8 @@ open class Chart: UIControl {
label.frame.origin.y -= label.frame.height

self.addSubview(label)

}

UIGraphicsEndImageContext()

}

// MARK: - Touch events
Expand Down Expand Up @@ -710,7 +694,6 @@ open class Chart: UIControl {
layer.addSublayer(shapeLayer)
layerStore.append(shapeLayer)
}

}

func handleTouchEvents(_ touches: Set<UITouch>, event: UIEvent!) {
Expand Down Expand Up @@ -746,10 +729,9 @@ open class Chart: UIControl {
}
indexes.append(index)
}

delegate!.didTouchChart(self, indexes: indexes, x: x, left: left)

}

override open func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
handleTouchEvents(touches, event: event)
}
Expand Down Expand Up @@ -815,7 +797,6 @@ open class Chart: UIControl {
var segment: ChartLineSegment = []

line.enumerated().forEach { (i, point) in

segment.append(point)
if i < line.count - 1 {
let nextPoint = line[i+1]
Expand All @@ -831,7 +812,6 @@ open class Chart: UIControl {
// End of the line
segments.append(segment)
}

}
return segments
}
Expand All @@ -845,3 +825,14 @@ open class Chart: UIControl {
return (x: (p2.x * dy1 - p1.x * dy2) / (dy1 - dy2), y: level)
}
}

extension Sequence where Element == Double {

func minOrZero() -> Double {
return self.min() ?? 0.0
}

func maxOrZero() -> Double {
return self.max() ?? 0.0
}
}

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