Question 232971 in IOS Swift Question posted in
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Ios swift – How to fill between two lines in a graphic in xcode(swift)?

I have three arrays. xValues, yMinValues and yMaxValues. I want to show a graphic and this graphic must draw two lines by my yminValues and yMaxValues array.Then fill with a color between this lines. I draw all lines but I get a graphic like in that photo and I show

My Code is :
enter image description here

class CustomView: UIView {
    let xValues: [CGFloat] = [0, 2, 4, 6, 8, 10, 12, 14]
    let yMaxValues: [CGFloat] = [4, 6, 9, 10, 10, 11, 10, 11]
    let yMinValues: [CGFloat] = [2, 4, 5, 6, 7, 8, 9, 11]
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        
        guard let context = UIGraphicsGetCurrentContext() else { return }
        
        // Arka planı beyaz yapın
        UIColor.white.setFill()
        context.fill(rect)
        
        // Grafik boyutlarını alın
        let graphWidth = rect.width
        let graphHeight = rect.height
        
        // Min ve max değerleri belirleyin
        let minValue = min(yMinValues.min() ?? 0.0, yMinValues.max() ?? 0.0)
        let maxValue = max(yMaxValues.min() ?? 0.0, yMaxValues.max() ?? 0.0)
        
        // Y değerlerini ölçeklendirin
        let yScaleFactor = graphHeight / (maxValue - minValue)
        
        // X değerlerini ölçeklendirin
        let xScaleFactor = graphWidth / CGFloat(xValues.count - 1)
        
        // Grafik alanını doldurun
        let yFillValuesPath = UIBezierPath()

        // YFillValues için line çizin
        for i in 0..<xValues.count {
            let x = CGFloat(i) * xScaleFactor
            let yFill = graphHeight - (yMinValues[i] - minValue) * yScaleFactor // Burada yMinValues kullanılmalı
            if i == 0 {
                yFillValuesPath.move(to: CGPoint(x: x, y: yFill))
            } else {
                yFillValuesPath.addLine(to: CGPoint(x: x, y: yFill))
            }

            // Noktalara yFillValues değerlerini yaz
            let pointLabel = UILabel(frame: CGRect(x: x - 15, y: yFill - 30, width: 30, height: 30))
            pointLabel.text = "(yMinValues[i])"
            pointLabel.textColor = UIColor.black
            pointLabel.textAlignment = .center
            pointLabel.font = UIFont.systemFont(ofSize: 10)
            addSubview(pointLabel)
        }
        
        // Grafik alanını doldurun
        let fillColor = UIColor(red: 0.5, green: 0.5, blue: 1.0, alpha: 0.5)
        fillColor.setFill()
        
        yFillValuesPath.addLine(to: CGPoint(x: yMaxValues.last ?? 0, y: graphHeight - (yMaxValues.last ?? 0 - minValue) * yScaleFactor)) // yMinValues kullanılmalı
        yFillValuesPath.addLine(to: CGPoint(x: yMinValues.first ?? 0, y: graphHeight - (yMinValues.first ?? 0 - maxValue) * yScaleFactor)) // yMinValues kullanılmalı
    
        
        yFillValuesPath.fill()

        yFillValuesPath.close()
        
        // YValues için line çizin
        let yValuesPath = UIBezierPath()
        for i in 0..<xValues.count {
            let x = CGFloat(i) * xScaleFactor
            let y = graphHeight - (yMaxValues[i] - minValue) * yScaleFactor
            if i == 0 {
                yValuesPath.move(to: CGPoint(x: x, y: y))
            } else {
                yValuesPath.addLine(to: CGPoint(x: x, y: y))
            }
            
            // Noktalara yValues değerlerini yaz
            let pointLabel = UILabel(frame: CGRect(x: x - 15, y: y - 30, width: 30, height: 30))
            pointLabel.text = "(yMaxValues[i])"
            pointLabel.textColor = UIColor.black
            pointLabel.textAlignment = .center
            pointLabel.font = UIFont.systemFont(ofSize: 10)
            addSubview(pointLabel)
        }
        
        // Çizgileri çizin
        let lineColor = UIColor.black.cgColor
        context.setStrokeColor(lineColor)
        yValuesPath.stroke()
        yFillValuesPath.stroke()
        
        // X ekseni çizin
        context.move(to: CGPoint(x: 0, y: graphHeight))
        context.addLine(to: CGPoint(x: graphWidth, y: graphHeight))
        context.strokePath()
        
        // Y ekseni çizin
        context.move(to: CGPoint(x: 0, y: graphHeight))
        context.addLine(to: CGPoint(x: 0, y: 0))
        context.strokePath()
        
        // X değerlerini gösterin
        for i in 0..<xValues.count {
            let x = CGFloat(i) * xScaleFactor
            let label = UILabel(frame: CGRect(x: x - 15, y: graphHeight + 5, width: 30, height: 20))
            label.text = "(xValues[i])"
            label.textColor = UIColor.black
            label.textAlignment = .center
            label.font = UIFont.systemFont(ofSize: 12)
            addSubview(label)
        }
        
        // Y değerlerini gösterin
        for i in 0..<yMaxValues.count {
            let y = graphHeight - (yMaxValues[i] - minValue) * yScaleFactor
            let label = UILabel(frame: CGRect(x: -35, y: y - 10, width: 30, height: 20))
            label.text = "(yMaxValues[i])"
            label.textColor = UIColor.black
            label.textAlignment = .right
            label.font = UIFont.systemFont(ofSize: 12)
            addSubview(label)
        }
    }
}

I want to show a graphic filled with a color between yMinValues array and yMaxValues.

enter image description here : I don’t want to fill outer fields and marked these fields with text in this photo.

Tags:

2

Answers


  1. 0

    Just draw small rectangle corresponding to (X[n],Ymin[n])/(X[n],Ymax[n])/(X[n+1],Ymax[n+1])/(X[n+1],Ymin[n+1]). Then you can stroke the X,Ymin and X,Ymax lines

    ...
    //        yFillValuesPath.fill() <<-- Remove the fill
... 
    // Loop on values
    for i in 1..<xValues.count {
        // Compute path points
        let x0 = CGFloat(i-1) * xScaleFactor
        let x1 = CGFloat(i) * xScaleFactor
        let yMax0 = graphHeight - (yMaxValues[i-1] - minValue) * yScaleFactor
        let yMax1 = graphHeight - (yMaxValues[i] - minValue) * yScaleFactor
        let yMin0 = graphHeight - (yMinValues[i-1] - minValue) * yScaleFactor
        let yMin1 = graphHeight - (yMinValues[i] - minValue) * yScaleFactor
        
        // Fill path
        context.beginPath()
        context.move(to: CGPoint(x: x0, y: yMin0))
        context.addLine(to: CGPoint(x: x0, y: yMax0))
        context.addLine(to: CGPoint(x: x1, y: yMax1))
        context.addLine(to: CGPoint(x: x1, y: yMin1))
        context.closePath()
        context.fillPath() // Fill path without stroke
    }
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  2. 0

    To fill the area between the lines, we need to create a single path.

    So, we start with a "max values line" – actually, a set of points:

    enter image description here

    then we have a "min values line" – also, a set of points:

    enter image description here

    to fill the space, we need to turn those into a single path, in this order:

    enter image description here

    then we can fill and stroke it:

    enter image description here

    Here is your CustomView class, with a few modifications…

    class CustomView: UIView {
    let xValues: [CGFloat] = [0, 2, 4, 6, 8, 10, 12, 14]
    let yMaxValues: [CGFloat] = [4, 6, 9, 10, 10, 11, 10, 11]
    let yMinValues: [CGFloat] = [2, 4, 5, 6, 7, 8, 9, 11]
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        
        guard let context = UIGraphicsGetCurrentContext() else { return }
        
        // Arka planı beyaz yapın
        UIColor.white.setFill()
        context.fill(rect)
        
        // Grafik boyutlarını alın
        let graphWidth = rect.width
        let graphHeight = rect.height
        
        // Min ve max değerleri belirleyin
        let minValue = min(yMinValues.min() ?? 0.0, yMinValues.max() ?? 0.0)
        let maxValue = max(yMaxValues.min() ?? 0.0, yMaxValues.max() ?? 0.0)
        
        // Y değerlerini ölçeklendirin
        let yScaleFactor = graphHeight / (maxValue - minValue)
        
        // X değerlerini ölçeklendirin
        let xScaleFactor = graphWidth / CGFloat(xValues.count - 1)
        
        var yMinPoints: [CGPoint] = []
        var yMaxPoints: [CGPoint] = []

        // build CGPoint arrays for min and max values points
        for i in 0..<xValues.count {
            let x = CGFloat(i) * xScaleFactor
            let yMin = graphHeight - (yMinValues[i] - minValue) * yScaleFactor
            let yMax = graphHeight - (yMaxValues[i] - minValue) * yScaleFactor
            yMinPoints.append(.init(x: x, y: yMin))
            yMaxPoints.append(.init(x: x, y: yMax))
        }
        
        // Grafik alanını doldurun
        let yFillValuesPath = UIBezierPath()

        // build path, starting at first max point
        yFillValuesPath.move(to: yMaxPoints[0])
        // add lines to the remaing max points
        for i in 1..<yMaxPoints.count {
            yFillValuesPath.addLine(to: yMaxPoints[i])
        }
        // reverse the max points
        let yMinReversed = Array(yMinPoints.reversed())
        // add lines to the reversed max points
        for i in 0..<yMinReversed.count {
            yFillValuesPath.addLine(to: yMinReversed[i])
        }
        
        // close the path
        yFillValuesPath.close()
        
        // fill the path
        let fillColor = UIColor(red: 0.0, green: 0.5, blue: 1.0, alpha: 0.5)
        fillColor.setFill()
        yFillValuesPath.fill()
        
        // stroke the path
        let lineColor = UIColor.black
        lineColor.setStroke()
        yFillValuesPath.stroke()

        // add the point labels
        for i in 0..<yMaxPoints.count {
            // Noktalara yFillValues değerlerini yaz
            var pointLabel = UILabel(frame: CGRect(x: yMaxPoints[i].x - 15, y: yMaxPoints[i].y - 30, width: 30, height: 30))
            pointLabel.text = "(yMaxValues[i])"
            pointLabel.textColor = UIColor.black
            pointLabel.textAlignment = .center
            pointLabel.font = UIFont.systemFont(ofSize: 10)
            addSubview(pointLabel)

            pointLabel = UILabel(frame: CGRect(x: yMinPoints[i].x - 15, y: yMinPoints[i].y - 30, width: 30, height: 30))
            pointLabel.text = "(yMinValues[i])"
            pointLabel.textColor = UIColor.black
            pointLabel.textAlignment = .center
            pointLabel.font = UIFont.systemFont(ofSize: 10)
            addSubview(pointLabel)
        }

        // X ekseni çizin
        context.move(to: CGPoint(x: 0, y: graphHeight))
        context.addLine(to: CGPoint(x: graphWidth, y: graphHeight))
        context.strokePath()
        
        // Y ekseni çizin
        context.move(to: CGPoint(x: 0, y: graphHeight))
        context.addLine(to: CGPoint(x: 0, y: 0))
        context.strokePath()
        
        // X değerlerini gösterin
        for i in 0..<xValues.count {
            let x = CGFloat(i) * xScaleFactor
            let label = UILabel(frame: CGRect(x: x - 15, y: graphHeight + 5, width: 30, height: 20))
            label.text = "(xValues[i])"
            label.textColor = UIColor.black
            label.textAlignment = .center
            label.font = UIFont.systemFont(ofSize: 12)
            addSubview(label)
        }
        
        // Y değerlerini gösterin
        for i in 0..<yMaxValues.count {
            let y = graphHeight - (yMaxValues[i] - minValue) * yScaleFactor
            let label = UILabel(frame: CGRect(x: -35, y: y - 10, width: 30, height: 20))
            label.text = "(yMaxValues[i])"
            label.textColor = UIColor.black
            label.textAlignment = .right
            label.font = UIFont.systemFont(ofSize: 12)
            addSubview(label)
        }
    }
}

    Result:

    enter image description here

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