Nice Label Algorithm for Charts with minimum ticks

Question

I need to calculate the Ticklabels and the Tickrange for charts manually.

I know the \"standard\" algorithm for nice ticks (see http://books.google.de/books?id=fvA7

Answer 1

Much BETTER and SIMPLER algorythm on swift. Size is fixed, values are not "hardcoded":

class NiceNumbers {
    /// Returns nice range of specified size. Result min <= min argument, result max >= max argument.
    static func getRange(forMin minInt: Int, max maxInt: Int, ofSize size: Int) -> [Int] {
        let niceMinInt = getMinCloseToZero(min: minInt, max: maxInt)
        let step = Double(maxInt - niceMinInt) / Double(size - 1)
        let niceStepInt = Int(get(for: step, min: false))

        var result = [Int]()
        result.append(niceMinInt)
        for i in 1...size - 1 {
            result.append(niceMinInt + i * Int(niceStepInt))
        }
        return result
    }

    /// Returns nice min or zero if it is much smaller than max.
    static func getMinCloseToZero(min: Int, max: Int) -> Int {
        let nice = get(for: Double(min), min: true)
        return nice <= (Double(max) / 10) ? 0 : Int(nice)
    }

    /// Get nice number. If min is true returns smaller number, if false - bigger one.
    static func get(for number: Double, min: Bool) -> Double {
        if number == 0 { return 0 }
        let exponent = floor(log10(number)) - (min ? 0 : 1)
        let fraction = number / pow(10, exponent)
        let niceFraction = min ? floor(fraction) : ceil(fraction)
        return niceFraction * pow(10, exponent)
    }
}

Tested only on positive numbers.