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change x axis to string value(to avoid gaps)
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@kosyloa
kosyloa committed May 21, 2024
1 parent 858641d commit a6a5738
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Showing 2 changed files with 121 additions and 82 deletions.
201 changes: 120 additions & 81 deletions Samples/DXFeedCandleChartMac/CandleStickChart.swift
View file
Original file line number Diff line number Diff line change
Expand Up @@ -92,7 +92,7 @@ enum CandleType: CaseIterable, Identifiable {
func calcualteStartDate() -> Date {
switch self {
case .minute:
return Calendar.current.date(byAdding: .day, value: -1, to: Date())!
return Calendar.current.date(byAdding: .day, value: -7, to: Date())!
case .hour:
return Calendar.current.date(byAdding: .day, value: -7, to: Date())!
case .day:
Expand Down Expand Up @@ -135,12 +135,14 @@ struct StockPrice: Identifiable {
let close: Decimal
let high: Decimal
let low: Decimal
let isPoint: Bool

init(currency: String, timestamp: Date, open: Decimal, close: Decimal, high: Decimal, low: Decimal) {
self.currency = currency
self.timestamp = timestamp
self.open = open
self.close = close
self.isPoint = open == close && high == low
self.high = high
self.low = low
}
Expand All @@ -153,7 +155,6 @@ struct StockPrice: Identifiable {
high: Decimal(candle.high),
low: Decimal(candle.low))
}

}

class CandleList: ObservableObject, SnapshotDelegate {
Expand All @@ -173,8 +174,8 @@ class CandleList: ObservableObject, SnapshotDelegate {

var minDate: Int64 = Int64.max
var maxDate: Int64 = 0

let temp = result.map { candle in
let firstNElements = result.prefix(150)
let temp = firstNElements.map { candle in
let time = candle.time
minDate = min(minDate, time)
maxDate = max(maxDate, time)
Expand All @@ -188,13 +189,17 @@ class CandleList: ObservableObject, SnapshotDelegate {
self.minValue = minValue
self.maxDate = Date(millisecondsSince1970: maxDate + self.type.calculateRightShift())
self.minDate = Date(millisecondsSince1970: minDate - self.type.calculateRightShift())
self.xScrollPosition = temp.first!.timestamp
if temp.count > 30 {
self.xScrollPosition = "\(temp[29].timestamp.timeIntervalSince1970)"
} else {
self.xScrollPosition = "\(temp.last!.timestamp.timeIntervalSince1970)"
}
self.xAxisLabels = self.calculateXaxisValues(with: self.type, values: temp)

self.candles = temp
self.objectWillChange.send()

// print("use \(self.xScrollPosition) \(temp[30])")
// print("Loaded \(self.type) \(temp.count) \(self.minDate) \(self.maxDate) \(self.minValue) \(self.maxValue)")
self.xValues = temp.map({ stock in
"\(stock.timestamp.timeIntervalSince1970)"
}).reversed()
} else {
result.forEach { candle in
self.maxValue = max(self.maxValue, candle.max())
Expand All @@ -209,6 +214,43 @@ class CandleList: ObservableObject, SnapshotDelegate {
}
}
}
private func visiblePointsOnScreen(type: CandleType, valuesCount: Int) -> Int {
switch type {
case .month:
return min(valuesCount, 30)
case .week:
return min(valuesCount, 30)
case .year:
return min(valuesCount, 30)
case .minute:
return min(valuesCount, 30)
case .day:
return min(valuesCount, 30)
case .hour:
return min(valuesCount, 30)
}
}
func calculateXaxisValues(with type: CandleType, values: [StockPrice]) -> [String] {
var visiblePages: Double = 1
let valuesCount = values.count
if #available(iOS 17.0, *) {
let pointsOnScreen = visiblePointsOnScreen(type: type, valuesCount: valuesCount)
visiblePages = Double(valuesCount)/Double(pointsOnScreen)
}
var stringValues = [String]()

// initial case, to avoid showing lines on empty screen
if values.count == 0 {
return [String]()
}

let maxInterval = Int(visiblePages.isNaN ? 1 : visiblePages) * 4
for position in stride(from: 0, to: valuesCount, by: valuesCount / maxInterval) {
stringValues.append("\(values[position].timestamp.timeIntervalSince1970)")
}
return stringValues
}


let symbol: String
public private(set) var currency = ""
Expand All @@ -220,7 +262,9 @@ class CandleList: ObservableObject, SnapshotDelegate {
var snapshotProcessor: SnapshotProcessor!

@Published var candles: [StockPrice]
@Published var xScrollPosition: Date = Date(millisecondsSince1970: 0)
@Published var xScrollPosition: String = ""
@Published var xAxisLabels = [String]()
var xValues = [String]()

var maxValue: Double = 0
var minValue: Double = Double.greatestFiniteMagnitude
Expand Down Expand Up @@ -285,7 +329,7 @@ class CandleList: ObservableObject, SnapshotDelegate {

func fakeLoading() {
loadingInProgress = true
self.xScrollPosition = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
self.xScrollPosition = "\(Calendar.current.date(byAdding: .day, value: -1, to: Date())!.timeIntervalSince1970)"
loadingInProgress = false
}
}
Expand All @@ -301,8 +345,9 @@ struct CandleStickChart: View {

let symbol: String
let xAxisCountPerScreen = 4
var xAxisValues: [String]?

init(symbol: String,
init(symbol: String,
type: CandleType = .week,
endpoint: DXEndpoint?,
ipfAddress: String) {
Expand Down Expand Up @@ -376,11 +421,12 @@ struct CandleStickChart: View {
let price = binding.wrappedValue

CandleStickMark(
timestamp: .value("Date", price.timestamp),
timestamp: .value("Date", "\(price.timestamp.timeIntervalSince1970)"),
open: .value("Open", price.open),
high: .value("High", price.high),
low: .value("Low", price.low),
close: .value("Close", price.close)
close: .value("Close", price.close),
stockPrice: price
)
.accessibilityLabel("""
\(price.timestamp.formatted(date: .numeric, time: .omitted)): \(price.accessibilityTrendSummary)
Expand All @@ -389,28 +435,36 @@ struct CandleStickChart: View {
.accessibilityHidden(false)
.foregroundStyle( price.isClosingHigher ? .green : .red)
}
.chartXScale(domain: [list.minDate, list.maxDate])
.chartXScale(domain: .automatic(dataType: String.self) { dates in
dates = list.xValues
})
.chartYScale(domain: getYScale())
.chartYAxis { AxisMarks(preset: .extended) }
.chartXAxis {

if list.loadingInProgress {

} else {
let numberOfItems = list.candles.count
let xAxisValues = calculateXaxisValues(firstValue: list.minDate, with: type, valuesCount: numberOfItems)
let xAxisValues = self.list.xAxisLabels
AxisMarks(values: xAxisValues) { value in

if let date = value.as(Date.self) {
AxisValueLabel(horizontalSpacing: -14, verticalSpacing: 10) {
switch type {
case .year:
Text(shortDateFormatter.string(from: date))
case .minute:
Text(hourDateFormatter.string(from: date))
default:
Text(dateFormatter.string(from: date))
if let strDate = value.as(String.self) {
if (strDate == xAxisValues.first!) {
// workaround, to avoid ... inctead of latest value(now)
AxisValueLabel("")
} else {
let date = Date(timeIntervalSince1970: TimeInterval(strDate) ?? 0)
AxisValueLabel(horizontalSpacing: -14, verticalSpacing: 10) {
switch type {
case .year:
Text(shortDateFormatter.string(from: date))
case .minute:
Text(hourDateFormatter.string(from: date))
default:
Text(dateFormatter.string(from: date))
}
}
}

}
AxisGridLine(centered: true, stroke: StrokeStyle(lineWidth: 0.5))
AxisTick(centered: true, length: 0, stroke: .none)
Expand Down Expand Up @@ -447,7 +501,7 @@ struct CandleStickChart: View {
GeometryReader { geo in
if let selectedPrice {
let dateInterval = Calendar.current.dateInterval(of: .minute, for: selectedPrice.timestamp)!
let startPositionX1 = proxy.position(forX: dateInterval.start) ?? 0
let startPositionX1 = proxy.position(forX: "\(dateInterval.start.timeIntervalSince1970)") ?? 0

let lineX = startPositionX1 + geo[proxy.plotAreaFrame].origin.x
let lineHeight = geo[proxy.plotAreaFrame].maxY
Expand Down Expand Up @@ -494,28 +548,6 @@ struct CandleStickChart: View {
}
}

func calculateXaxisValues(firstValue: Date, with type: CandleType, valuesCount: Int) -> [Date] {
var visiblePages: Double = 1
if #available(iOS 17.0, *) {
let pointsOnScreen = visiblePointsOnScreen(type: type, valuesCount: valuesCount)
visiblePages = Double(valuesCount)/Double(pointsOnScreen)
}
var values = [Date]()
let endDate = list.maxDate
let delta = endDate.distance(to: firstValue)

// initial case, to avoid showing lines on empty screen
if firstValue == endDate {
return [Date]()
}
let maxInterval = Int(visiblePages.isNaN ? 1 : visiblePages) * xAxisCountPerScreen
for index in 0...maxInterval {
let value = endDate.addingTimeInterval(TimeInterval(index) * delta / TimeInterval(maxInterval))
values.append(value)
}
return values
}

private func visiblePointsOnScreen(type: CandleType, valuesCount: Int) -> Int {
switch type {
case .month:
Expand All @@ -538,32 +570,17 @@ struct CandleStickChart: View {
return 1
}
let pointsOnScreen = visiblePointsOnScreen(type: type, valuesCount: valuesCount)
let hourDuration = 3600
let dayDuration = hourDuration * 24
switch type {
case .month:
return dayDuration * 30 * pointsOnScreen
case .week:
return dayDuration * 7 * pointsOnScreen
case .year:
return dayDuration * 365 * pointsOnScreen
case .minute:
return dayDuration / 48
case .day:
return dayDuration * 1 * pointsOnScreen
case .hour:
return hourDuration * 1 * pointsOnScreen
}
return pointsOnScreen
}

private func findElement(location: CGPoint, proxy: ChartProxy, geometry: GeometryProxy) -> StockPrice? {
let relativeXPosition = location.x - geometry[proxy.plotAreaFrame].origin.x
if let date = proxy.value(atX: relativeXPosition) as Date? {
if let date = proxy.value(atX: relativeXPosition) as String? {
// Find the closest date element.
var minDistance: TimeInterval = .infinity
var index: Int?
for dataIndex in list.candles.indices {
let nthSalesDataDistance = list.candles[dataIndex].timestamp.distance(to: date)
let nthSalesDataDistance = list.candles[dataIndex].timestamp.distance(to: Date(timeIntervalSince1970: TimeInterval(date) ?? 0))
if abs(nthSalesDataDistance) < minDistance {
minDistance = abs(nthSalesDataDistance)
index = dataIndex
Expand All @@ -578,29 +595,51 @@ struct CandleStickChart: View {
}

struct CandleStickMark: ChartContent {
let timestamp: PlottableValue<Date>
let timestamp: PlottableValue<String>
let open: PlottableValue<Decimal>
let high: PlottableValue<Decimal>
let low: PlottableValue<Decimal>
let close: PlottableValue<Decimal>
let stockPrice: StockPrice

var body: some ChartContent {
Plot {
// Composite ChartContent MUST be grouped into a plot for accessibility to work
BarMark(
x: timestamp,
yStart: open,
yEnd: close,
width: 4
)
BarMark(
x: timestamp,
yStart: high,
yEnd: low,
width: 1
)
if stockPrice.isPoint {
PointMark(x: timestamp,
y: open).symbolSize(CandleStickMark.openCloseWidth)
} else {
BarMark(
x: timestamp,
yStart: open,
yEnd: close,
width: MarkDimension(floatLiteral: CandleStickMark.openCloseWidth)
)
BarMark(
x: timestamp,
yStart: high,
yEnd: low,
width: MarkDimension(floatLiteral: CandleStickMark.highLowWidth)
)
}
}
}

static let openCloseWidth: CGFloat = {
if #available(iOS 17, *) {
return 6
} else {
return 4
}
}()

static let highLowWidth: CGFloat = {
if #available(iOS 17, *) {
return 2
} else {
return 1
}
}()
}

// MARK: - Accessibility
Expand Down
2 changes: 1 addition & 1 deletion Samples/QuoteTableApp/QuoteTableViewController.swift
View file
Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,7 @@ extension QuoteTableViewController: UITableViewDelegate {
let alert = UIAlertController(title: symbol, message: "", preferredStyle: .actionSheet)
let candlesAction = UIAlertAction(title: "Candle Chart", style: .default) { _ in
let candleChartViewController = MyUIHostingController(rootView: CandleStickChart(symbol: symbol,
type: .week,
type: .day,
endpoint: self.endpoint,
ipfAddress: "https://demo:[email protected]/ipf?SYMBOL="))
candleChartViewController.title = symbol
Expand Down

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