FranzCocoa,ResultDetail: enable programmatic control of candle widths

Bogdanp · Nov 5, 2023 · 33d2f9d · 33d2f9d
1 parent 1802f6c
commit 33d2f9d
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Showing 5 changed files with 19 additions and 24 deletions.
diff --git a/FranzCocoa/Backend.swift b/FranzCocoa/Backend.swift
@@ -95,7 +95,7 @@ public enum ChartScaleType: Readable, Writable {
 
 public enum ChartStyle: Readable, Writable {
   case bar
-  case candlestick(UVarint)
+  case candlestick(UVarint?)
   case line
   case scatter
 
@@ -106,7 +106,7 @@ public enum ChartStyle: Readable, Writable {
       return .bar
     case 0x0001:
       return .candlestick(
-        UVarint.read(from: inp, using: &buf)
+        UVarint?.read(from: inp, using: &buf)
       )
     case 0x0002:
       return .line

diff --git a/FranzCocoa/ResultDetail.swift b/FranzCocoa/ResultDetail.swift
@@ -1,4 +1,5 @@
 import Charts
+import NoiseSerde
 import SwiftUI
 
 struct ResultDetail: View {
@@ -61,11 +62,11 @@ fileprivate struct ChartResult: View {
       switch chart.style {
       case .bar:
         try? p.barMark(xLabel: chart.xLabel, yLabel: chart.yLabel)
-      case .candlestick:
+      case .candlestick(let width):
         try? p.candlestickMark(
           xLabel: chart.xLabel,
           yLabel: chart.yLabel,
-          previous: p.id > 0 && p.id < ps.endIndex ? ps[p.id-1] : nil
+          width: width
         )
       case .line:
         try? p.lineMark(xLabel: chart.xLabel, yLabel: chart.yLabel)
@@ -91,21 +92,17 @@ fileprivate struct ChartResult: View {
     case badMarks
   }
 
-  private enum CandlestickDirection {
-    case up
-    case down
-  }
-
   private struct CandlestickMark<X: Plottable, Y: Plottable>: ChartContent {
     let x: PlottableValue<X>
     let o: PlottableValue<Y>
     let h: PlottableValue<Y>
     let l: PlottableValue<Y>
     let c: PlottableValue<Y>
+    let w: UVarint?
 
     var body: some ChartContent {
       RectangleMark(x: x, yStart: l, yEnd: h, width: 1)
-      RectangleMark(x: x, yStart: o, yEnd: c, width: 14)
+      RectangleMark(x: x, yStart: o, yEnd: c, width: MarkDimension(integerLiteral: Int(w ?? 14)))
     }
   }
 
@@ -132,25 +129,19 @@ fileprivate struct ChartResult: View {
     func candlestickMark(
       xLabel: String,
       yLabel: String,
-      previous: Pair?
+      width: UVarint?
     ) throws -> some ChartContent {
       switch (x, y) {
       case (.timestamp(let ts), .candlestick(let o, let h, let l, let c)):
-        var direction: CandlestickDirection
-        switch previous?.y {
-        case .some(.candlestick(_, _, _, let oc)):
-          direction = oc > c ? .down : .up
-        default:
-          direction = .up
-        }
         return CandlestickMark(
           x: .value("Date", Date(timeIntervalSince1970: Double(ts))),
           o: .value("Open", o),
           h: .value("High", h),
           l: .value("Low", l),
-          c: .value("Close", c)
+          c: .value("Close", c),
+          w: width
         )
-        .foregroundStyle(direction == .down ? .red : .green)
+        .foregroundStyle(o > c ? .red : .green)
       default:
         throw ChartError.badMarks
       }

diff --git a/FranzCross/result-detail.rkt b/FranzCross/result-detail.rkt
@@ -57,8 +57,9 @@
                 (ormap ChartValue.timestamp? (Chart-ys c)))
               (parameterize ([candlestick-width
                               (match (Chart-style c)
-                                [(ChartStyle.candlestick width) width]
-                                [_ 1])]
+                                [(ChartStyle.candlestick width)
+                                 (or width 60)]
+                                [_ 60])]
                              [plot-x-ticks
                               (if x-date-ticks?
                                   (date-ticks)

diff --git a/core/script.rkt b/core/script.rkt
@@ -45,7 +45,7 @@
 (define-enum ChartStyle
   [bar]
   [candlestick
-   {width : UVarint}]
+   {width : (Optional UVarint)}]
   [line]
   [scatter])
 
@@ -106,7 +106,7 @@
     [(#"CandlestickChart")
      (ChartStyle.candlestick
       (let ([width (table-ref v #"candlestick_width")])
-        (if (nil? width) 1 (inexact->exact width))))]
+        (if (nil? width) #f (inexact->exact width))))]
     [(#"LineChart")
      (ChartStyle.line)]
     [(#"ScatterChart")

diff --git a/manual/index.scrbl b/manual/index.scrbl
@@ -812,6 +812,9 @@ aggregated data to a window when applying a script.
   chart. The width of a candle must be the length of the interval (in
   seconds) between x ticks on the chart. For example, if the chart is to
   display daily candles, the width of each candle would be @tt{86400}.
+
+  On macOS, this method controls the pixel width of the candles. Use it
+  to make thinner candles when necessary.
 }
 
 @deflua[render.Candlestick (o h l c) Candlestick]{