core: add support for area charts

FranzCocoa/Backend.swift

@@ -94,6 +94,7 @@ public enum ChartScaleType: Readable, Writable {
 }
 
 public enum ChartStyle: Readable, Writable {
+  case area
   case bar
   case candlestick(UVarint?)
   case line
@@ -103,14 +104,16 @@ public enum ChartStyle: Readable, Writable {
     let tag = UVarint.read(from: inp, using: &buf)
     switch tag {
     case 0x0000:
-      return .bar
+      return .area
     case 0x0001:
+      return .bar
+    case 0x0002:
       return .candlestick(
         UVarint?.read(from: inp, using: &buf)
       )
-    case 0x0002:
-      return .line
     case 0x0003:
+      return .line
+    case 0x0004:
       return .scatter
     default:
       preconditionFailure("ChartStyle: unexpected tag \(tag)")
@@ -119,15 +122,17 @@ public enum ChartStyle: Readable, Writable {
 
   public func write(to out: OutputPort) {
     switch self {
-    case .bar:
+    case .area:
       UVarint(0x0000).write(to: out)
-    case .candlestick(let width):
+    case .bar:
       UVarint(0x0001).write(to: out)
+    case .candlestick(let width):
+      UVarint(0x0002).write(to: out)
       width.write(to: out)
     case .line:
-      UVarint(0x0002).write(to: out)
-    case .scatter:
       UVarint(0x0003).write(to: out)
+    case .scatter:
+      UVarint(0x0004).write(to: out)
     }
   }
 }

FranzCocoa/ResultDetail.swift

@@ -68,18 +68,32 @@ fileprivate struct ChartResult: View {
   private func chartView() -> any View {
     let view = Charts.Chart(pairs) { p in
       switch chart.style {
+      case .area:
+        try? p.areaMark(
+          xLabel: chart.xLabel,
+          yLabel: chart.yLabel
+        )
       case .bar:
-        try? p.barMark(xLabel: chart.xLabel, yLabel: chart.yLabel)
+        try? p.barMark(
+          xLabel: chart.xLabel,
+          yLabel: chart.yLabel
+        )
       case .candlestick(let width):
         try? p.candlestickMark(
           xLabel: chart.xLabel,
           yLabel: chart.yLabel,
           width: width
         )
       case .line:
-        try? p.lineMark(xLabel: chart.xLabel, yLabel: chart.yLabel)
+        try? p.lineMark(
+          xLabel: chart.xLabel,
+          yLabel: chart.yLabel
+        )
       case .scatter:
-        try? p.pointMark(xLabel: chart.xLabel, yLabel: chart.yLabel)
+        try? p.pointMark(
+          xLabel: chart.xLabel,
+          yLabel: chart.yLabel
+        )
       }
     }
     switch (chart.xScale, chart.yScale) {
@@ -98,15 +112,17 @@ fileprivate struct ChartResult: View {
 
   @MainActor
   private func export(frame: CGRect) {
-    guard let image = ImageRenderer(content: AnyView(
+    guard let data = ImageRenderer(content: AnyView(
       chartView()
         .padding(.all, 20)
         .background()
     ).frame(
       width: frame.width * 2,
       height: frame.height * 2
-    )).nsImage else { return }
-    guard let data = image.tiffRepresentation else { return }
+    )).nsImage?.tiffRepresentation else {
+      return
+    }
+
     let dialog = NSSavePanel()
     dialog.allowedContentTypes = [.init(filenameExtension: "tiff")!]
     dialog.isExtensionHidden = false
@@ -142,6 +158,20 @@ fileprivate struct ChartResult: View {
     let x: ChartValue
     let y: ChartValue
 
+    func areaMark(xLabel: String, yLabel: String) throws -> AreaMark {
+      switch (x, y) {
+      case (.categorical(let xcat), .numerical(let y)):
+        return AreaMark(x: .value(xLabel, xcat), y: .value(yLabel, y))
+      case (.timestamp(let ts), .numerical(let y)):
+        return AreaMark(
+          x: .value(xLabel, Date(timeIntervalSince1970: Double(ts))),
+          y: .value(yLabel, y)
+        )
+      default:
+        throw ChartError.badMarks
+      }
+    }
+
     func barMark(xLabel: String, yLabel: String) throws -> BarMark {
       switch (x, y) {
       case (.categorical(let xcat), .categorical(let ycat)):
@@ -152,6 +182,11 @@ fileprivate struct ChartResult: View {
         return BarMark(x: .value(xLabel, x), y: .value(yLabel, ycat))
       case (.numerical(let x), .numerical(let y)):
         return BarMark(x: .value(xLabel, x), y: .value(yLabel, y))
+      case (.timestamp(let ts), .numerical(let y)):
+        return BarMark(
+          x: .value(xLabel, Date(timeIntervalSince1970: Double(ts))),
+          y: .value(yLabel, y)
+        )
       default:
         throw ChartError.badMarks
       }
@@ -188,6 +223,11 @@ fileprivate struct ChartResult: View {
         return LineMark(x: .value(xLabel, x), y: .value(yLabel, ycat))
       case (.numerical(let x), .numerical(let y)):
         return LineMark(x: .value(xLabel, x), y: .value(yLabel, y))
+      case (.timestamp(let ts), .numerical(let y)):
+        return LineMark(
+          x: .value(xLabel, Date(timeIntervalSince1970: Double(ts))),
+          y: .value(yLabel, y)
+        )
       default:
         throw ChartError.badMarks
       }
@@ -203,6 +243,11 @@ fileprivate struct ChartResult: View {
         return PointMark(x: .value(xLabel, x), y: .value(yLabel, ycat))
       case (.numerical(let x), .numerical(let y)):
         return PointMark(x: .value(xLabel, x), y: .value(yLabel, y))
+      case (.timestamp(let ts), .numerical(let y)):
+        return PointMark(
+          x: .value(xLabel, Date(timeIntervalSince1970: Double(ts))),
+          y: .value(yLabel, y)
+        )
       default:
         throw ChartError.badMarks
       }

FranzCross/result-detail.rkt

@@ -80,6 +80,7 @@
                  #:y-label (Chart-y-label c)
                  (list
                   ((match (Chart-style c)
+                     [(ChartStyle.area) area]
                      [(ChartStyle.bar) discrete-histogram]
                      [(ChartStyle.candlestick _) candlesticks]
                      [(ChartStyle.line) lines]
@@ -91,6 +92,14 @@
                       (ChartValue-> (ChartPair-x p))
                       (ChartValue-> (ChartPair-y p))))))))))))
 
+(define (area ps)
+  (define min-y
+    (apply min (map cadr ps)))
+  (lines-interval
+   (for/list ([p (in-list ps)])
+     (list (car p) min-y))
+   ps))
+
 (define (text-view s)
   (hpanel
    #:margin '(20 20)

core/extlib/render.lua

@@ -86,6 +86,7 @@ local function makeChartClass(name)
     return Chart
 end
 
+render.AreaChart = makeChartClass("AreaChart")
 render.BarChart = makeChartClass("BarChart")
 render.CandlestickChart = makeChartClass("CandlestickChart")
 render.LineChart = makeChartClass("LineChart")

core/script.rkt

@@ -46,6 +46,7 @@
    {type : ChartScaleType}])
 
 (define-enum ChartStyle
+  [area]
   [bar]
   [candlestick
    {width : (Optional UVarint)}]
@@ -107,6 +108,8 @@
 
 (define (->ChartStyle type v)
   (case type
+    [(#"AreaChart")
+     (ChartStyle.area)]
     [(#"BarChart")
      (ChartStyle.bar)]
     [(#"CandlestickChart")
@@ -158,7 +161,7 @@
      (define type
        (table-ref v #"__type"))
      (case type
-       [(#"BarChart" #"CandlestickChart" #"LineChart" #"ScatterChart")
+       [(#"AreaChart" #"BarChart" #"CandlestickChart" #"LineChart" #"ScatterChart")
         (ReduceResult.chart
          (make-Chart
           #:style (->ChartStyle type v)

manual/index.scrbl

@@ -816,10 +816,17 @@ data to a window when @tech[#:key "apply"]{applying} a script.
 @(define (chart-ref . content)
   (apply elemref '("lua" "Chart:push") content))
 
+@deflua[render.AreaChart (xlabel ylabel) Chart]{
+  Returns an instance of an area @chart-ref{chart renderer}. The first
+  argument represents the x axis label and the second argument, the y
+  axis label. The values of the x axis must be @lua[render.Timestamp]s
+  or @tt{string}s and the y axis values must be @tt{number}s.
+}
+
 @deflua[render.BarChart (xlabel ylabel) Chart]{
   Returns an instance of a bar @chart-ref{chart renderer}. The first
-  argument represents the x-axis label and the second argument, the
-  y-axis.
+  argument represents the x axis label and the second argument, the
+  y axis.
 }
 
 @deflua[render.CandlestickChart (xlabel ylabel) Chart]{
@@ -854,14 +861,14 @@ data to a window when @tech[#:key "apply"]{applying} a script.
 
 @deflua[render.LineChart (xlabel ylabel) Chart]{
   Returns an instance of a line @chart-ref{chart renderer}. The first
-  argument represents the x-axis label and the second argument, the
-  y-axis.
+  argument represents the x axis label and the second argument, the
+  y axis.
 }
 
 @deflua[render.ScatterChart (xlabel ylabel) Chart]{
   Returns an instance of a scatter @chart-ref{chart renderer}. The first
-  argument represents the x-axis label and the second argument, the
-  y-axis.
+  argument represents the x axis label and the second argument, the
+  y axis.
 }
 
 @deflua[render.Table (columns ...) Table]{