The Plotter interface lets you attach custom plotters

plotter.go

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+package kmeans
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+type Plotter interface {
+	Plot(clusters Clusters, iteration int)
+}
+
+// SimplePlotter is the default standard plotter for 2-dimensional data sets
+type SimplePlotter struct {
+}
+
+var colors = []drawing.Color{
+	drawing.ColorFromHex("f92672"),
+	drawing.ColorFromHex("89bdff"),
+	drawing.ColorFromHex("66d9ef"),
+	drawing.ColorFromHex("4b7509"),
+	drawing.ColorFromHex("545250"),
+	drawing.ColorFromHex("67210c"),
+	drawing.ColorFromHex("7acd10"),
+	drawing.ColorFromHex("af619f"),
+	drawing.ColorFromHex("fd971f"),
+	drawing.ColorFromHex("dcc060"),
+}
+
+// Plot draw a 2-dimensional data set into a PNG file named {iteration}.png
+func (p SimplePlotter) Plot(clusters Clusters, iteration int) {
+	var series []chart.Series
+
+	// draw data points
+	for i, c := range clusters {
+		/*
+			col := colorful.Lab(c.Center[0]*1.0, -0.9+(c.Center[1]*1.8), -0.9+(c.Center[2]*1.8))
+			// RGB: col := colorful.Color{R: c.Center[0], G: c.Center[1], B: c.Center[2]}
+			colHex := drawing.ColorFromHex(col.Hex()[1:])
+		*/
+
+		series = append(series, chart.ContinuousSeries{
+			Style: chart.Style{
+				Show:        true,
+				StrokeWidth: chart.Disabled,
+				DotColor:    colors[i%len(colors)],
+				DotWidth:    8},
+			XValues: c.pointsInDimension(0),
+			YValues: c.pointsInDimension(1),
+		})
+	}
+
+	// draw cluster center points
+	series = append(series, chart.ContinuousSeries{
+		Style: chart.Style{
+			Show:        true,
+			StrokeWidth: chart.Disabled,
+			DotColor:    drawing.ColorBlack,
+			DotWidth:    16,
+		},
+		XValues: clusters.centersInDimension(0),
+		YValues: clusters.centersInDimension(1),
+	})
+
+	graph := chart.Chart{
+		Height: 1024,
+		Width:  1024,
+		Series: series,
+		XAxis: chart.XAxis{
+			Style: chart.Style{
+				Show: true,
+			},
+		},
+		YAxis: chart.YAxis{
+			Style: chart.Style{
+				Show: true,
+			},
+		},
+	}
+
+	buffer := bytes.NewBuffer([]byte{})
+	err := graph.Render(chart.PNG, buffer)
+	if err != nil {
+		panic(err)
+	}
+	err = ioutil.WriteFile(fmt.Sprintf("%d.png", iteration), buffer.Bytes(), 0644)
+	if err != nil {
+		panic(err)
+	}
+}