1 files changed, 63 insertions, 0 deletions
diff --git a/pkg/plot/scatterchart.go b/pkg/plot/scatterchart.go
new file mode 100644
index 0000000..85de1f3
--- /dev/null
+++ b/pkg/plot/scatterchart.go
@@ -0,0 +1,63 @@
+package plot
+
+import (
+	"bytes"
+
+	"github.com/sgreben/jp/pkg/draw"
+)
+
+// ScatterChart is a scatter plot
+type ScatterChart struct{ draw.Canvas }
+
+// NewScatterChart returns a new line chart
+func NewScatterChart(canvas draw.Canvas) *ScatterChart { return &ScatterChart{canvas} }
+
+func (c *ScatterChart) drawAxes(paddingX, paddingY int, minX, maxX, minY, maxY float64) {
+	buffer := c.GetBuffer()
+	// X axis
+	buffer.SetRow(1, paddingX, buffer.Width, draw.HorizontalLine)
+	// Y axis
+	buffer.SetColumn(1, buffer.Height, paddingX, draw.VerticalLine)
+	// Corner
+	buffer.Set(1, paddingX, draw.CornerBottomLeft)
+	// Labels
+	buffer.WriteRight(1, 1, Ff(minY))
+	buffer.WriteLeft(buffer.Height-1, paddingX, Ff(maxY))
+	buffer.WriteRight(0, paddingX, Ff(minX))
+	buffer.WriteLeft(0, buffer.Width, Ff(maxX))
+}
+
+// Draw implements Chart
+func (c *ScatterChart) Draw(data *DataTable) string {
+	var scaleY, scaleX float64
+
+	minX, maxX, minY, maxY := minMax(data)
+	minLabelWidth := len(Ff(minY))
+	maxLabelWidth := len(Ff(maxY))
+
+	paddingX := minLabelWidth + 1
+	paddingY := 2
+	if minLabelWidth < maxLabelWidth {
+		paddingX = maxLabelWidth + 1
+	}
+	chartWidth := c.Size().Width - (paddingX+1)*c.RuneSize().Width
+	chartHeight := c.Size().Height - paddingY*c.RuneSize().Height
+	scaleX = float64(chartWidth) / (maxX - minX)
+	scaleY = float64(chartHeight) / (maxY - minY)
+
+	for _, point := range data.Rows {
+		if len(point) < 2 {
+			continue
+		}
+		x := int((point[0]-minX)*scaleX + float64((paddingX+1)*c.RuneSize().Width))
+		y := int((point[1]-minY)*scaleY + float64(paddingY*c.RuneSize().Height))
+
+		c.Set(y, x)
+
+	}
+	c.drawAxes(paddingX, paddingY, minX, maxX, minY, maxY)
+
+	b := bytes.NewBuffer(nil)
+	c.GetBuffer().Render(b)
+	return b.String()
+}