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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()
}
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