Initial commit of details_box.go and example

details_box.go

@@ -0,0 +1,74 @@
+package chart
+
+import (
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+// DetailsBox adds a box with additional text
+func DetailsBox(c *Chart, text []string, userDefaults ...Style) Renderable {
+	return func(r Renderer, box Box, chartDefaults Style) {
+		// default style
+		defaults := Style{
+			FillColor:   drawing.ColorWhite,
+			FontColor:   DefaultTextColor,
+			FontSize:    8.0,
+			StrokeColor: DefaultAxisColor,
+			StrokeWidth: DefaultAxisLineWidth,
+		}
+
+		var style Style
+		if len(userDefaults) > 0 {
+			style = userDefaults[0].InheritFrom(chartDefaults.InheritFrom(defaults))
+		} else {
+			style = chartDefaults.InheritFrom(defaults)
+		}
+
+		contentPadding := Box{
+			Top:    box.Height(),
+			Left:   5,
+			Right:  5,
+			Bottom: box.Height(),
+		}
+
+		contentBox := Box{
+			Bottom: box.Height(),
+			Left:   5,
+		}
+
+		content := Box{
+			Top:    contentBox.Bottom - 5,
+			Left:   contentBox.Left + contentPadding.Left,
+			Right:  contentBox.Left + contentPadding.Left,
+			Bottom: contentBox.Bottom - 5,
+		}
+
+		style.GetTextOptions().WriteToRenderer(r)
+
+		// measure and add size of text to box height and width
+		for _, t := range text {
+			textbox := r.MeasureText(t)
+			content.Top -= textbox.Height()
+			right := content.Left + textbox.Width()
+			content.Right = MaxInt(content.Right, right)
+		}
+
+		contentBox = contentBox.Grow(content)
+		contentBox.Right = content.Right + contentPadding.Right
+		contentBox.Top = content.Top - 5
+
+		// draw the box
+		Draw.Box(r, contentBox, style)
+
+		style.GetTextOptions().WriteToRenderer(r)
+
+		// add the text
+		ycursor := content.Top
+		x := content.Left
+		for _, t := range text {
+			textbox := r.MeasureText(t)
+			y := ycursor + textbox.Height()
+			r.Text(t, x, y)
+			ycursor += textbox.Height()
+		}
+	}
+}

examples/details_box/main.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"math/rand"
+	"os"
+	"time"
+
+	chart "github.com/wcharczuk/go-chart"
+)
+
+func random(min, max float64) float64 {
+	return rand.Float64()*(max-min) + min
+}
+
+func main() {
+	/*
+		This is an example of using `DetailsBox` to add a box with additional
+		information about the graph.
+	*/
+	xValues := make([]time.Time, 0)
+	yValues := make([][]float64, 3)
+	for i := 0; i < 50; i++ {
+		xValues = append(xValues, time.Now().Add(time.Duration(i)*time.Minute))
+
+		for j := 0; j < 3; j++ {
+			yValues[j] = append(yValues[j], random(float64(0), float64(20)))
+		}
+	}
+
+	   	seriesOne := chart.TimeSeries{
+	   		Name:    "Series One",
+	   		XValues: xValues,
+	   		YValues: yValues[0],
+	   	}
+
+	   	seriesTwo := chart.TimeSeries{
+	   		Name:    "Series Two",
+	   		XValues: xValues,
+	   		YValues: yValues[1],
+		   }
+
+		seriesThree := chart.TimeSeries{
+			Name: "Series Three",
+			XValues: xValues,
+			YValues: yValues[2],
+		}
+
+	graph := chart.Chart{
+		Series: []chart.Series{
+			seriesOne,
+			seriesTwo,
+			seriesThree,
+		},
+		Background: chart.Style{
+			Padding: chart.Box{
+				Left: 120,
+			},
+		},
+	}
+
+	graph.Elements = []chart.Renderable{
+		chart.LegendLeft(&graph),
+		chart.DetailsBox(&graph, []string{
+			"M-F 8:00 am - 6:00 pm",
+			"Poll for data every 9 min.",
+		}),
+	}
+
+	f, _ := os.Create("output.png")
+	defer f.Close()
+	graph.Render(chart.PNG, f)
+}