tests

bar_chart.go

@@ -35,11 +35,8 @@ type BarChart struct {
 }
 
 // GetDPI returns the dpi for the chart.
-func (bc BarChart) GetDPI(defaults ...float64) float64 {
+func (bc BarChart) GetDPI() float64 {
 	if bc.DPI == 0 {
-		if len(defaults) > 0 {
-			return defaults[0]
-		}
 		return DefaultDPI
 	}
 	return bc.DPI
@@ -64,7 +61,7 @@ func (bc BarChart) GetWidth() int {
 // GetHeight returns the chart height or the default value.
 func (bc BarChart) GetHeight() int {
 	if bc.Height == 0 {
-		return DefaultChartWidth
+		return DefaultChartHeight
 	}
 	return bc.Height
 }
@@ -72,7 +69,7 @@ func (bc BarChart) GetHeight() int {
 // GetBarSpacing returns the spacing between bars.
 func (bc BarChart) GetBarSpacing() int {
 	if bc.BarSpacing == 0 {
-		return 100
+		return DefaultBarSpacing
 	}
 	return bc.BarSpacing
 }
@@ -80,7 +77,7 @@ func (bc BarChart) GetBarSpacing() int {
 // GetBarWidth returns the default bar width.
 func (bc BarChart) GetBarWidth() int {
 	if bc.BarWidth == 0 {
-		return 40
+		return DefaultBarWidth
 	}
 	return bc.BarWidth
 }
@@ -103,7 +100,7 @@ func (bc BarChart) Render(rp RendererProvider, w io.Writer) error {
 		}
 		bc.defaultFont = defaultFont
 	}
-	r.SetDPI(bc.GetDPI(DefaultDPI))
+	r.SetDPI(bc.GetDPI())
 
 	bc.drawBackground(r)
 

bar_chart_test.go

@@ -0,0 +1,144 @@
+package chart
+
+import (
+	"bytes"
+	"math"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestBarChartProps(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+
+	assert.Equal(DefaultDPI, bc.GetDPI())
+	bc.DPI = 100
+	assert.Equal(100, bc.GetDPI())
+
+	assert.Nil(bc.GetFont())
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+	bc.Font = f
+	assert.NotNil(bc.GetFont())
+
+	assert.Equal(DefaultChartWidth, bc.GetWidth())
+	bc.Width = DefaultChartWidth - 1
+	assert.Equal(DefaultChartWidth-1, bc.GetWidth())
+
+	assert.Equal(DefaultChartHeight, bc.GetHeight())
+	bc.Height = DefaultChartHeight - 1
+	assert.Equal(DefaultChartHeight-1, bc.GetHeight())
+
+	assert.Equal(DefaultBarSpacing, bc.GetBarSpacing())
+	bc.BarSpacing = 150
+	assert.Equal(150, bc.GetBarSpacing())
+
+	assert.Equal(DefaultBarWidth, bc.GetBarWidth())
+	bc.BarWidth = 75
+	assert.Equal(75, bc.GetBarWidth())
+}
+
+func TestBarChartRenderNoBars(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	err := bc.Render(PNG, bytes.NewBuffer([]byte{}))
+	assert.NotNil(err)
+}
+
+func TestBarChartGetRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(-math.MaxFloat64, yr.GetMax())
+	assert.Equal(math.MaxFloat64, yr.GetMin())
+}
+
+func TestBarChartGetRangesBarsMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(10, yr.GetMax())
+	assert.Equal(1, yr.GetMin())
+}
+
+func TestBarChartGetRangesMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		YAxis: YAxis{
+			Range: &ContinuousRange{
+				Min: 5.0,
+				Max: 15.0,
+			},
+			Ticks: []Tick{
+				{Value: 7.0, Label: "Foo"},
+				{Value: 11.0, Label: "Foo2"},
+			},
+		},
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(15, yr.GetMax())
+	assert.Equal(5, yr.GetMin())
+}
+
+func TestBarChartGetRangesTicksMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		YAxis: YAxis{
+			Ticks: []Tick{
+				{Value: 7.0, Label: "Foo"},
+				{Value: 11.0, Label: "Foo2"},
+			},
+		},
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(11, yr.GetMax())
+	assert.Equal(7, yr.GetMin())
+}
+
+func TestBarChartHasAxes(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	assert.False(bc.hasAxes())
+	bc.YAxis = YAxis{
+		Style: StyleShow(),
+	}
+
+	assert.True(bc.hasAxes())
+}

defaults.go

@@ -66,6 +66,11 @@ const (
 	DefaultFloatFormat = "%.2f"
 	// DefaultPercentValueFormat is the default percent format.
 	DefaultPercentValueFormat = "%0.2f%%"
+
+	// DefaultBarSpacing is the default pixel spacing between bars.
+	DefaultBarSpacing = 100
+	// DefaultBarWidth is the default pixel width of bars in a bar chart.
+	DefaultBarWidth = 50
 )
 
 var (

examples/bar_chart/main.go

@@ -14,20 +14,20 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 		Height:   512,
 		BarWidth: 60,
 		XAxis: chart.Style{
-			Show: true,
+			Show: false,
 		},
 		YAxis: chart.YAxis{
 			Style: chart.Style{
-				Show: true,
+				Show: false,
 			},
 		},
 		Bars: []chart.Value{
-			{Value: 5, Label: "Blue"},
+			{Value: 5.25, Label: "Blue"},
-			{Value: 5, Label: "Green"},
+			{Value: 4.88, Label: "Green"},
-			{Value: 4, Label: "Gray"},
+			{Value: 4.74, Label: "Gray"},
-			{Value: 3, Label: "Orange"},
+			{Value: 3.22, Label: "Orange"},
 			{Value: 3, Label: "Test"},
-			{Value: 2, Label: "??"},
+			{Value: 2.27, Label: "??"},
 			{Value: 1, Label: "!!"},
 		},
 	}