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Add stacked bar chart value labels (#60)

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Jamie Isaacs 2019-03-03 03:33:50 -08:00 committed by Jamie Isaacs
parent 3a7bc55431
commit 21b831a1b1
3 changed files with 265 additions and 0 deletions
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221
_examples/stacked_bar_labels/main.go Normal file
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@ -0,0 +1,221 @@
package main
import (
"os"
"github.com/wcharczuk/go-chart"
"github.com/wcharczuk/go-chart/drawing"
)
func main() {
chart.DefaultBackgroundColor = chart.ColorTransparent
chart.DefaultCanvasColor = chart.ColorTransparent
barWidth := 120
var (
colorWhite = drawing.Color{R: 241, G: 241, B: 241, A: 255}
colorMariner = drawing.Color{R: 60, G: 100, B: 148, A: 255}
colorLightSteelBlue = drawing.Color{R: 182, G: 195, B: 220, A: 255}
colorPoloBlue = drawing.Color{R: 126, G: 155, B: 200, A: 255}
colorSteelBlue = drawing.Color{R: 73, G: 120, B: 177, A: 255}
)
stackedBarChart := chart.StackedBarChart{
Title: "Quarterly Sales",
TitleStyle: chart.StyleShow(),
Background: chart.Style{
Padding: chart.Box{
Top: 100,
},
},
Width: 810,
Height: 500,
XAxis: chart.StyleShow(),
YAxis: chart.StyleShow(),
BarSpacing: 50,
Bars: []chart.StackedBar{
{
Name: "Q1",
Width: barWidth,
Values: []chart.Value{
{
Label: "32K",
Value: 32,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorMariner,
FontColor: colorWhite,
},
},
{
Label: "46K",
Value: 46,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorLightSteelBlue,
FontColor: colorWhite,
},
},
{
Label: "48K",
Value: 48,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorPoloBlue,
FontColor: colorWhite,
},
},
{
Label: "42K",
Value: 42,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorSteelBlue,
FontColor: colorWhite,
},
},
},
},
{
Name: "Q2",
Width: barWidth,
Values: []chart.Value{
{
Label: "45K",
Value: 45,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorMariner,
FontColor: colorWhite,
},
},
{
Label: "60K",
Value: 60,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorLightSteelBlue,
FontColor: colorWhite,
},
},
{
Label: "62K",
Value: 62,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorPoloBlue,
FontColor: colorWhite,
},
},
{
Label: "53K",
Value: 53,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorSteelBlue,
FontColor: colorWhite,
},
},
},
},
{
Name: "Q3",
Width: barWidth,
Values: []chart.Value{
{
Label: "54K",
Value: 54,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorMariner,
FontColor: colorWhite,
},
},
{
Label: "58K",
Value: 58,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorLightSteelBlue,
FontColor: colorWhite,
},
},
{
Label: "55K",
Value: 55,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorPoloBlue,
FontColor: colorWhite,
},
},
{
Label: "47K",
Value: 47,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorSteelBlue,
FontColor: colorWhite,
},
},
},
},
{
Name: "Q4",
Width: barWidth,
Values: []chart.Value{
{
Label: "46K",
Value: 46,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorMariner,
FontColor: colorWhite,
},
},
{
Label: "70K",
Value: 70,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorLightSteelBlue,
FontColor: colorWhite,
},
},
{
Label: "74K",
Value: 74,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorPoloBlue,
FontColor: colorWhite,
},
},
{
Label: "60K",
Value: 60,
Style: chart.Style{
StrokeWidth: .01,
FillColor: colorSteelBlue,
FontColor: colorWhite,
},
},
},
},
},
}
pngFile, err := os.Create("output.png")
if err != nil {
panic(err)
}
if err := stackedBarChart.Render(chart.PNG, pngFile); err != nil {
panic(err)
}
if err := pngFile.Close(); err != nil {
panic(err)
}
}

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_examples/stacked_bar_labels/output.png Normal file
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44
stacked_bar_chart.go
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@ -158,6 +158,33 @@ func (sbc StackedBarChart) drawBar(r Renderer, canvasBox Box, xoffset int, bar S
yoffset += barHeight
}
// draw the labels
yoffset = canvasBox.Top
var lx, ly int
for index, bv := range normalizedBarComponents {
barHeight := int(math.Ceil(bv.Value * float64(canvasBox.Height())))
if len(bv.Label) > 0 {
lx = bxl + ((bxr - bxl) / 2)
ly = yoffset + (barHeight / 2)
bv.Style.InheritFrom(sbc.styleDefaultsStackedBarValue(index)).WriteToRenderer(r)
tb := r.MeasureText(bv.Label)
lx = lx - (tb.Width() >> 1)
ly = ly + (tb.Height() >> 1)
if lx < 0 {
lx = 0
}
if ly < 0 {
lx = 0
}
r.Text(bv.Label, lx, ly)
}
yoffset += barHeight
}
return bxr
}
@ -329,6 +356,9 @@ func (sbc StackedBarChart) styleDefaultsStackedBarValue(index int) Style {
StrokeColor: sbc.GetColorPalette().GetSeriesColor(index),
StrokeWidth: 3.0,
FillColor: sbc.GetColorPalette().GetSeriesColor(index),
FontSize: sbc.getScaledFontSize(),
FontColor: sbc.GetColorPalette().TextColor(),
Font: sbc.GetFont(),
}
}
@ -343,6 +373,20 @@ func (sbc StackedBarChart) styleDefaultsTitle() Style {
})
}
func (sbc StackedBarChart) getScaledFontSize() float64 {
effectiveDimension := util.Math.MinInt(sbc.GetWidth(), sbc.GetHeight())
if effectiveDimension >= 2048 {
return 48.0
} else if effectiveDimension >= 1024 {
return 24.0
} else if effectiveDimension > 512 {
return 18.0
} else if effectiveDimension > 256 {
return 12.0
}
return 10.0
}
func (sbc StackedBarChart) getTitleFontSize() float64 {
effectiveDimension := MinInt(sbc.GetWidth(), sbc.GetHeight())
if effectiveDimension >= 2048 {