How to set the font for DataLabel in ChartSeries?

[water160]

Description

When generate Chart, the default FontSize of ChartSeries is 10, which is a little larger. Is there any way that I can change the Font, like: FontSize, FontColor, etc. ?

Below is an example:

package main

import (
	"fmt"

	"github.com/xuri/excelize/v2"
)

func main() {
	f := excelize.NewFile()
	defer func() {
		if err := f.Close(); err != nil {
			fmt.Println(err)
		}
	}()

	sheetName := "Sheet1"
	index, err := f.NewSheet(sheetName)
	if err != nil {
		fmt.Println(err)
		return
	}
	f.SetActiveSheet(index)

	data := [][]interface{}{
		{"RL6547E", "Octo", "Nove", nil, "WW46", "WW47", "WW48", "WW49", "WW50"},
		{"Input", 1469, 1190, nil, 200, 300, 123, 243, 324},
		{"Output", 1469, 1190, nil, 200, 300, 123, 243, 324},
		{"Final Yield", 0.9767, 0.9799, nil, 0.9765, 0.9774, 0.9814, 0.9635, 0.9903},
		{"Yield Limit", 0.9500, 0.9500, nil, 0.9500, 0.9500, 0.9500, 0.9500, 0.9500},
	}
	for idx, row := range data {
		cell, err := excelize.CoordinatesToCellName(1, idx+1)
		if err != nil {
			fmt.Println(err)
			return
		}
		if err := f.SetSheetRow("Sheet1", cell, &row); err != nil {
			fmt.Println(err)
			return
		}
	}

	colLen := len(data[0])
	rowLen := len(data)
	maxColAscii := CalcAscii(colLen - 1)
	// maxRowAscii := CalcAscii(rowLen)

	enable, disable := true, false
	barChart := excelize.Chart{
		Dimension: excelize.ChartDimension{
			Height: 350,
			Width:  700,
		},
		Type: excelize.Col,
		Series: []excelize.ChartSeries{
			{
				Name:              fmt.Sprintf("%s!$A$2", sheetName),
				Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
				Values:            fmt.Sprintf("%s!$B$2:$%s$2", sheetName, maxColAscii),
				DataLabelPosition: excelize.ChartDataLabelsPositionAbove,
			},
			{
				Name:              fmt.Sprintf("%s!$A$3", sheetName),
				Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
				Values:            fmt.Sprintf("%s!$B$3:$%s$3", sheetName, maxColAscii),
				DataLabelPosition: excelize.ChartDataLabelsPositionAbove,
			},
		},
		Format: excelize.GraphicOptions{
			ScaleX:          1,
			ScaleY:          1,
			OffsetX:         15,
			OffsetY:         10,
			PrintObject:     &enable,
			LockAspectRatio: false,
			Locked:          &disable,
		},
		Title: []excelize.RichTextRun{
			{
				Text: fmt.Sprintf("%s CP Yield Performance", data[0][0]),
			},
		},
		Legend: excelize.ChartLegend{
			Position:      "bottom",
			ShowLegendKey: false,
		},
		PlotArea: excelize.ChartPlotArea{
			ShowCatName:     false,
			ShowLeaderLines: false,
			ShowPercent:     false,
			ShowSerName:     false,
			ShowVal:         true,
		},
		ShowBlanksAs: "gap",
		YAxis: excelize.ChartAxis{
			MajorGridLines: true,
			Secondary:      true,
			Font: excelize.Font{
				Color: "#000000",
				Size:  10,
			},
		},
	}

	lineChart := excelize.Chart{
		Type: excelize.Line,
		Series: []excelize.ChartSeries{
			{
				Name:              fmt.Sprintf("%s!$A$4", sheetName),
				Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
				Values:            fmt.Sprintf("%s!$B$4:$%s$4", sheetName, maxColAscii),
				DataLabelPosition: excelize.ChartDataLabelsPositionCenter,
				Marker: excelize.ChartMarker{
					Symbol: "none", Size: 9,
				},
			},
			{
				Name:              fmt.Sprintf("%s!$A$5", sheetName),
				Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
				Values:            fmt.Sprintf("%s!$B$5:$%s$5", sheetName, maxColAscii),
				DataLabelPosition: excelize.ChartDataLabelsPositionCenter,
				Marker: excelize.ChartMarker{
					Symbol: "none", Size: 9,
				},
			},
		},
		Legend: excelize.ChartLegend{
			Position:      "bottom",
			ShowLegendKey: false,
		},
		Format: excelize.GraphicOptions{
			ScaleX:          1,
			ScaleY:          1,
			OffsetX:         15,
			OffsetY:         10,
			PrintObject:     &enable,
			LockAspectRatio: false,
			Locked:          &disable,
		},
		PlotArea: excelize.ChartPlotArea{
			ShowCatName:     false,
			ShowLeaderLines: false,
			ShowPercent:     false,
			ShowSerName:     false,
			ShowVal:         true,
			NumFmt: excelize.ChartNumFmt{
				CustomNumFmt: "0.00%",
			},
		},
		ShowBlanksAs: "gap",
		YAxis: excelize.ChartAxis{
			MajorGridLines: true,
			Secondary:      true,
			Font: excelize.Font{
				Color: "#000000",
				Size:  10,
			},
		},
	}

	chartStartCell, err := excelize.CoordinatesToCellName(1, rowLen+1)
	if err != nil {
		fmt.Println(err)
		return
	}

	if err := f.AddChart("Sheet1", chartStartCell,
		&barChart, &lineChart,
	); err != nil {
		fmt.Println(err)
		return
	}

	if err := f.SaveAs("TestCharts.xlsx"); err != nil {
		fmt.Println(err)
	}
}

func CalcAscii(num int) string {
	startAscii := 65 // A
	return string(rune(startAscii + num))
}

Steps to reproduce the issue:

1. run the code above
2. observe the chart
3. the font size is a litter larger

Describe the results you received:
I cannot find any option in ChartSeries

type ChartSeries struct {
	Name              string
	Categories        string
	Values            string
	Sizes             string
	Fill              Fill
	Line              ChartLine
	Marker            ChartMarker
	DataLabelPosition ChartDataLabelPositionType
}

Describe the results you expected:
Change the font like XAxis or YAxis

Output of go version:
1.23.1

Excelize version or commit ID:
github.com/xuri/excelize/v2 v2.9.0

Environment details (OS, Microsoft Excel™ version, physical, etc.):
OS: Windows 11
Excel version: Microsoft Office Home and Student 2019

[xuri]

Thanks for your issue. I added a new field DataLabel in the ChartSeries data type to support to sets the format of the chart series data label. For example:

package main

import (
    "fmt"

    "github.com/xuri/excelize/v2"
)

func main() {
    f := excelize.NewFile()
    defer func() {
        if err := f.Close(); err != nil {
            fmt.Println(err)
        }
    }()

    sheetName := "Sheet1"
    index, err := f.NewSheet(sheetName)
    if err != nil {
        fmt.Println(err)
        return
    }
    f.SetActiveSheet(index)

    data := [][]interface{}{
        {"RL6547E", "Octo", "Nove", nil, "WW46", "WW47", "WW48", "WW49", "WW50"},
        {"Input", 1469, 1190, nil, 200, 300, 123, 243, 324},
        {"Output", 1469, 1190, nil, 200, 300, 123, 243, 324},
        {"Final Yield", 0.9767, 0.9799, nil, 0.9765, 0.9774, 0.9814, 0.9635, 0.9903},
        {"Yield Limit", 0.9500, 0.9500, nil, 0.9500, 0.9500, 0.9500, 0.9500, 0.9500},
    }
    for idx, row := range data {
        cell, err := excelize.CoordinatesToCellName(1, idx+1)
        if err != nil {
            fmt.Println(err)
            return
        }
        if err := f.SetSheetRow("Sheet1", cell, &row); err != nil {
            fmt.Println(err)
            return
        }
    }

    colLen := len(data[0])
    rowLen := len(data)
    maxColAscii := CalcAscii(colLen - 1)
    // maxRowAscii := CalcAscii(rowLen)

    enable, disable := true, false
    barChart := excelize.Chart{
        Dimension: excelize.ChartDimension{
            Height: 350,
            Width:  700,
        },
        Type: excelize.Col,
        Series: []excelize.ChartSeries{
            {
                Name:              fmt.Sprintf("%s!$A$2", sheetName),
                Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
                Values:            fmt.Sprintf("%s!$B$2:$%s$2", sheetName, maxColAscii),
                DataLabelPosition: excelize.ChartDataLabelsPositionAbove,
            },
            {
                Name:              fmt.Sprintf("%s!$A$3", sheetName),
                Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
                Values:            fmt.Sprintf("%s!$B$3:$%s$3", sheetName, maxColAscii),
                DataLabelPosition: excelize.ChartDataLabelsPositionAbove,
            },
        },
        Format: excelize.GraphicOptions{
            ScaleX:          1,
            ScaleY:          1,
            OffsetX:         15,
            OffsetY:         10,
            PrintObject:     &enable,
            LockAspectRatio: false,
            Locked:          &disable,
        },
        Title: []excelize.RichTextRun{
            {
                Text: fmt.Sprintf("%s CP Yield Performance", data[0][0]),
            },
        },
        Legend: excelize.ChartLegend{
            Position:      "bottom",
            ShowLegendKey: false,
        },
        PlotArea: excelize.ChartPlotArea{
            ShowCatName:     false,
            ShowLeaderLines: false,
            ShowPercent:     false,
            ShowSerName:     false,
            ShowVal:         true,
        },
        ShowBlanksAs: "gap",
        YAxis: excelize.ChartAxis{
            MajorGridLines: true,
            Secondary:      true,
            Font: excelize.Font{
                Color: "#000000",
                Size:  15,
            },
        },
    }

    lineChart := excelize.Chart{
        Type: excelize.Line,
        Series: []excelize.ChartSeries{
            {
                Name:              fmt.Sprintf("%s!$A$4", sheetName),
                Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
                Values:            fmt.Sprintf("%s!$B$4:$%s$4", sheetName, maxColAscii),
                DataLabelPosition: excelize.ChartDataLabelsPositionCenter,
                Marker: excelize.ChartMarker{
                    Symbol: "none", Size: 9,
                },
+               DataLabel: excelize.ChartDataLabel{
+                   Font: excelize.Font{
+                       Size: 22,
+                   },
+                   Fill: excelize.Fill{Type: "pattern", Color: []string{"C7EECF"}, Pattern: 1},
+               },
            },
            {
                Name:              fmt.Sprintf("%s!$A$5", sheetName),
                Categories:        fmt.Sprintf("%s!$B$1:$%s$1", sheetName, maxColAscii),
                Values:            fmt.Sprintf("%s!$B$5:$%s$5", sheetName, maxColAscii),
                DataLabelPosition: excelize.ChartDataLabelsPositionCenter,
                Marker: excelize.ChartMarker{
                    Symbol: "none", Size: 9,
                },
            },
        },
        Legend: excelize.ChartLegend{
            Position:      "bottom",
            ShowLegendKey: false,
        },
        Format: excelize.GraphicOptions{
            ScaleX:          1,
            ScaleY:          1,
            OffsetX:         15,
            OffsetY:         10,
            PrintObject:     &enable,
            LockAspectRatio: false,
            Locked:          &disable,
        },
        PlotArea: excelize.ChartPlotArea{
            ShowCatName:     false,
            ShowLeaderLines: false,
            ShowPercent:     false,
            ShowSerName:     false,
            ShowVal:         true,
            NumFmt: excelize.ChartNumFmt{
                CustomNumFmt: "0.00%",
            },
        },
        ShowBlanksAs: "gap",
        YAxis: excelize.ChartAxis{
            MajorGridLines: true,
            Secondary:      true,
            Font: excelize.Font{
                Color: "#000000",
                Size:  10,
            },
        },
    }

    chartStartCell, err := excelize.CoordinatesToCellName(1, rowLen+1)
    if err != nil {
        fmt.Println(err)
        return
    }

    if err := f.AddChart("Sheet1", chartStartCell,
        &barChart, &lineChart,
    ); err != nil {
        fmt.Println(err)
        return
    }

    if err := f.SaveAs("TestCharts.xlsx"); err != nil {
        fmt.Println(err)
    }
}

func CalcAscii(num int) string {
    startAscii := 65 // A
    return string(rune(startAscii + num))
}

This feature will be released on the next version.

[water160]

This feature really helps a lot, Thanks!

[xuri]

You're welcome. If you have enjoyed the productivity of using my open-source projects, consider sponsorship though GitHub sponsors, thanks.