diff --git a/bar_chart.go b/bar_chart.go
index 0ac9f47..26f8da5 100644
--- a/bar_chart.go
+++ b/bar_chart.go
@@ -32,6 +32,7 @@ type barChart struct {
 	opt *BarChartOption
 }
 
+// NewBarChart returns a bar chart renderer
 func NewBarChart(p *Painter, opt BarChartOption) *barChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
@@ -43,6 +44,7 @@ func NewBarChart(p *Painter, opt BarChartOption) *barChart {
 }
 
 type BarChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
@@ -155,7 +157,7 @@ func (b *barChart) render(result *defaultRenderResult, seriesList SeriesList) (B
 			if distance == 0 {
 				distance = 5
 			}
-			text := NewValueLabelFormater(seriesNames, series.Label.Formatter)(index, item.Value, -1)
+			text := NewValueLabelFormatter(seriesNames, series.Label.Formatter)(index, item.Value, -1)
 			labelStyle := Style{
 				FontColor: theme.GetTextColor(),
 				FontSize:  labelFontSize,
diff --git a/charts.go b/charts.go
index a2e0ec0..6c1c92b 100644
--- a/charts.go
+++ b/charts.go
@@ -35,11 +35,14 @@ const defaultStrokeWidth = 2.0
 var defaultChartWidth = 600
 var defaultChartHeight = 400
 
+// SetDefaultWidth sets default width of chart
 func SetDefaultWidth(width int) {
 	if width > 0 {
 		defaultChartWidth = width
 	}
 }
+
+// SetDefaultHeight sets default height of chart
 func SetDefaultHeight(height int) {
 	if height > 0 {
 		defaultChartHeight = height
diff --git a/funnel_chart.go b/funnel_chart.go
index 7c04bfe..719853a 100644
--- a/funnel_chart.go
+++ b/funnel_chart.go
@@ -34,6 +34,7 @@ type funnelChart struct {
 	opt *FunnelChartOption
 }
 
+// NewFunnelSeriesList returns a series list for funnel
 func NewFunnelSeriesList(values []float64) SeriesList {
 	seriesList := make(SeriesList, len(values))
 	for index, value := range values {
@@ -44,6 +45,7 @@ func NewFunnelSeriesList(values []float64) SeriesList {
 	return seriesList
 }
 
+// NewFunnelChart returns a funnel chart renderer
 func NewFunnelChart(p *Painter, opt FunnelChartOption) *funnelChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
@@ -55,6 +57,7 @@ func NewFunnelChart(p *Painter, opt FunnelChartOption) *funnelChart {
 }
 
 type FunnelChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
diff --git a/grid.go b/grid.go
index 252fe2e..fb5dad6 100644
--- a/grid.go
+++ b/grid.go
@@ -28,16 +28,25 @@ type gridPainter struct {
 }
 
 type GridPainterOption struct {
-	StrokeWidth       float64
-	StrokeColor       Color
-	Column            int
-	Row               int
-	IgnoreFirstRow    bool
-	IgnoreLastRow     bool
+	// The stroke width
+	StrokeWidth float64
+	// The stroke color
+	StrokeColor Color
+	// The column of grid
+	Column int
+	// The row of grid
+	Row int
+	// Ignore first row
+	IgnoreFirstRow bool
+	// Ignore last row
+	IgnoreLastRow bool
+	// Ignore first column
 	IgnoreFirstColumn bool
-	IgnoreLastColumn  bool
+	// Ignore last column
+	IgnoreLastColumn bool
 }
 
+// NewGridPainter returns new a grid renderer
 func NewGridPainter(p *Painter, opt GridPainterOption) *gridPainter {
 	return &gridPainter{
 		p:   p,
diff --git a/horizontal_bar_chart.go b/horizontal_bar_chart.go
index fb23734..30a9b7d 100644
--- a/horizontal_bar_chart.go
+++ b/horizontal_bar_chart.go
@@ -33,6 +33,7 @@ type horizontalBarChart struct {
 }
 
 type HorizontalBarChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
@@ -50,6 +51,7 @@ type HorizontalBarChartOption struct {
 	Legend LegendOption
 }
 
+// NewHorizontalBarChart returns a horizontal bar chart renderer
 func NewHorizontalBarChart(p *Painter, opt HorizontalBarChartOption) *horizontalBarChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
diff --git a/legend.go b/legend.go
index 65db102..2acd35b 100644
--- a/legend.go
+++ b/legend.go
@@ -36,6 +36,7 @@ const IconRect = "rect"
 const IconLineDot = "lineDot"
 
 type LegendOption struct {
+	// The theme
 	Theme ColorPalette
 	// Text array of legend
 	Data []string
@@ -60,6 +61,7 @@ type LegendOption struct {
 	Show *bool
 }
 
+// NewLegendOption returns a legend option
 func NewLegendOption(labels []string, left ...string) LegendOption {
 	opt := LegendOption{
 		Data: labels,
@@ -70,6 +72,7 @@ func NewLegendOption(labels []string, left ...string) LegendOption {
 	return opt
 }
 
+// IsEmpty checks legend is empty
 func (opt *LegendOption) IsEmpty() bool {
 	isEmpty := true
 	for _, v := range opt.Data {
@@ -81,6 +84,7 @@ func (opt *LegendOption) IsEmpty() bool {
 	return isEmpty
 }
 
+// NewLegendPainter returns a legend renderer
 func NewLegendPainter(p *Painter, opt LegendOption) *legendPainter {
 	return &legendPainter{
 		p:   p,
diff --git a/line_chart.go b/line_chart.go
index f171813..0770447 100644
--- a/line_chart.go
+++ b/line_chart.go
@@ -32,6 +32,7 @@ type lineChart struct {
 	opt *LineChartOption
 }
 
+// NewLineChart returns a line chart render
 func NewLineChart(p *Painter, opt LineChartOption) *lineChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
@@ -43,6 +44,7 @@ func NewLineChart(p *Painter, opt LineChartOption) *lineChart {
 }
 
 type LineChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
diff --git a/mark_line.go b/mark_line.go
index a0efcfb..af1062d 100644
--- a/mark_line.go
+++ b/mark_line.go
@@ -27,6 +27,7 @@ import (
 	"github.com/wcharczuk/go-chart/v2"
 )
 
+// NewMarkLine returns a series mark line
 func NewMarkLine(markLineTypes ...string) SeriesMarkLine {
 	data := make([]SeriesMarkData, len(markLineTypes))
 	for index, t := range markLineTypes {
@@ -48,6 +49,7 @@ func (m *markLinePainter) Add(opt markLineRenderOption) {
 	m.options = append(m.options, opt)
 }
 
+// NewMarkLinePainter returns a mark line renderer
 func NewMarkLinePainter(p *Painter) *markLinePainter {
 	return &markLinePainter{
 		p:       p,
diff --git a/mark_point.go b/mark_point.go
index 014b17f..f6c93f3 100644
--- a/mark_point.go
+++ b/mark_point.go
@@ -27,6 +27,7 @@ import (
 	"github.com/wcharczuk/go-chart/v2/drawing"
 )
 
+// NewMarkPoint returns a series mark point
 func NewMarkPoint(markPointTypes ...string) SeriesMarkPoint {
 	data := make([]SeriesMarkData, len(markPointTypes))
 	for index, t := range markPointTypes {
@@ -55,6 +56,7 @@ type markPointRenderOption struct {
 	Points    []Point
 }
 
+// NewMarkPointPainter returns a mark point renderer
 func NewMarkPointPainter(p *Painter) *markPointPainter {
 	return &markPointPainter{
 		p:       p,
diff --git a/painter.go b/painter.go
index da07007..c250369 100644
--- a/painter.go
+++ b/painter.go
@@ -136,7 +136,7 @@ func PainterWidthHeightOption(width, height int) PainterOption {
 	}
 }
 
-// NewPainter creates a new painter
+// NewPainter creates a painter
 func NewPainter(opts PainterOptions, opt ...PainterOption) (*Painter, error) {
 	if opts.Width <= 0 || opts.Height <= 0 {
 		return nil, errors.New("width/height can not be nil")
diff --git a/pie_chart.go b/pie_chart.go
index 972b4c1..6382140 100644
--- a/pie_chart.go
+++ b/pie_chart.go
@@ -36,6 +36,7 @@ type pieChart struct {
 }
 
 type PieChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
@@ -51,6 +52,7 @@ type PieChartOption struct {
 	backgroundIsFilled bool
 }
 
+// NewPieChart returns a pie chart renderer
 func NewPieChart(p *Painter, opt PieChartOption) *pieChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
diff --git a/radar_chart.go b/radar_chart.go
index 5b8aa85..eab70d5 100644
--- a/radar_chart.go
+++ b/radar_chart.go
@@ -45,6 +45,7 @@ type RadarIndicator struct {
 }
 
 type RadarChartOption struct {
+	// The theme
 	Theme ColorPalette
 	// The font size
 	Font *truetype.Font
@@ -62,6 +63,7 @@ type RadarChartOption struct {
 	backgroundIsFilled bool
 }
 
+// NewRadarIndicators returns a radar indicator list
 func NewRadarIndicators(names []string, values []float64) []RadarIndicator {
 	if len(names) != len(values) {
 		return nil
@@ -76,6 +78,7 @@ func NewRadarIndicators(names []string, values []float64) []RadarIndicator {
 	return indicators
 }
 
+// NewRadarChart returns a radar chart renderer
 func NewRadarChart(p *Painter, opt RadarChartOption) *radarChart {
 	if opt.Theme == nil {
 		opt.Theme = defaultTheme
diff --git a/range.go b/range.go
index d5a9ef7..579a77f 100644
--- a/range.go
+++ b/range.go
@@ -37,13 +37,19 @@ type axisRange struct {
 }
 
 type AxisRangeOption struct {
-	Min         float64
-	Max         float64
-	Size        int
-	Boundary    bool
+	// The min value of axis
+	Min float64
+	// The max value of axis
+	Max float64
+	// The size of axis
+	Size int
+	// Boundary gap
+	Boundary bool
+	// The count of divide
 	DivideCount int
 }
 
+// NewRange returns a axis range
 func NewRange(opt AxisRangeOption) axisRange {
 	max := opt.Max
 	min := opt.Min
@@ -88,6 +94,7 @@ func NewRange(opt AxisRangeOption) axisRange {
 	}
 }
 
+// Values returns values of range
 func (r axisRange) Values() []string {
 	offset := (r.max - r.min) / float64(r.divideCount)
 	values := make([]string, 0)
@@ -108,10 +115,13 @@ func (r *axisRange) getRestHeight(value float64) int {
 	return r.size - r.getHeight(value)
 }
 
+// GetRange returns a range of index
 func (r *axisRange) GetRange(index int) (float64, float64) {
 	unit := float64(r.size) / float64(r.divideCount)
 	return unit * float64(index), unit * float64(index+1)
 }
+
+// AutoDivide divides the axis
 func (r *axisRange) AutoDivide() []int {
 	return autoDivide(r.size, r.divideCount)
 }
diff --git a/series.go b/series.go
index 44c4749..87a719f 100644
--- a/series.go
+++ b/series.go
@@ -36,6 +36,7 @@ type SeriesData struct {
 	Style Style
 }
 
+// NewSeriesListDataFromValues returns a series list
 func NewSeriesListDataFromValues(values [][]float64, chartType ...string) SeriesList {
 	seriesList := make(SeriesList, len(values))
 	for index, value := range values {
@@ -44,6 +45,7 @@ func NewSeriesListDataFromValues(values [][]float64, chartType ...string) Series
 	return seriesList
 }
 
+// NewSeriesFromValues returns a series
 func NewSeriesFromValues(values []float64, chartType ...string) Series {
 	s := Series{
 		Data: NewSeriesDataFromValues(values),
@@ -54,6 +56,7 @@ func NewSeriesFromValues(values []float64, chartType ...string) Series {
 	return s
 }
 
+// NewSeriesDataFromValues return a series data
 func NewSeriesDataFromValues(values []float64) []SeriesData {
 	data := make([]SeriesData, len(values))
 	for index, value := range values {
@@ -204,13 +207,19 @@ func NewPieSeriesList(values []float64, opts ...PieSeriesOption) SeriesList {
 }
 
 type seriesSummary struct {
-	MaxIndex     int
-	MaxValue     float64
-	MinIndex     int
-	MinValue     float64
+	// The index of max value
+	MaxIndex int
+	// The max value
+	MaxValue float64
+	// The index of min value
+	MinIndex int
+	// The min value
+	MinValue float64
+	// THe average value
 	AverageValue float64
 }
 
+// Summary get summary of series
 func (s *Series) Summary() seriesSummary {
 	minIndex := -1
 	maxIndex := -1
@@ -237,6 +246,7 @@ func (s *Series) Summary() seriesSummary {
 	}
 }
 
+// Names returns the names of series list
 func (sl SeriesList) Names() []string {
 	names := make([]string, len(sl))
 	for index, s := range sl {
@@ -245,8 +255,10 @@ func (sl SeriesList) Names() []string {
 	return names
 }
 
+// LabelFormatter label formatter
 type LabelFormatter func(index int, value float64, percent float64) string
 
+// NewPieLabelFormatter returns a pie label formatter
 func NewPieLabelFormatter(seriesNames []string, layout string) LabelFormatter {
 	if len(layout) == 0 {
 		layout = "{b}: {d}"
@@ -254,13 +266,15 @@ func NewPieLabelFormatter(seriesNames []string, layout string) LabelFormatter {
 	return NewLabelFormatter(seriesNames, layout)
 }
 
-func NewValueLabelFormater(seriesNames []string, layout string) LabelFormatter {
+// NewValueLabelFormatter returns a value formatter
+func NewValueLabelFormatter(seriesNames []string, layout string) LabelFormatter {
 	if len(layout) == 0 {
 		layout = "{c}"
 	}
 	return NewLabelFormatter(seriesNames, layout)
 }
 
+// NewLabelFormatter returns a label formaatter
 func NewLabelFormatter(seriesNames []string, layout string) LabelFormatter {
 	return func(index int, value, percent float64) string {
 		// 如果无percent的则设置为<0
diff --git a/theme.go b/theme.go
index 26786b9..31c3bf8 100644
--- a/theme.go
+++ b/theme.go
@@ -220,6 +220,7 @@ func init() {
 	SetDefaultTheme(ThemeLight)
 }
 
+// SetDefaultTheme sets default theme
 func SetDefaultTheme(name string) {
 	defaultTheme = NewTheme(name)
 }
diff --git a/title.go b/title.go
index a805c55..5af4c39 100644
--- a/title.go
+++ b/title.go
@@ -84,6 +84,7 @@ type titlePainter struct {
 	opt *TitleOption
 }
 
+// NewTitlePainter returns a title renderer
 func NewTitlePainter(p *Painter, opt TitleOption) *titlePainter {
 	return &titlePainter{
 		p:   p,
diff --git a/xaxis.go b/xaxis.go
index bfb57cb..00636a5 100644
--- a/xaxis.go
+++ b/xaxis.go
@@ -53,6 +53,7 @@ type XAxisOption struct {
 
 const defaultXAxisHeight = 30
 
+// NewXAxisOption returns a x axis option
 func NewXAxisOption(data []string, boundaryGap ...*bool) XAxisOption {
 	opt := XAxisOption{
 		Data: data,
@@ -89,6 +90,7 @@ func (opt *XAxisOption) ToAxisOption() AxisOption {
 	return axisOpt
 }
 
+// NewBottomXAxis returns a bottom x axis renderer
 func NewBottomXAxis(p *Painter, opt XAxisOption) *axisPainter {
 	return NewAxisPainter(p, opt.ToAxisOption())
 }
diff --git a/yaxis.go b/yaxis.go
index 265ac59..b0bfa86 100644
--- a/yaxis.go
+++ b/yaxis.go
@@ -50,6 +50,7 @@ type YAxisOption struct {
 	isCategoryAxis bool
 }
 
+// NewYAxisOptions returns a y axis option
 func NewYAxisOptions(data []string, others ...[]string) []YAxisOption {
 	arr := [][]string{
 		data,
@@ -95,6 +96,7 @@ func (opt *YAxisOption) ToAxisOption() AxisOption {
 	return axisOpt
 }
 
+// NewLeftYAxis returns a left y axis renderer
 func NewLeftYAxis(p *Painter, opt YAxisOption) *axisPainter {
 	p = p.Child(PainterPaddingOption(Box{
 		Bottom: defaultXAxisHeight,
@@ -102,6 +104,7 @@ func NewLeftYAxis(p *Painter, opt YAxisOption) *axisPainter {
 	return NewAxisPainter(p, opt.ToAxisOption())
 }
 
+// NewRightYAxis returns a right y axis renderer
 func NewRightYAxis(p *Painter, opt YAxisOption) *axisPainter {
 	p = p.Child(PainterPaddingOption(Box{
 		Bottom: defaultXAxisHeight,