chart

package module
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 Go to latest Published: Aug 12, 2016 License: MIT Imports: 15 Imported by: 0

README

go-chart

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Package chart is a very simple golang native charting library that supports timeseries and continuous line charts.

The v1.0 release has been tagged so things should be more or less stable, if something changes please log an issue.

Master should now be on the v2.x codebase, which brings a couple new features and better handling of basics like axes labeling etc. Per usual, see _examples for more information.

Installation

To install chart run the following:

> go get -u github.com/wcharczuk/go-chart

Most of the components are interchangeable so feel free to crib whatever you want.

Output Examples

Spark Lines:

Single axis:

Two axis:

Other Chart Types

Pie Chart:

The code for this chart can be found in _examples/pie_chart/main.go.

Stacked Bar:

The code for this chart can be found in _examples/stacked_bar/main.go.

Code Examples

Actual chart configurations and examples can be found in the ./_examples/ directory. They are web servers, so start them with go run main.go then access http://localhost:8080 to see the output.

Usage

Everything starts with the chart.Chart object. The bare minimum to draw a chart would be the following:


import (
    ...
    "bytes"
    ...
    "github.com/wcharczuk/go-chart" //exposes "chart"
)

graph := chart.Chart{
    Series: []chart.Series{
        chart.ContinuousSeries{
            XValues: []float64{1.0, 2.0, 3.0, 4.0},
            YValues: []float64{1.0, 2.0, 3.0, 4.0},
        },
    },
}

buffer := bytes.NewBuffer([]byte{})
err := graph.Render(chart.PNG, buffer)

Explanation of the above: A chart can have many Series, a Series is a collection of things that need to be drawn according to the X range and the Y range(s).

Here, we have a single series with x range values as float64s, rendered to a PNG. Note; we can pass any type of io.Writer into Render(...), meaning that we can render the chart to a file or a resonse or anything else that implements io.Writer.

API Overview

Everything on the chart.Chart object has defaults that can be overriden. Whenever a developer sets a property on the chart object, it is to be assumed that value will be used instead of the default. One complication here is any object's root chart.Style object (i.e named Style) and the Show property specifically, if any other property is set and the Show property is unset, it is assumed to be it's default value of False.

The best way to see the api in action is to look at the examples in the ./_examples/ directory.

Design Philosophy

I wanted to make a charting library that used only native golang, that could be stood up on a server (i.e. it had built in fonts).

The goal with the API itself is to have the "zero value be useful", and to require the user to not code more than they absolutely needed.

Contributions

This library is super early but contributions are welcome.

Documentation

Index

Constants

View Source 
const (
	// AllDaysMask is a bitmask of all the days of the week.
	AllDaysMask = 1<<uint(time.Sunday) | 1<<uint(time.Monday) | 1<<uint(time.Tuesday) | 1<<uint(time.Wednesday) | 1<<uint(time.Thursday) | 1<<uint(time.Friday) | 1<<uint(time.Saturday)
	// WeekDaysMask is a bitmask of all the weekdays of the week.
	WeekDaysMask = 1<<uint(time.Monday) | 1<<uint(time.Tuesday) | 1<<uint(time.Wednesday) | 1<<uint(time.Thursday) | 1<<uint(time.Friday)
	//WeekendDaysMask is a bitmask of the weekend days of the week.
	WeekendDaysMask = 1<<uint(time.Sunday) | 1<<uint(time.Saturday)
)
View Source 
const (
	// DefaultChartHeight is the default chart height.
	DefaultChartHeight = 400
	// DefaultChartWidth is the default chart width.
	DefaultChartWidth = 1024
	// DefaultStrokeWidth is the default chart line/stroke width.
	DefaultStrokeWidth = 1.0
	// DefaultAxisLineWidth is the line width of the axis lines.
	DefaultAxisLineWidth = 1.0
	//DefaultDPI is the default dots per inch for the chart.
	DefaultDPI = 92.0
	// DefaultMinimumFontSize is the default minimum font size.
	DefaultMinimumFontSize = 8.0
	// DefaultFontSize is the default font size.
	DefaultFontSize = 10.0
	// DefaultTitleFontSize is the default title font size.
	DefaultTitleFontSize = 18.0
	// DefaultAnnotationDeltaWidth is the width of the left triangle out of annotations.
	DefaultAnnotationDeltaWidth = 10
	// DefaultAnnotationFontSize is the font size of annotations.
	DefaultAnnotationFontSize = 10.0
	// DefaultAxisFontSize is the font size of the axis labels.
	DefaultAxisFontSize = 10.0
	// DefaultTitleTop is the default distance from the top of the chart to put the title.
	DefaultTitleTop = 10

	// DefaultLineSpacing is the default vertical distance between lines of text.
	DefaultLineSpacing = 5

	// DefaultYAxisMargin is the default distance from the right of the canvas to the y axis labels.
	DefaultYAxisMargin = 10
	// DefaultXAxisMargin is the default distance from bottom of the canvas to the x axis labels.
	DefaultXAxisMargin = 10

	//DefaultVerticalTickHeight is half the margin.
	DefaultVerticalTickHeight = DefaultXAxisMargin >> 1
	//DefaultHorizontalTickWidth is half the margin.
	DefaultHorizontalTickWidth = DefaultYAxisMargin >> 1

	// DefaultTickCount is the default number of ticks to show
	DefaultTickCount = 10
	// DefaultTickCountSanityCheck is a hard limit on number of ticks to prevent infinite loops.
	DefaultTickCountSanityCheck = 1 << 10 //1024

	// DefaultMinimumTickHorizontalSpacing is the minimum distance between horizontal ticks.
	DefaultMinimumTickHorizontalSpacing = 20
	// DefaultMinimumTickVerticalSpacing is the minimum distance between vertical ticks.
	DefaultMinimumTickVerticalSpacing = 20

	// DefaultDateFormat is the default date format.
	DefaultDateFormat = "2006-01-02"
	// DefaultDateHourFormat is the date format for hour timestamp formats.
	DefaultDateHourFormat = "01-02 3PM"
	// DefaultDateMinuteFormat is the date format for minute range timestamp formats.
	DefaultDateMinuteFormat = "01-02 3:04PM"
	// DefaultFloatFormat is the default float format.
	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
)
View Source 
const (
	// DefaultMACDPeriodPrimary is the long window.
	DefaultMACDPeriodPrimary = 26
	// DefaultMACDPeriodSecondary is the short window.
	DefaultMACDPeriodSecondary = 12
	// DefaultMACDSignalPeriod is the signal period to compute for the MACD.
	DefaultMACDSignalPeriod = 9
)
View Source 
const (
	// DefaultEMAPeriod is the default EMA period used in the sigma calculation.
	DefaultEMAPeriod = 12
)
View Source 
const (
	// DefaultSimpleMovingAveragePeriod is the default number of values to average.
	DefaultSimpleMovingAveragePeriod = 16
)

Variables

View Source 
var (
	// DaysOfWeek are all the time.Weekday in an array for utility purposes.
	DaysOfWeek = []time.Weekday{
		time.Sunday,
		time.Monday,
		time.Tuesday,
		time.Wednesday,
		time.Thursday,
		time.Friday,
		time.Saturday,
	}

	// WeekDays are the business time.Weekday in an array.
	WeekDays = []time.Weekday{
		time.Monday,
		time.Tuesday,
		time.Wednesday,
		time.Thursday,
		time.Friday,
	}

	// WeekendDays are the weekend time.Weekday in an array.
	WeekendDays = []time.Weekday{
		time.Sunday,
		time.Saturday,
	}

	//Epoch is unix epoc saved for utility purposes.
	Epoch = time.Unix(0, 0)
)
View Source 
var (
	// NYSEOpen is when the NYSE opens.
	NYSEOpen = Date.Time(9, 30, 0, 0, Date.Eastern())

	// NYSEClose is when the NYSE closes.
	NYSEClose = Date.Time(16, 0, 0, 0, Date.Eastern())

	// NASDAQOpen is when NASDAQ opens.
	NASDAQOpen = Date.Time(9, 30, 0, 0, Date.Eastern())

	// NASDAQClose is when NASDAQ closes.
	NASDAQClose = Date.Time(16, 0, 0, 0, Date.Eastern())

	// NYSEArcaOpen is when NYSEARCA opens.
	NYSEArcaOpen = Date.Time(4, 0, 0, 0, Date.Eastern())

	// NYSEArcaClose is when NYSEARCA closes.
	NYSEArcaClose = Date.Time(20, 0, 0, 0, Date.Eastern())
)
View Source 
var (
	// ColorWhite is white.
	ColorWhite = drawing.Color{R: 255, G: 255, B: 255, A: 255}
	// ColorBlue is the basic theme blue color.
	ColorBlue = drawing.Color{R: 0, G: 116, B: 217, A: 255}
	// ColorCyan is the basic theme cyan color.
	ColorCyan = drawing.Color{R: 0, G: 217, B: 210, A: 255}
	// ColorGreen is the basic theme green color.
	ColorGreen = drawing.Color{R: 0, G: 217, B: 101, A: 255}
	// ColorRed is the basic theme red color.
	ColorRed = drawing.Color{R: 217, G: 0, B: 116, A: 255}
	// ColorOrange is the basic theme orange color.
	ColorOrange = drawing.Color{R: 217, G: 101, B: 0, A: 255}
	// ColorYellow is the basic theme yellow color.
	ColorYellow = drawing.Color{R: 217, G: 210, B: 0, A: 255}
	// ColorBlack is the basic theme black color.
	ColorBlack = drawing.Color{R: 51, G: 51, B: 51, A: 255}
	// ColorLightGray is the basic theme light gray color.
	ColorLightGray = drawing.Color{R: 239, G: 239, B: 239, A: 255}

	// ColorAlternateBlue is a alternate theme color.
	ColorAlternateBlue = drawing.Color{R: 106, G: 195, B: 203, A: 255}
	// ColorAlternateGreen is a alternate theme color.
	ColorAlternateGreen = drawing.Color{R: 42, G: 190, B: 137, A: 255}
	// ColorAlternateGray is a alternate theme color.
	ColorAlternateGray = drawing.Color{R: 110, G: 128, B: 139, A: 255}
	// ColorAlternateYellow is a alternate theme color.
	ColorAlternateYellow = drawing.Color{R: 240, G: 174, B: 90, A: 255}
	// ColorAlternateLightGray is a alternate theme color.
	ColorAlternateLightGray = drawing.Color{R: 187, G: 190, B: 191, A: 255}
)
View Source 
var (
	// DefaultBackgroundColor is the default chart background color.
	// It is equivalent to css color:white.
	DefaultBackgroundColor = ColorWhite
	// DefaultBackgroundStrokeColor is the default chart border color.
	// It is equivalent to color:white.
	DefaultBackgroundStrokeColor = ColorWhite
	// DefaultCanvasColor is the default chart canvas color.
	// It is equivalent to css color:white.
	DefaultCanvasColor = ColorWhite
	// DefaultCanvasStrokeColor is the default chart canvas stroke color.
	// It is equivalent to css color:white.
	DefaultCanvasStrokeColor = ColorWhite
	// DefaultTextColor is the default chart text color.
	// It is equivalent to #333333.
	DefaultTextColor = ColorBlack
	// DefaultAxisColor is the default chart axis line color.
	// It is equivalent to #333333.
	DefaultAxisColor = ColorBlack
	// DefaultStrokeColor is the default chart border color.
	// It is equivalent to #efefef.
	DefaultStrokeColor = ColorLightGray
	// DefaultFillColor is the default fill color.
	// It is equivalent to #0074d9.
	DefaultFillColor = ColorBlue
	// DefaultAnnotationFillColor is the default annotation background color.
	DefaultAnnotationFillColor = ColorWhite
	// DefaultGridLineColor is the default grid line color.
	DefaultGridLineColor = ColorLightGray
)
View Source 
var (
	// DefaultColors are a couple default series colors.
	DefaultColors = []drawing.Color{
		ColorBlue,
		ColorGreen,
		ColorRed,
		ColorCyan,
		ColorOrange,
	}

	// DefaultAlternateColors are a couple alternate colors.
	DefaultAlternateColors = []drawing.Color{
		ColorAlternateBlue,
		ColorAlternateGreen,
		ColorAlternateGray,
		ColorAlternateYellow,
		ColorBlue,
		ColorGreen,
		ColorRed,
		ColorCyan,
		ColorOrange,
	}
)
View Source 
var (
	// DashArrayDots is a dash array that represents '....' style stroke dashes.
	DashArrayDots = []int{1, 1}
	// DashArrayDashesSmall is a dash array that represents '- - -' style stroke dashes.
	DashArrayDashesSmall = []int{3, 3}
	// DashArrayDashesMedium is a dash array that represents '-- -- --' style stroke dashes.
	DashArrayDashesMedium = []int{5, 5}
	// DashArrayDashesLarge is a dash array that represents '----- ----- -----' style stroke dashes.
	DashArrayDashesLarge = []int{10, 10}
)
View Source 
var (
	// DefaultAnnotationPadding is the padding around an annotation.
	DefaultAnnotationPadding = Box{Top: 5, Left: 5, Right: 5, Bottom: 5}
	// DefaultBackgroundPadding is the default canvas padding config.
	DefaultBackgroundPadding = Box{Top: 5, Left: 5, Right: 5, Bottom: 5}
)
View Source 
var (
	// Date contains utility functions that operate on dates.
	Date = &date{}
)
View Source 
var (
	// Draw contains helpers for drawing common objects.
	Draw = &draw{}
)
View Source 
var (
	// Math contains helper methods for common math operations.
	Math = &mathUtil{}
)
View Source 
var (
	// Sequence contains some sequence utilities.
	// These utilities can be useful for generating test data.
	Sequence = &sequence{}
)
View Source 
var (
	// Text contains utilities for text.
	Text = &text{}
)

Functions

func Float64ToTime 

func Float64ToTime(tf float64) time.Time

Float64ToTime returns a time from a float64.

func FloatValueFormatter 

func FloatValueFormatter(v interface{}) string

FloatValueFormatter is a ValueFormatter for float64.

func FloatValueFormatterWithFormat 

func FloatValueFormatterWithFormat(v interface{}, floatFormat string) string

FloatValueFormatterWithFormat is a ValueFormatter for float64 with a given format.

func GetAlternateColor 

func GetAlternateColor(index int) drawing.Color

GetAlternateColor returns a color from the default list by index. NOTE: the index will wrap around (using a modulo).

func GetDefaultColor 

func GetDefaultColor(index int) drawing.Color

GetDefaultColor returns a color from the default list by index. NOTE: the index will wrap around (using a modulo).

func GetDefaultFont 

func GetDefaultFont() (*truetype.Font, error)

GetDefaultFont returns the default font (Roboto-Medium).

func PercentValueFormatter 

func PercentValueFormatter(v interface{}) string

PercentValueFormatter is a formatter for percent values. NOTE: it normalizes the values, i.e. multiplies by 100.0.

func TimeHourValueFormatter 

func TimeHourValueFormatter(v interface{}) string

TimeHourValueFormatter is a ValueFormatter for timestamps.

func TimeMinuteValueFormatter 

func TimeMinuteValueFormatter(v interface{}) string

TimeMinuteValueFormatter is a ValueFormatter for timestamps.

func TimeToFloat64 

func TimeToFloat64(t time.Time) float64

TimeToFloat64 returns a float64 representation of a time.

func TimeValueFormatter 

func TimeValueFormatter(v interface{}) string

TimeValueFormatter is a ValueFormatter for timestamps.

func TimeValueFormatterWithFormat 

func TimeValueFormatterWithFormat(v interface{}, dateFormat string) string

TimeValueFormatterWithFormat is a ValueFormatter for timestamps with a given format.

Types

type AnnotationSeries 

type AnnotationSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	Annotations []Value2
}

AnnotationSeries is a series of labels on the chart.

func LastValueAnnotation 

func LastValueAnnotation(innerSeries ValueProvider, vfs ...ValueFormatter) AnnotationSeries

LastValueAnnotation returns an annotation series of just the last value of a value provider.

func (AnnotationSeries) GetName 

func (as AnnotationSeries) GetName() string

GetName returns the name of the time series.

func (AnnotationSeries) GetStyle 

func (as AnnotationSeries) GetStyle() Style

GetStyle returns the line style.

func (AnnotationSeries) GetYAxis 

func (as AnnotationSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (AnnotationSeries) Measure 

func (as AnnotationSeries) Measure(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) Box

Measure returns a bounds box of the series.

func (AnnotationSeries) Render 

func (as AnnotationSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render draws the series.

type Axis 

type Axis interface {
	GetName() string
	GetStyle() Style

	GetTicks() []Tick
	GenerateTicks(r Renderer, ra Range, vf ValueFormatter) []Tick

	// GetGridLines returns the gridlines for the axis.
	GetGridLines(ticks []Tick) []GridLine

	// Measure should return an absolute box for the axis.
	// This is used when auto-fitting the canvas to the background.
	Measure(r Renderer, canvasBox Box, ra Range, style Style, ticks []Tick) Box

	// Render renders the axis.
	Render(r Renderer, canvasBox Box, ra Range, style Style, ticks []Tick)
}

Axis is a chart feature detailing what values happen where.

type BarChart 

type BarChart struct {
	Title      string
	TitleStyle Style

	Width  int
	Height int
	DPI    float64

	BarWidth int

	Background Style
	Canvas     Style

	XAxis Style
	YAxis YAxis

	BarSpacing int

	Font *truetype.Font

	Bars     []Value
	Elements []Renderable
	// contains filtered or unexported fields
}

BarChart is a chart that draws bars on a range.

func (BarChart) GetBarSpacing 

func (bc BarChart) GetBarSpacing() int

GetBarSpacing returns the spacing between bars.

func (BarChart) GetBarWidth 

func (bc BarChart) GetBarWidth() int

GetBarWidth returns the default bar width.

func (BarChart) GetDPI 

func (bc BarChart) GetDPI() float64

GetDPI returns the dpi for the chart.

func (BarChart) GetFont 

func (bc BarChart) GetFont() *truetype.Font

GetFont returns the text font.

func (BarChart) GetHeight 

func (bc BarChart) GetHeight() int

GetHeight returns the chart height or the default value.

func (BarChart) GetWidth 

func (bc BarChart) GetWidth() int

GetWidth returns the chart width or the default value.

func (BarChart) Render 

func (bc BarChart) Render(rp RendererProvider, w io.Writer) error

Render renders the chart with the given renderer to the given io.Writer.

type BollingerBandsSeries 

type BollingerBandsSeries struct {
	Name  string
	Style Style
	YAxis YAxisType

	Period      int
	K           float64
	InnerSeries ValueProvider
	// contains filtered or unexported fields
}

BollingerBandsSeries draws bollinger bands for an inner series. Bollinger bands are defined by two lines, one at SMA+k*stddev, one at SMA-k*stdev.

func (*BollingerBandsSeries) GetBoundedLastValue 

func (bbs *BollingerBandsSeries) GetBoundedLastValue() (x, y1, y2 float64)

GetBoundedLastValue returns the last bounded value for the series.

func (*BollingerBandsSeries) GetBoundedValue 

func (bbs *BollingerBandsSeries) GetBoundedValue(index int) (x, y1, y2 float64)

GetBoundedValue gets the bounded value for the series.

func (BollingerBandsSeries) GetK 

func (bbs BollingerBandsSeries) GetK(defaults ...float64) float64

GetK returns the K value.

func (BollingerBandsSeries) GetName 

func (bbs BollingerBandsSeries) GetName() string

GetName returns the name of the time series.

func (BollingerBandsSeries) GetPeriod 

func (bbs BollingerBandsSeries) GetPeriod() int

GetPeriod returns the window size.

func (BollingerBandsSeries) GetStyle 

func (bbs BollingerBandsSeries) GetStyle() Style

GetStyle returns the line style.

func (BollingerBandsSeries) GetYAxis 

func (bbs BollingerBandsSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (*BollingerBandsSeries) Len 

func (bbs *BollingerBandsSeries) Len() int

Len returns the number of elements in the series.

func (*BollingerBandsSeries) Render 

func (bbs *BollingerBandsSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type BoundedLastValueProvider 

type BoundedLastValueProvider interface {
	GetBoundedLastValue() (x, y1, y2 float64)
}

BoundedLastValueProvider is a special type of value provider that can return it's (potentially computed) bounded last value.

type BoundedValueProvider 

type BoundedValueProvider interface {
	Len() int
	GetBoundedValue(index int) (x, y1, y2 float64)
}

BoundedValueProvider allows series to return a range.

type Box 

type Box struct {
	Top    int
	Left   int
	Right  int
	Bottom int
}

Box represents the main 4 dimensions of a box.

func (Box) Aspect 

func (b Box) Aspect() float64

Aspect returns the aspect ratio of the box.

func (Box) Center 

func (b Box) Center() (x, y int)

Center returns the center of the box

func (Box) Clone 

func (b Box) Clone() Box

Clone returns a new copy of the box.

func (Box) Constrain 

func (b Box) Constrain(other Box) Box

Constrain is similar to `Fit` except that it will work more literally like the opposite of grow.

func (Box) Equals 

func (b Box) Equals(other Box) bool

Equals returns if the box equals another box.

func (Box) Fit 

func (b Box) Fit(other Box) Box

Fit is functionally the inverse of grow. Fit maintains the original aspect ratio of the `other` box, but constrains it to the bounds of the target box.

func (Box) GetBottom 

func (b Box) GetBottom(defaults ...int) int

GetBottom returns a coalesced value with a default.

func (Box) GetLeft 

func (b Box) GetLeft(defaults ...int) int

GetLeft returns a coalesced value with a default.

func (Box) GetRight 

func (b Box) GetRight(defaults ...int) int

GetRight returns a coalesced value with a default.

func (Box) GetTop 

func (b Box) GetTop(defaults ...int) int

GetTop returns a coalesced value with a default.

func (Box) Grow 

func (b Box) Grow(other Box) Box

Grow grows a box based on another box.

func (Box) Height 

func (b Box) Height() int

Height returns the height

func (Box) IsBiggerThan 

func (b Box) IsBiggerThan(other Box) bool

IsBiggerThan returns if a box is bigger than another box.

func (Box) IsSmallerThan 

func (b Box) IsSmallerThan(other Box) bool

IsSmallerThan returns if a box is smaller than another box.

func (Box) IsZero 

func (b Box) IsZero() bool

IsZero returns if the box is set or not.

func (Box) OuterConstrain 

func (b Box) OuterConstrain(bounds, other Box) Box

OuterConstrain is similar to `Constraint` with the difference that it applies corrections

func (Box) Shift 

func (b Box) Shift(x, y int) Box

Shift pushes a box by x,y.

func (Box) String 

func (b Box) String() string

String returns a string representation of the box.

func (Box) Width 

func (b Box) Width() int

Width returns the width

type Chart 

type Chart struct {
	Title      string
	TitleStyle Style

	Width  int
	Height int
	DPI    float64

	Background Style
	Canvas     Style

	XAxis          XAxis
	YAxis          YAxis
	YAxisSecondary YAxis

	Font *truetype.Font

	Series   []Series
	Elements []Renderable
	// contains filtered or unexported fields
}

Chart is what we're drawing.

func (Chart) Box 

func (c Chart) Box() Box

Box returns the chart bounds as a box.

func (Chart) GetDPI 

func (c Chart) GetDPI(defaults ...float64) float64

GetDPI returns the dpi for the chart.

func (Chart) GetFont 

func (c Chart) GetFont() *truetype.Font

GetFont returns the text font.

func (Chart) GetHeight 

func (c Chart) GetHeight() int

GetHeight returns the chart height or the default value.

func (Chart) GetWidth 

func (c Chart) GetWidth() int

GetWidth returns the chart width or the default value.

func (Chart) Render 

func (c Chart) Render(rp RendererProvider, w io.Writer) error

Render renders the chart with the given renderer to the given io.Writer.

type ConcatSeries 

type ConcatSeries []Series

ConcatSeries is a special type of series that concatenates its `InnerSeries`.

func (ConcatSeries) GetValue 

func (cs ConcatSeries) GetValue(index int) (x, y float64)

GetValue returns the value at the (meta) index (i.e 0 => totalLen-1)

func (ConcatSeries) Len 

func (cs ConcatSeries) Len() int

Len returns the length of the concatenated set of series.

type ContinuousRange 

type ContinuousRange struct {
	Min    float64
	Max    float64
	Domain int
}

ContinuousRange represents a boundary for a set of numbers.

func (ContinuousRange) GetDelta 

func (r ContinuousRange) GetDelta() float64

GetDelta returns the difference between the min and max value.

func (ContinuousRange) GetDomain 

func (r ContinuousRange) GetDomain() int

GetDomain returns the range domain.

func (ContinuousRange) GetMax 

func (r ContinuousRange) GetMax() float64

GetMax returns the max value for the continuous range.

func (ContinuousRange) GetMin 

func (r ContinuousRange) GetMin() float64

GetMin gets the min value for the continuous range.

func (ContinuousRange) IsZero 

func (r ContinuousRange) IsZero() bool

IsZero returns if the ContinuousRange has been set or not.

func (*ContinuousRange) SetDomain 

func (r *ContinuousRange) SetDomain(domain int)

SetDomain sets the range domain.

func (*ContinuousRange) SetMax 

func (r *ContinuousRange) SetMax(max float64)

SetMax sets the max value for the continuous range.

func (*ContinuousRange) SetMin 

func (r *ContinuousRange) SetMin(min float64)

SetMin sets the min value for the continuous range.

func (ContinuousRange) String 

func (r ContinuousRange) String() string

String returns a simple string for the ContinuousRange.

func (ContinuousRange) Translate 

func (r ContinuousRange) Translate(value float64) int

Translate maps a given value into the ContinuousRange space.

type ContinuousSeries 

type ContinuousSeries struct {
	Name  string
	Style Style

	YAxis YAxisType

	XValues []float64
	YValues []float64
}

ContinuousSeries represents a line on a chart.

func (ContinuousSeries) GetLastValue 

func (cs ContinuousSeries) GetLastValue() (float64, float64)

GetLastValue gets the last value.

func (ContinuousSeries) GetName 

func (cs ContinuousSeries) GetName() string

GetName returns the name of the time series.

func (ContinuousSeries) GetStyle 

func (cs ContinuousSeries) GetStyle() Style

GetStyle returns the line style.

func (ContinuousSeries) GetValue 

func (cs ContinuousSeries) GetValue(index int) (float64, float64)

GetValue gets a value at a given index.

func (ContinuousSeries) GetValueFormatters 

func (cs ContinuousSeries) GetValueFormatters() (x, y ValueFormatter)

GetValueFormatters returns value formatter defaults for the series.

func (ContinuousSeries) GetYAxis 

func (cs ContinuousSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (ContinuousSeries) Len 

func (cs ContinuousSeries) Len() int

Len returns the number of elements in the series.

func (ContinuousSeries) Render 

func (cs ContinuousSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type EMASeries 

type EMASeries struct {
	Name  string
	Style Style
	YAxis YAxisType

	Period      int
	InnerSeries ValueProvider
	// contains filtered or unexported fields
}

EMASeries is a computed series.

func (*EMASeries) GetLastValue 

func (ema *EMASeries) GetLastValue() (x, y float64)

GetLastValue computes the last moving average value but walking back window size samples, and recomputing the last moving average chunk.

func (EMASeries) GetName 

func (ema EMASeries) GetName() string

GetName returns the name of the time series.

func (EMASeries) GetPeriod 

func (ema EMASeries) GetPeriod() int

GetPeriod returns the window size.

func (EMASeries) GetSigma 

func (ema EMASeries) GetSigma() float64

GetSigma returns the smoothing factor for the serise.

func (EMASeries) GetStyle 

func (ema EMASeries) GetStyle() Style

GetStyle returns the line style.

func (*EMASeries) GetValue 

func (ema *EMASeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (EMASeries) GetYAxis 

func (ema EMASeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (EMASeries) Len 

func (ema EMASeries) Len() int

Len returns the number of elements in the series.

func (*EMASeries) Render 

func (ema *EMASeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type FullBoundedValueProvider 

type FullBoundedValueProvider interface {
	BoundedValueProvider
	BoundedLastValueProvider
}

FullBoundedValueProvider is an interface that combines `BoundedValueProvider` and `BoundedLastValueProvider`

type FullValueProvider 

type FullValueProvider interface {
	ValueProvider
	LastValueProvider
}

FullValueProvider is an interface that combines `ValueProvider` and `LastValueProvider`

type GridLine 

type GridLine struct {
	IsMinor bool
	Style   Style
	Value   float64
}

GridLine is a line on a graph canvas.

func GenerateGridLines 

func GenerateGridLines(ticks []Tick, majorStyle, minorStyle Style) []GridLine

GenerateGridLines generates grid lines.

func (GridLine) Major 

func (gl GridLine) Major() bool

Major returns if the gridline is a `major` line.

func (GridLine) Minor 

func (gl GridLine) Minor() bool

Minor returns if the gridline is a `minor` line.

func (GridLine) Render 

func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range, isVertical bool, defaults Style)

Render renders the gridline

type GridLineProvider 

type GridLineProvider interface {
	GetGridLines(ticks []Tick, isVertical bool, majorStyle, minorStyle Style) []GridLine
}

GridLineProvider is a type that provides grid lines.

type HistogramSeries 

type HistogramSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider
}

HistogramSeries is a special type of series that draws as a histogram. Some peculiarities; it will always be lower bounded at 0 (at the very least). This may alter ranges a bit and generally you want to put a histogram series on it's own y-axis.

func (HistogramSeries) GetBoundedValue 

func (hs HistogramSeries) GetBoundedValue(index int) (x, y1, y2 float64)

GetBoundedValue implements BoundedValueProvider.GetBoundedValue

func (HistogramSeries) GetName 

func (hs HistogramSeries) GetName() string

GetName implements Series.GetName.

func (HistogramSeries) GetStyle 

func (hs HistogramSeries) GetStyle() Style

GetStyle implements Series.GetStyle.

func (HistogramSeries) GetValue 

func (hs HistogramSeries) GetValue(index int) (x, y float64)

GetValue implements ValueProvider.GetValue.

func (HistogramSeries) GetYAxis 

func (hs HistogramSeries) GetYAxis() YAxisType

GetYAxis returns which yaxis the series is mapped to.

func (HistogramSeries) Len 

func (hs HistogramSeries) Len() int

Len implements BoundedValueProvider.Len.

func (HistogramSeries) Render 

func (hs HistogramSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render implements Series.Render.

type HolidayProvider 

type HolidayProvider func(time.Time) bool

HolidayProvider is a function that returns if a given time falls on a holiday.

type IsZeroable 

type IsZeroable interface {
	IsZero() bool
}

IsZeroable is a type that returns if it's been set or not.

type LastValueProvider 

type LastValueProvider interface {
	GetLastValue() (x, y float64)
}

LastValueProvider is a special type of value provider that can return it's (potentially computed) last value.

type LinearRegressionSeries 

type LinearRegressionSeries struct {
	Name  string
	Style Style
	YAxis YAxisType

	Window      int
	Offset      int
	InnerSeries ValueProvider
	// contains filtered or unexported fields
}

LinearRegressionSeries is a series that plots the n-nearest neighbors linear regression for the values.

func (LinearRegressionSeries) GetEndIndex 

func (lrs LinearRegressionSeries) GetEndIndex() int

GetEndIndex returns the effective window end.

func (*LinearRegressionSeries) GetLastValue 

func (lrs *LinearRegressionSeries) GetLastValue() (x, y float64)

GetLastValue computes the last moving average value but walking back window size samples, and recomputing the last moving average chunk.

func (LinearRegressionSeries) GetName 

func (lrs LinearRegressionSeries) GetName() string

GetName returns the name of the time series.

func (LinearRegressionSeries) GetOffset 

func (lrs LinearRegressionSeries) GetOffset() int

GetOffset returns the data offset.

func (LinearRegressionSeries) GetStyle 

func (lrs LinearRegressionSeries) GetStyle() Style

GetStyle returns the line style.

func (*LinearRegressionSeries) GetValue 

func (lrs *LinearRegressionSeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (LinearRegressionSeries) GetWindow 

func (lrs LinearRegressionSeries) GetWindow() int

GetWindow returns the window size.

func (LinearRegressionSeries) GetYAxis 

func (lrs LinearRegressionSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (LinearRegressionSeries) Len 

func (lrs LinearRegressionSeries) Len() int

Len returns the number of elements in the series.

func (*LinearRegressionSeries) Render 

func (lrs *LinearRegressionSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type MACDLineSeries 

type MACDLineSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider

	PrimaryPeriod   int
	SecondaryPeriod int

	Sigma float64
	// contains filtered or unexported fields
}

MACDLineSeries is a series that computes the inner ema1-ema2 value as a series.

func (MACDLineSeries) GetName 

func (macdl MACDLineSeries) GetName() string

GetName returns the name of the time series.

func (MACDLineSeries) GetPeriods 

func (macdl MACDLineSeries) GetPeriods() (w1, w2 int)

GetPeriods returns the primary and secondary periods.

func (MACDLineSeries) GetStyle 

func (macdl MACDLineSeries) GetStyle() Style

GetStyle returns the line style.

func (*MACDLineSeries) GetValue 

func (macdl *MACDLineSeries) GetValue(index int) (x float64, y float64)

GetValue gets a value at a given index. For MACD it is the signal value.

func (MACDLineSeries) GetYAxis 

func (macdl MACDLineSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (*MACDLineSeries) Len 

func (macdl *MACDLineSeries) Len() int

Len returns the number of elements in the series.

func (*MACDLineSeries) Render 

func (macdl *MACDLineSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type MACDSeries 

type MACDSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider

	PrimaryPeriod   int
	SecondaryPeriod int
	SignalPeriod    int
	// contains filtered or unexported fields
}

MACDSeries computes the difference between the MACD line and the MACD Signal line. It is used in technical analysis and gives a lagging indicator of momentum.

func (MACDSeries) GetName 

func (macd MACDSeries) GetName() string

GetName returns the name of the time series.

func (MACDSeries) GetPeriods 

func (macd MACDSeries) GetPeriods() (w1, w2, sig int)

GetPeriods returns the primary and secondary periods.

func (MACDSeries) GetStyle 

func (macd MACDSeries) GetStyle() Style

GetStyle returns the line style.

func (*MACDSeries) GetValue 

func (macd *MACDSeries) GetValue(index int) (x float64, y float64)

GetValue gets a value at a given index. For MACD it is the signal value.

func (MACDSeries) GetYAxis 

func (macd MACDSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (MACDSeries) Len 

func (macd MACDSeries) Len() int

Len returns the number of elements in the series.

type MACDSignalSeries 

type MACDSignalSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider

	PrimaryPeriod   int
	SecondaryPeriod int
	SignalPeriod    int
	// contains filtered or unexported fields
}

MACDSignalSeries computes the EMA of the MACDLineSeries.

func (MACDSignalSeries) GetName 

func (macds MACDSignalSeries) GetName() string

GetName returns the name of the time series.

func (MACDSignalSeries) GetPeriods 

func (macds MACDSignalSeries) GetPeriods() (w1, w2, sig int)

GetPeriods returns the primary and secondary periods.

func (MACDSignalSeries) GetStyle 

func (macds MACDSignalSeries) GetStyle() Style

GetStyle returns the line style.

func (*MACDSignalSeries) GetValue 

func (macds *MACDSignalSeries) GetValue(index int) (x float64, y float64)

GetValue gets a value at a given index. For MACD it is the signal value.

func (MACDSignalSeries) GetYAxis 

func (macds MACDSignalSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (*MACDSignalSeries) Len 

func (macds *MACDSignalSeries) Len() int

Len returns the number of elements in the series.

func (*MACDSignalSeries) Render 

func (macds *MACDSignalSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type MarketHoursRange 

type MarketHoursRange struct {
	Min time.Time
	Max time.Time

	MarketOpen  time.Time
	MarketClose time.Time

	HolidayProvider HolidayProvider

	ValueFormatter ValueFormatter

	Domain int
}

MarketHoursRange is a special type of range that compresses a time range into just the market (i.e. NYSE operating hours and days) range.

func (MarketHoursRange) GetDelta 

func (mhr MarketHoursRange) GetDelta() float64

GetDelta gets the delta.

func (MarketHoursRange) GetDomain 

func (mhr MarketHoursRange) GetDomain() int

GetDomain gets the domain.

func (MarketHoursRange) GetEffectiveMax 

func (mhr MarketHoursRange) GetEffectiveMax() time.Time

GetEffectiveMax gets either the close on the max, or the max itself.

func (MarketHoursRange) GetHolidayProvider 

func (mhr MarketHoursRange) GetHolidayProvider() HolidayProvider

GetHolidayProvider coalesces a userprovided holiday provider and the date.DefaultHolidayProvider.

func (MarketHoursRange) GetMarketClose 

func (mhr MarketHoursRange) GetMarketClose() time.Time

GetMarketClose returns the market close time.

func (MarketHoursRange) GetMarketOpen 

func (mhr MarketHoursRange) GetMarketOpen() time.Time

GetMarketOpen returns the market open time.

func (MarketHoursRange) GetMax 

func (mhr MarketHoursRange) GetMax() float64

GetMax returns the max value.

func (MarketHoursRange) GetMin 

func (mhr MarketHoursRange) GetMin() float64

GetMin returns the min value.

func (*MarketHoursRange) GetTicks 

func (mhr *MarketHoursRange) GetTicks(r Renderer, defaults Style, vf ValueFormatter) []Tick

GetTicks returns the ticks for the range. This is to override the default continous ticks that would be generated for the range.

func (MarketHoursRange) GetTimezone 

func (mhr MarketHoursRange) GetTimezone() *time.Location

GetTimezone returns the timezone for the market hours range.

func (MarketHoursRange) IsZero 

func (mhr MarketHoursRange) IsZero() bool

IsZero returns if the range is setup or not.

func (*MarketHoursRange) SetDomain 

func (mhr *MarketHoursRange) SetDomain(domain int)

SetDomain sets the domain.

func (*MarketHoursRange) SetMax 

func (mhr *MarketHoursRange) SetMax(max float64)

SetMax sets the max value.

func (*MarketHoursRange) SetMin 

func (mhr *MarketHoursRange) SetMin(min float64)

SetMin sets the min value.

func (MarketHoursRange) String 

func (mhr MarketHoursRange) String() string

func (MarketHoursRange) Translate 

func (mhr MarketHoursRange) Translate(value float64) int

Translate maps a given value into the ContinuousRange space.

type MaxSeries 

type MaxSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider
	// contains filtered or unexported fields
}

MaxSeries draws a horizontal line at the maximum value of the inner series.

func (MaxSeries) GetName 

func (ms MaxSeries) GetName() string

GetName returns the name of the time series.

func (MaxSeries) GetStyle 

func (ms MaxSeries) GetStyle() Style

GetStyle returns the line style.

func (*MaxSeries) GetValue 

func (ms *MaxSeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (MaxSeries) GetYAxis 

func (ms MaxSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (MaxSeries) Len 

func (ms MaxSeries) Len() int

Len returns the number of elements in the series.

func (*MaxSeries) Render 

func (ms *MaxSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type MinSeries 

type MinSeries struct {
	Name        string
	Style       Style
	YAxis       YAxisType
	InnerSeries ValueProvider
	// contains filtered or unexported fields
}

MinSeries draws a horizontal line at the minimum value of the inner series.

func (MinSeries) GetName 

func (ms MinSeries) GetName() string

GetName returns the name of the time series.

func (MinSeries) GetStyle 

func (ms MinSeries) GetStyle() Style

GetStyle returns the line style.

func (*MinSeries) GetValue 

func (ms *MinSeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (MinSeries) GetYAxis 

func (ms MinSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (MinSeries) Len 

func (ms MinSeries) Len() int

Len returns the number of elements in the series.

func (*MinSeries) Render 

func (ms *MinSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type NameProvider 

type NameProvider interface {
	GetName() string
}

NameProvider is a type that returns a name.

type PieChart 

type PieChart struct {
	Title      string
	TitleStyle Style

	Width  int
	Height int
	DPI    float64

	Background Style
	Canvas     Style
	SliceStyle Style

	Font *truetype.Font

	Values   []Value
	Elements []Renderable
	// contains filtered or unexported fields
}

PieChart is a chart that draws sections of a circle based on percentages.

func (PieChart) Box 

func (pc PieChart) Box() Box

Box returns the chart bounds as a box.

func (PieChart) GetDPI 

func (pc PieChart) GetDPI(defaults ...float64) float64

GetDPI returns the dpi for the chart.

func (PieChart) GetFont 

func (pc PieChart) GetFont() *truetype.Font

GetFont returns the text font.

func (PieChart) GetHeight 

func (pc PieChart) GetHeight() int

GetHeight returns the chart height or the default value.

func (PieChart) GetWidth 

func (pc PieChart) GetWidth() int

GetWidth returns the chart width or the default value.

func (PieChart) Render 

func (pc PieChart) Render(rp RendererProvider, w io.Writer) error

Render renders the chart with the given renderer to the given io.Writer.

type Range 

type Range interface {
	Stringable
	IsZeroable

	GetMin() float64
	SetMin(min float64)

	GetMax() float64
	SetMax(max float64)

	GetDelta() float64

	GetDomain() int
	SetDomain(domain int)

	// Translate the range to the domain.
	Translate(value float64) int
}

Range is a

type Renderable 

type Renderable func(r Renderer, canvasBox Box, defaults Style)

Renderable is a function that can be called to render custom elements on the chart.

func Legend 

func Legend(c *Chart, userDefaults ...Style) Renderable

Legend returns a legend renderable function.

type Renderer 

type Renderer interface {
	// GetDPI gets the DPI for the renderer.
	GetDPI() float64

	// SetDPI sets the DPI for the renderer.
	SetDPI(dpi float64)

	// SetStrokeColor sets the current stroke color.
	SetStrokeColor(drawing.Color)

	// SetFillColor sets the current fill color.
	SetFillColor(drawing.Color)

	// SetStrokeWidth sets the stroke width.
	SetStrokeWidth(width float64)

	// SetStrokeDashArray sets the stroke dash array.
	SetStrokeDashArray(dashArray []float64)

	// MoveTo moves the cursor to a given point.
	MoveTo(x, y int)

	// LineTo both starts a shape and draws a line to a given point
	// from the previous point.
	LineTo(x, y int)

	// QuadCurveTo draws a quad curve.
	// cx and cy represent the bezier "control points".
	QuadCurveTo(cx, cy, x, y int)

	// ArcTo draws an arc with a given center (cx,cy)
	// a given set of radii (rx,ry), a startAngle and delta (in radians).
	ArcTo(cx, cy int, rx, ry, startAngle, delta float64)

	// Close finalizes a shape as drawn by LineTo.
	Close()

	// Stroke strokes the path.
	Stroke()

	// Fill fills the path, but does not stroke.
	Fill()

	// FillStroke fills and strokes a path.
	FillStroke()

	// Circle draws a circle at the given coords with a given radius.
	Circle(radius float64, x, y int)

	// SetFont sets a font for a text field.
	SetFont(*truetype.Font)

	// SetFontColor sets a font's color
	SetFontColor(drawing.Color)

	// SetFontSize sets the font size for a text field.
	SetFontSize(size float64)

	// Text draws a text blob.
	Text(body string, x, y int)

	// MeasureText measures text.
	MeasureText(body string) Box

	// SetTextRotatation sets a rotation for drawing elements.
	SetTextRotation(radians float64)

	// ClearTextRotation clears rotation.
	ClearTextRotation()

	// Save writes the image to the given writer.
	Save(w io.Writer) error
}

Renderer represents the basic methods required to draw a chart.

func PNG 

func PNG(width, height int) (Renderer, error)

PNG returns a new png/raster renderer.

func SVG 

func SVG(width, height int) (Renderer, error)

SVG returns a new png/raster renderer.

type RendererProvider 

type RendererProvider func(int, int) (Renderer, error)

RendererProvider is a function that returns a renderer.

type RingBuffer 

type RingBuffer struct {
	// contains filtered or unexported fields
}

RingBuffer is a fifo buffer that is backed by a pre-allocated array, instead of allocating a whole new node object for each element (which saves GC churn). Enqueue can be O(n), Dequeue can be O(1).

func NewRingBuffer 

func NewRingBuffer() *RingBuffer

NewRingBuffer creates a new, empty, RingBuffer.

func NewRingBufferFromSlice 

func NewRingBufferFromSlice(values []interface{}) *RingBuffer

NewRingBufferFromSlice createsa ring buffer out of a slice.

func NewRingBufferWithCapacity 

func NewRingBufferWithCapacity(capacity int) *RingBuffer

NewRingBufferWithCapacity creates a new RingBuffer pre-allocated with the given capacity.

func (*RingBuffer) AsSlice 

func (rb *RingBuffer) AsSlice() []interface{}

AsSlice returns the ring buffer, in order, as a slice.

func (*RingBuffer) Average 

func (rb *RingBuffer) Average() float64

Average returns the float average of the values in the buffer.

func (*RingBuffer) Clear 

func (rb *RingBuffer) Clear()

Clear removes all objects from the RingBuffer.

func (*RingBuffer) Dequeue 

func (rb *RingBuffer) Dequeue() interface{}

Dequeue removes the first element from the RingBuffer.

func (*RingBuffer) Each 

func (rb *RingBuffer) Each(consumer func(value interface{}))

Each calls the consumer for each element in the buffer.

func (*RingBuffer) Enqueue 

func (rb *RingBuffer) Enqueue(object interface{})

Enqueue adds an element to the "back" of the RingBuffer.

func (*RingBuffer) Len 

func (rb *RingBuffer) Len() int

Len returns the length of the ring buffer (as it is currently populated). Actual memory footprint may be different.

func (*RingBuffer) Peek 

func (rb *RingBuffer) Peek() interface{}

Peek returns but does not remove the first element.

func (*RingBuffer) PeekBack 

func (rb *RingBuffer) PeekBack() interface{}

PeekBack returns but does not remove the last element.

func (*RingBuffer) StdDev 

func (rb *RingBuffer) StdDev() float64

StdDev returns the standard deviation.

func (*RingBuffer) String 

func (rb *RingBuffer) String() string

func (*RingBuffer) TotalLen 

func (rb *RingBuffer) TotalLen() int

TotalLen returns the total size of the ring bufffer, including empty elements.

func (*RingBuffer) TrimExcess 

func (rb *RingBuffer) TrimExcess()

TrimExcess resizes the buffer to better fit the contents.

func (*RingBuffer) Variance 

func (rb *RingBuffer) Variance() float64

Variance computes the variance of the buffer.

type SMASeries 

type SMASeries struct {
	Name  string
	Style Style
	YAxis YAxisType

	Period      int
	InnerSeries ValueProvider
}

SMASeries is a computed series.

func (SMASeries) GetLastValue 

func (sma SMASeries) GetLastValue() (x, y float64)

GetLastValue computes the last moving average value but walking back window size samples, and recomputing the last moving average chunk.

func (SMASeries) GetName 

func (sma SMASeries) GetName() string

GetName returns the name of the time series.

func (SMASeries) GetPeriod 

func (sma SMASeries) GetPeriod(defaults ...int) int

GetPeriod returns the window size.

func (SMASeries) GetStyle 

func (sma SMASeries) GetStyle() Style

GetStyle returns the line style.

func (SMASeries) GetValue 

func (sma SMASeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (SMASeries) GetYAxis 

func (sma SMASeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (SMASeries) Len 

func (sma SMASeries) Len() int

Len returns the number of elements in the series.

func (SMASeries) Render 

func (sma SMASeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type Series 

type Series interface {
	GetName() string
	GetYAxis() YAxisType
	GetStyle() Style
	Render(r Renderer, canvasBox Box, xrange, yrange Range, s Style)
}

Series is an alias to Renderable.

type StackedBar 

type StackedBar struct {
	Name   string
	Width  int
	Values []Value
}

StackedBar is a bar within a StackedBarChart.

func (StackedBar) GetWidth 

func (sb StackedBar) GetWidth() int

GetWidth returns the width of the bar.

type StackedBarChart 

type StackedBarChart struct {
	Title      string
	TitleStyle Style

	Width  int
	Height int
	DPI    float64

	Background Style
	Canvas     Style

	XAxis Style
	YAxis Style

	BarSpacing int

	Font *truetype.Font

	Bars     []StackedBar
	Elements []Renderable
	// contains filtered or unexported fields
}

StackedBarChart is a chart that draws sections of a bar based on percentages.

func (StackedBarChart) Box 

func (sbc StackedBarChart) Box() Box

Box returns the chart bounds as a box.

func (StackedBarChart) GetBarSpacing 

func (sbc StackedBarChart) GetBarSpacing() int

GetBarSpacing returns the spacing between bars.

func (StackedBarChart) GetDPI 

func (sbc StackedBarChart) GetDPI(defaults ...float64) float64

GetDPI returns the dpi for the chart.

func (StackedBarChart) GetFont 

func (sbc StackedBarChart) GetFont() *truetype.Font

GetFont returns the text font.

func (StackedBarChart) GetHeight 

func (sbc StackedBarChart) GetHeight() int

GetHeight returns the chart height or the default value.

func (StackedBarChart) GetWidth 

func (sbc StackedBarChart) GetWidth() int

GetWidth returns the chart width or the default value.

func (StackedBarChart) Render 

func (sbc StackedBarChart) Render(rp RendererProvider, w io.Writer) error

Render renders the chart with the given renderer to the given io.Writer.

type Stringable 

type Stringable interface {
	String() string
}

Stringable is a type that has a string representation.

type Style 

type Style struct {
	Show    bool
	Padding Box

	StrokeWidth     float64
	StrokeColor     drawing.Color
	StrokeDashArray []float64

	FillColor drawing.Color
	FontSize  float64
	FontColor drawing.Color
	Font      *truetype.Font

	TextHorizontalAlign TextHorizontalAlign
	TextVerticalAlign   TextVerticalAlign
	TextWrap            TextWrap
	TextLineSpacing     int
}

Style is a simple style set.

func StyleShow 

func StyleShow() Style

StyleShow is a prebuilt style with the `Show` property set to true.

func (Style) GetFillAndStrokeOptions 

func (s Style) GetFillAndStrokeOptions() Style

GetFillAndStrokeOptions returns the fill and stroke components.

func (Style) GetFillColor 

func (s Style) GetFillColor(defaults ...drawing.Color) drawing.Color

GetFillColor returns the fill color.

func (Style) GetFillOptions 

func (s Style) GetFillOptions() Style

GetFillOptions returns the fill components.

func (Style) GetFont 

func (s Style) GetFont(defaults ...*truetype.Font) *truetype.Font

GetFont returns the font face.

func (Style) GetFontColor 

func (s Style) GetFontColor(defaults ...drawing.Color) drawing.Color

GetFontColor gets the font size.

func (Style) GetFontSize 

func (s Style) GetFontSize(defaults ...float64) float64

GetFontSize gets the font size.

func (Style) GetPadding 

func (s Style) GetPadding(defaults ...Box) Box

GetPadding returns the padding.

func (Style) GetStrokeColor 

func (s Style) GetStrokeColor(defaults ...drawing.Color) drawing.Color

GetStrokeColor returns the stroke color.

func (Style) GetStrokeDashArray 

func (s Style) GetStrokeDashArray(defaults ...[]float64) []float64

GetStrokeDashArray returns the stroke dash array.

func (Style) GetStrokeOptions 

func (s Style) GetStrokeOptions() Style

GetStrokeOptions returns the stroke components.

func (Style) GetStrokeWidth 

func (s Style) GetStrokeWidth(defaults ...float64) float64

GetStrokeWidth returns the stroke width.

func (Style) GetTextHorizontalAlign 

func (s Style) GetTextHorizontalAlign(defaults ...TextHorizontalAlign) TextHorizontalAlign

GetTextHorizontalAlign returns the horizontal alignment.

func (Style) GetTextLineSpacing 

func (s Style) GetTextLineSpacing(defaults ...int) int

GetTextLineSpacing returns the spacing in pixels between lines of text (vertically).

func (Style) GetTextOptions 

func (s Style) GetTextOptions() Style

GetTextOptions returns just the text components of the style.

func (Style) GetTextVerticalAlign 

func (s Style) GetTextVerticalAlign(defaults ...TextVerticalAlign) TextVerticalAlign

GetTextVerticalAlign returns the vertical alignment.

func (Style) GetTextWrap 

func (s Style) GetTextWrap(defaults ...TextWrap) TextWrap

GetTextWrap returns the word wrap.

func (Style) InheritFrom 

func (s Style) InheritFrom(defaults Style) (final Style)

InheritFrom coalesces two styles into a new style.

func (Style) IsZero 

func (s Style) IsZero() bool

IsZero returns if the object is set or not.

func (Style) String 

func (s Style) String() string

String returns a text representation of the style.

func (Style) WriteDrawingOptionsToRenderer 

func (s Style) WriteDrawingOptionsToRenderer(r Renderer)

WriteDrawingOptionsToRenderer passes just the drawing style options to a renderer.

func (Style) WriteTextOptionsToRenderer 

func (s Style) WriteTextOptionsToRenderer(r Renderer)

WriteTextOptionsToRenderer passes just the text style options to a renderer.

func (Style) WriteToRenderer 

func (s Style) WriteToRenderer(r Renderer)

WriteToRenderer passes the style's options to a renderer.

type StyleProvider 

type StyleProvider interface {
	GetStyle() Style
}

StyleProvider is a type that returns a style.

type TextHorizontalAlign 

type TextHorizontalAlign int

TextHorizontalAlign is an enum for the horizontal alignment options. 

const (
	// TextHorizontalAlignUnset is the unset state for text horizontal alignment.
	TextHorizontalAlignUnset TextHorizontalAlign = 0
	// TextHorizontalAlignLeft aligns a string horizontally so that it's left ligature starts at horizontal pixel 0.
	TextHorizontalAlignLeft TextHorizontalAlign = 1
	// TextHorizontalAlignCenter left aligns a string horizontally so that there are equal pixels
	// to the left and to the right of a string within a box.
	TextHorizontalAlignCenter TextHorizontalAlign = 2
	// TextHorizontalAlignRight right aligns a string horizontally so that the right ligature ends at the right-most pixel
	// of a box.
	TextHorizontalAlignRight TextHorizontalAlign = 3
)

type TextStyle 

type TextStyle struct {
	HorizontalAlign TextHorizontalAlign
	VerticalAlign   TextVerticalAlign
	Wrap            TextWrap
}

TextStyle encapsulates text style options.

type TextVerticalAlign 

type TextVerticalAlign int

TextVerticalAlign is an enum for the vertical alignment options. 

const (
	// TextVerticalAlignUnset is the unset state for vertical alignment options.
	TextVerticalAlignUnset TextVerticalAlign = 0
	// TextVerticalAlignBaseline aligns text according to the "baseline" of the string, or where a normal ascender begins.
	TextVerticalAlignBaseline TextVerticalAlign = 1
	// TextVerticalAlignBottom aligns the text according to the lowers pixel of any of the ligatures (ex. g or q both extend below the baseline).
	TextVerticalAlignBottom TextVerticalAlign = 2
	// TextVerticalAlignMiddle aligns the text so that there is an equal amount of space above and below the top and bottom of the ligatures.
	TextVerticalAlignMiddle TextVerticalAlign = 3
	// TextVerticalAlignMiddleBaseline aligns the text veritcally so that there is an equal number of pixels above and below the baseline of the string.
	TextVerticalAlignMiddleBaseline TextVerticalAlign = 4
	// TextVerticalAlignTop alignts the text so that the top of the ligatures are at y-pixel 0 in the container.
	TextVerticalAlignTop TextVerticalAlign = 5
)

type TextWrap 

type TextWrap int

TextWrap is an enum for the word wrap options. 

const (
	// TextWrapUnset is the unset state for text wrap options.
	TextWrapUnset TextWrap = 0
	// TextWrapNone will spill text past horizontal boundaries.
	TextWrapNone TextWrap = 1
	// TextWrapWord will split a string on words (i.e. spaces) to fit within a horizontal boundary.
	TextWrapWord TextWrap = 2
	// TextWrapRune will split a string on a rune (i.e. utf-8 codepage) to fit within a horizontal boundary.
	TextWrapRune TextWrap = 3
)

type Tick 

type Tick struct {
	Value float64
	Label string
}

Tick represents a label on an axis.

func GenerateContinuousTicks 

func GenerateContinuousTicks(r Renderer, ra Range, isVertical bool, style Style, vf ValueFormatter) []Tick

GenerateContinuousTicks generates a set of ticks.

type TickPosition 

type TickPosition int

TickPosition is an enumeration of possible tick drawing positions. 

const (
	// TickPositionUnset means to use the default tick position.
	TickPositionUnset TickPosition = 0
	// TickPositionBetweenTicks draws the labels for a tick between the previous and current tick.
	TickPositionBetweenTicks TickPosition = 1
	// TickPositionUnderTick draws the tick below the tick.
	TickPositionUnderTick TickPosition = 2
)

type Ticks 

type Ticks []Tick

Ticks is an array of ticks.

func (Ticks) Len 

func (t Ticks) Len() int

Len returns the length of the ticks set.

func (Ticks) Less 

func (t Ticks) Less(i, j int) bool

Less returns if i's value is less than j's value.

func (Ticks) Swap 

func (t Ticks) Swap(i, j int)

Swap swaps two elements.

type TicksProvider 

type TicksProvider interface {
	GetTicks(r Renderer, defaults Style, vf ValueFormatter) []Tick
}

TicksProvider is a type that provides ticks.

type TimeSeries 

type TimeSeries struct {
	Name  string
	Style Style

	YAxis YAxisType

	XValues []time.Time
	YValues []float64
}

TimeSeries is a line on a chart.

func (TimeSeries) GetLastValue 

func (ts TimeSeries) GetLastValue() (x, y float64)

GetLastValue gets the last value.

func (TimeSeries) GetName 

func (ts TimeSeries) GetName() string

GetName returns the name of the time series.

func (TimeSeries) GetStyle 

func (ts TimeSeries) GetStyle() Style

GetStyle returns the line style.

func (TimeSeries) GetValue 

func (ts TimeSeries) GetValue(index int) (x, y float64)

GetValue gets a value at a given index.

func (TimeSeries) GetValueFormatters 

func (ts TimeSeries) GetValueFormatters() (x, y ValueFormatter)

GetValueFormatters returns value formatter defaults for the series.

func (TimeSeries) GetYAxis 

func (ts TimeSeries) GetYAxis() YAxisType

GetYAxis returns which YAxis the series draws on.

func (TimeSeries) Len 

func (ts TimeSeries) Len() int

Len returns the number of elements in the series.

func (TimeSeries) Render 

func (ts TimeSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style)

Render renders the series.

type Value 

type Value struct {
	Style Style
	Label string
	Value float64
}

Value is a chart value.

type Value2 

type Value2 struct {
	Style          Style
	Label          string
	XValue, YValue float64
}

Value2 is a two axis value.

type ValueFormatter 

type ValueFormatter func(v interface{}) string

ValueFormatter is a function that takes a value and produces a string.

type ValueFormatterProvider 

type ValueFormatterProvider interface {
	GetValueFormatters() (x, y ValueFormatter)
}

ValueFormatterProvider is a series that has custom formatters.

type ValueProvider 

type ValueProvider interface {
	Len() int
	GetValue(index int) (float64, float64)
}

ValueProvider is a type that produces values.

type Values 

type Values []Value

Values is an array of Value.

func (Values) Normalize 

func (vs Values) Normalize() []Value

Normalize returns the values normalized.

func (Values) Values 

func (vs Values) Values() []float64

Values returns the values.

func (Values) ValuesNormalized 

func (vs Values) ValuesNormalized() []float64

ValuesNormalized returns normalized values.

type XAxis 

type XAxis struct {
	Name           string
	NameStyle      Style
	Style          Style
	ValueFormatter ValueFormatter
	Range          Range
	Ticks          []Tick

	TickPosition TickPosition

	GridLines      []GridLine
	GridMajorStyle Style
	GridMinorStyle Style
}

XAxis represents the horizontal axis.

func (XAxis) GetGridLines 

func (xa XAxis) GetGridLines(ticks []Tick) []GridLine

GetGridLines returns the gridlines for the axis.

func (XAxis) GetName 

func (xa XAxis) GetName() string

GetName returns the name.

func (XAxis) GetStyle 

func (xa XAxis) GetStyle() Style

GetStyle returns the style.

func (XAxis) GetTickPosition 

func (xa XAxis) GetTickPosition(defaults ...TickPosition) TickPosition

GetTickPosition returns the tick position option for the axis.

func (XAxis) GetTicks 

func (xa XAxis) GetTicks(r Renderer, ra Range, defaults Style, vf ValueFormatter) []Tick

GetTicks returns the ticks for a series. The coalesce priority is:

  • User Supplied Ticks (i.e. Ticks array on the axis itself).
  • Range ticks (i.e. if the range provides ticks).
  • Generating continuous ticks based on minimum spacing and canvas width.

func (XAxis) Measure 

func (xa XAxis) Measure(r Renderer, canvasBox Box, ra Range, defaults Style, ticks []Tick) Box

Measure returns the bounds of the axis.

func (XAxis) Render 

func (xa XAxis) Render(r Renderer, canvasBox Box, ra Range, defaults Style, ticks []Tick)

Render renders the axis

type YAxis 

type YAxis struct {
	Name      string
	NameStyle Style

	Style Style

	Zero GridLine

	AxisType YAxisType

	ValueFormatter ValueFormatter
	Range          Range

	Ticks     []Tick
	GridLines []GridLine

	GridMajorStyle Style
	GridMinorStyle Style
}

YAxis is a veritcal rule of the range. There can be (2) y-axes; a primary and secondary.

func (YAxis) GetGridLines 

func (ya YAxis) GetGridLines(ticks []Tick) []GridLine

GetGridLines returns the gridlines for the axis.

func (YAxis) GetName 

func (ya YAxis) GetName() string

GetName returns the name.

func (YAxis) GetNameStyle 

func (ya YAxis) GetNameStyle() Style

GetNameStyle returns the name style.

func (YAxis) GetStyle 

func (ya YAxis) GetStyle() Style

GetStyle returns the style.

func (YAxis) GetTicks 

func (ya YAxis) GetTicks(r Renderer, ra Range, defaults Style, vf ValueFormatter) []Tick

GetTicks returns the ticks for a series. The coalesce priority is:

  • User Supplied Ticks (i.e. Ticks array on the axis itself).
  • Range ticks (i.e. if the range provides ticks).
  • Generating continuous ticks based on minimum spacing and canvas width.

func (YAxis) Measure 

func (ya YAxis) Measure(r Renderer, canvasBox Box, ra Range, defaults Style, ticks []Tick) Box

Measure returns the bounds of the axis.

func (YAxis) Render 

func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, defaults Style, ticks []Tick)

Render renders the axis.

type YAxisType 

type YAxisType int

YAxisType is a type of y-axis; it can either be primary or secondary. 

const (
	// YAxisPrimary is the primary axis.
	YAxisPrimary YAxisType = 0
	// YAxisSecondary is the secondary axis.
	YAxisSecondary YAxisType = 1
)

Source Files

View all Source files

Directories

Path Synopsis
_examples
annotations
axes
bar_chart
basic
custom_formatters
custom_padding
custom_ranges
custom_styles
custom_ticks
legend
linear_regression
market_hours
min_max
pie_chart
request_timings
simple_moving_average
stacked_bar
stock_analysis
timeseries
twoaxis

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