chart

package module
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 Go to latest Published: Oct 27, 2016 License: MIT Imports: 18 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 (
	// File contains file utility functions
	File = fileUtil{}
)
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{}
)
View Source 
var (
	// Time contains time utility functions.
	Time = timeUtil{}
)

Functions ¶

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 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) Corners ¶ 

func (b Box) Corners() BoxCorners

Corners returns the box as a set of corners.

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 BoxCorners ¶ 

type BoxCorners struct {
	TopLeft, TopRight, BottomRight, BottomLeft Point
}

BoxCorners is a box with independent corners.

func (BoxCorners) Box ¶ 

func (bc BoxCorners) Box() Box

Box return the BoxCorners as a regular box.

func (BoxCorners) Center ¶ 

func (bc BoxCorners) Center() (x, y int)

Center returns the center of the box

func (BoxCorners) Equals ¶ 

func (bc BoxCorners) Equals(other BoxCorners) bool

Equals returns if the box equals another box.

func (BoxCorners) Height ¶ 

func (bc BoxCorners) Height() int

Height returns the height

func (BoxCorners) Rotate ¶ 

func (bc BoxCorners) Rotate(thetaDegrees float64) BoxCorners

Rotate rotates the box.

func (BoxCorners) String ¶ 

func (bc BoxCorners) String() string

func (BoxCorners) Width ¶ 

func (bc BoxCorners) 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 ImageWriter ¶ 

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

ImageWriter is a special type of io.Writer that produces a final image.

func (*ImageWriter) Image ¶ 

func (ir *ImageWriter) Image() (image.Image, error)

Image returns an *image.Image for the result.

func (*ImageWriter) SetRGBA ¶ 

func (ir *ImageWriter) SetRGBA(i *image.RGBA)

SetRGBA sets a raw version of the image.

func (*ImageWriter) Write ¶ 

func (ir *ImageWriter) Write(buffer []byte) (int, error)

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 Point ¶ 

type Point struct {
	X, Y int
}

Point is an X,Y pair

func (Point) DistanceTo ¶ 

func (p Point) DistanceTo(other Point) float64

DistanceTo calculates the distance to another point.

func (Point) Equals ¶ 

func (p Point) Equals(other Point) bool

Equals returns if a point equals another point.

func (Point) String ¶ 

func (p Point) String() string

String returns a string representation of the point.

type RGBACollector ¶ 

type RGBACollector interface {
	SetRGBA(i *image.RGBA)
}

RGBACollector is a render target for a chart.

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.

func LegendThin ¶ 

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

LegendThin is a legend that doesn't obscure the chart area.

type Renderer ¶ 

type Renderer interface {
	// ResetStyle should reset any style related settings on the renderer.
	ResetStyle()

	// 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
	TextRotationDegrees float64 //0 is unset or normal
}

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) GetTextRotationDegrees ¶ 

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

GetTextRotationDegrees returns the text rotation in degrees.

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

	TickStyle    Style
	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

	TickStyle Style
	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) GetTickStyle ¶ 

func (ya YAxis) GetTickStyle() Style

GetTickStyle returns the tick 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 command
axes command
axes_labels command
bar_chart command
basic command
custom_formatters command
custom_padding command
custom_ranges command
custom_styles command
custom_ticks command
image_writer command
legend command
linear_regression command
market_hours command
min_max command
pie_chart command
request_timings command
simple_moving_average command
stacked_bar command
stock_analysis command
text_rotation command
timeseries command
twoaxis command

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