go-chart/chart.go

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package chart
import (
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"errors"
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"io"
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"math"
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"github.com/golang/freetype/truetype"
)
// Chart is what we're drawing.
type Chart struct {
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Title string
TitleStyle Style
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Width int
Height int
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DPI float64
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Background Style
Canvas Style
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XAxis XAxis
YAxis YAxis
YAxisSecondary YAxis
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Font *truetype.Font
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Series []Series
}
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// GetDPI returns the dpi for the chart.
func (c Chart) GetDPI(defaults ...float64) float64 {
if c.DPI == 0 {
if len(defaults) > 0 {
return defaults[0]
}
return DefaultDPI
}
return c.DPI
}
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// GetFont returns the text font.
func (c Chart) GetFont() (*truetype.Font, error) {
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if c.Font == nil {
f, err := GetDefaultFont()
if err != nil {
return nil, err
}
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return f, nil
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}
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return c.Font, nil
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}
// Render renders the chart with the given renderer to the given io.Writer.
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func (c Chart) Render(rp RendererProvider, w io.Writer) error {
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if len(c.Series) == 0 {
return errors.New("Please provide at least one series")
}
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c.YAxisSecondary.AxisType = YAxisSecondary
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r, err := rp(c.Width, c.Height)
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if err != nil {
return err
}
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font, err := c.GetFont()
if err != nil {
return err
}
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c.Font = font
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r.SetFont(font)
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r.SetDPI(c.GetDPI(DefaultDPI))
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c.drawBackground(r)
var xt, yt, yta []Tick
xr, yr, yra := c.getRanges()
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canvasBox := c.getDefaultCanvasBox()
xf, yf, yfa := c.getValueFormatters()
xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra)
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if c.hasAxes() {
xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa)
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canvasBox = c.getAxisAdjustedCanvasBox(r, canvasBox, xr, yr, yra, xt, yt, yta)
xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra)
xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa)
}
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if c.hasAnnotationSeries() {
canvasBox = c.getAnnotationAdjustedCanvasBox(r, canvasBox, xr, yr, yra, xf, yf, yfa)
xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra)
xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa)
}
c.drawCanvas(r, canvasBox)
c.drawAxes(r, canvasBox, xr, yr, yra, xt, yt, yta)
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for index, series := range c.Series {
c.drawSeries(r, canvasBox, xr, yr, yra, series, index)
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}
c.drawTitle(r)
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return r.Save(w)
}
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func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
var minx, maxx float64 = math.MaxFloat64, 0
var miny, maxy float64 = math.MaxFloat64, 0
var minya, maxya float64 = math.MaxFloat64, 0
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for _, s := range c.Series {
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seriesAxis := s.GetYAxis()
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if vp, isValueProvider := s.(ValueProvider); isValueProvider {
seriesLength := vp.Len()
for index := 0; index < seriesLength; index++ {
vx, vy := vp.GetValue(index)
minx = math.Min(minx, vx)
maxx = math.Max(maxx, vx)
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if seriesAxis == YAxisPrimary {
miny = math.Min(miny, vy)
maxy = math.Max(maxy, vy)
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} else if seriesAxis == YAxisSecondary {
minya = math.Min(minya, vy)
maxya = math.Max(maxya, vy)
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}
}
}
}
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if !c.XAxis.Range.IsZero() {
xrange.Min = c.XAxis.Range.Min
xrange.Max = c.XAxis.Range.Max
} else {
xrange.Min = minx
xrange.Max = maxx
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}
if !c.YAxis.Range.IsZero() {
yrange.Min = c.YAxis.Range.Min
yrange.Max = c.YAxis.Range.Max
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} else {
yrange.Min = miny
yrange.Max = maxy
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yrange.Min, yrange.Max = yrange.GetRoundedRangeBounds()
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}
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if !c.YAxisSecondary.Range.IsZero() {
yrangeAlt.Min = c.YAxisSecondary.Range.Min
yrangeAlt.Max = c.YAxisSecondary.Range.Max
} else {
yrangeAlt.Min = minya
yrangeAlt.Max = maxya
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yrangeAlt.Min, yrangeAlt.Max = yrangeAlt.GetRoundedRangeBounds()
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}
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return
}
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func (c Chart) getDefaultCanvasBox() Box {
dpt := c.Background.Padding.GetTop(DefaultBackgroundPadding.Top)
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dpl := c.Background.Padding.GetLeft(DefaultBackgroundPadding.Left)
dpr := c.Background.Padding.GetRight(DefaultBackgroundPadding.Right)
dpb := c.Background.Padding.GetBottom(DefaultBackgroundPadding.Bottom)
return Box{
Top: dpt,
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Left: dpl,
Right: c.Width - dpr,
Bottom: c.Height - dpb,
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}
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}
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func (c Chart) getValueFormatters() (x, y, ya ValueFormatter) {
for _, s := range c.Series {
if vfp, isVfp := s.(ValueFormatterProvider); isVfp {
sx, sy := vfp.GetValueFormatters()
if s.GetYAxis() == YAxisPrimary {
x = sx
y = sy
} else if s.GetYAxis() == YAxisSecondary {
x = sx
ya = sy
}
}
}
if c.XAxis.ValueFormatter != nil {
x = c.XAxis.ValueFormatter
}
if c.YAxis.ValueFormatter != nil {
y = c.YAxis.ValueFormatter
}
if c.YAxisSecondary.ValueFormatter != nil {
ya = c.YAxisSecondary.ValueFormatter
}
return
}
func (c Chart) hasAxes() bool {
return c.XAxis.Style.Show || c.YAxis.Style.Show || c.YAxisSecondary.Style.Show
}
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func (c Chart) getAxesTicks(r Renderer, xr, yr, yar Range, xf, yf, yfa ValueFormatter) (xticks, yticks, yticksAlt []Tick) {
if c.XAxis.Style.Show {
xticks = c.XAxis.GetTicks(r, xr, xf)
}
if c.YAxis.Style.Show {
yticks = c.YAxis.GetTicks(r, yr, yf)
}
if c.YAxisSecondary.Style.Show {
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yticksAlt = c.YAxisSecondary.GetTicks(r, yar, yf)
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}
return
}
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func (c Chart) getAxisAdjustedCanvasBox(r Renderer, canvasBox Box, xr, yr, yra Range, xticks, yticks, yticksAlt []Tick) Box {
axesOuterBox := canvasBox.Clone()
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if c.XAxis.Style.Show {
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axesBounds := c.XAxis.Measure(r, canvasBox, xr, xticks)
axesOuterBox = axesOuterBox.Grow(axesBounds)
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}
if c.YAxis.Style.Show {
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axesBounds := c.YAxis.Measure(r, canvasBox, yr, yticks)
axesOuterBox = axesOuterBox.Grow(axesBounds)
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}
if c.YAxisSecondary.Style.Show {
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axesBounds := c.YAxisSecondary.Measure(r, canvasBox, yra, yticksAlt)
axesOuterBox = axesOuterBox.Grow(axesBounds)
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}
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return canvasBox.OuterConstrain(c.asBox(), axesOuterBox)
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}
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func (c Chart) setRangeDomains(canvasBox Box, xr, yr, yra Range) (xr2, yr2, yra2 Range) {
xr2.Min, xr2.Max = xr.Min, xr.Max
xr2.Domain = canvasBox.Width()
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yr2.Min, yr2.Max = yr.Min, yr.Max
yr2.Domain = canvasBox.Height()
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yra2.Min, yra2.Max = yra.Min, yra.Max
yra2.Domain = canvasBox.Height()
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return
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}
func (c Chart) hasAnnotationSeries() bool {
for _, s := range c.Series {
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if as, isAnnotationSeries := s.(AnnotationSeries); isAnnotationSeries {
if as.Style.Show {
return true
}
}
}
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return false
}
func (c Chart) getAnnotationAdjustedCanvasBox(r Renderer, canvasBox Box, xr, yr, yra Range, xf, yf, yfa ValueFormatter) Box {
annotationSeriesBox := canvasBox.Clone()
for seriesIndex, s := range c.Series {
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if as, isAnnotationSeries := s.(AnnotationSeries); isAnnotationSeries {
if as.Style.Show {
style := c.seriesStyleDefaults(seriesIndex)
var annotationBounds Box
if as.YAxis == YAxisPrimary {
annotationBounds = as.Measure(r, canvasBox, xr, yr, style)
} else if as.YAxis == YAxisSecondary {
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annotationBounds = as.Measure(r, canvasBox, xr, yra, style)
}
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annotationSeriesBox = annotationSeriesBox.Grow(annotationBounds)
}
}
}
return canvasBox.OuterConstrain(c.asBox(), annotationSeriesBox)
}
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func (c Chart) drawBackground(r Renderer) {
DrawBox(r, Box{Right: c.Width, Bottom: c.Height}, c.Canvas.WithDefaultsFrom(Style{
FillColor: DefaultBackgroundColor,
StrokeColor: DefaultBackgroundStrokeColor,
StrokeWidth: DefaultStrokeWidth,
}))
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}
func (c Chart) drawCanvas(r Renderer, canvasBox Box) {
DrawBox(r, canvasBox, c.Canvas.WithDefaultsFrom(Style{
FillColor: DefaultCanvasColor,
StrokeColor: DefaultCanvasStrokeColor,
StrokeWidth: DefaultStrokeWidth,
}))
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}
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func (c Chart) drawAxes(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt Range, xticks, yticks, yticksAlt []Tick) {
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if c.XAxis.Style.Show {
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c.XAxis.Render(r, canvasBox, xrange, xticks)
}
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if c.YAxis.Style.Show {
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c.YAxis.Render(r, canvasBox, yrange, yticks)
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}
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if c.YAxisSecondary.Style.Show {
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c.YAxisSecondary.Render(r, canvasBox, yrangeAlt, yticksAlt)
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}
}
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func (c Chart) drawSeries(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt Range, s Series, seriesIndex int) {
if s.GetYAxis() == YAxisPrimary {
s.Render(r, canvasBox, xrange, yrange, c.seriesStyleDefaults(seriesIndex))
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} else if s.GetYAxis() == YAxisSecondary {
s.Render(r, canvasBox, xrange, yrangeAlt, c.seriesStyleDefaults(seriesIndex))
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}
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}
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func (c Chart) drawTitle(r Renderer) {
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if len(c.Title) > 0 && c.TitleStyle.Show {
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r.SetFont(c.TitleStyle.GetFont(c.Font))
r.SetFontColor(c.TitleStyle.GetFontColor(DefaultTextColor))
titleFontSize := c.TitleStyle.GetFontSize(DefaultTitleFontSize)
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r.SetFontSize(titleFontSize)
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textBox := r.MeasureText(c.Title)
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textWidth := textBox.Width()
textHeight := textBox.Height()
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titleX := (c.Width >> 1) - (textWidth >> 1)
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titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + textHeight
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r.Text(c.Title, titleX, titleY)
}
}
func (c Chart) seriesStyleDefaults(seriesIndex int) Style {
strokeColor := GetDefaultSeriesStrokeColor(seriesIndex)
return Style{
StrokeColor: strokeColor,
StrokeWidth: DefaultStrokeWidth,
Font: c.Font,
FontSize: DefaultFontSize,
}
}
func (c Chart) asBox() Box {
return Box{Right: c.Width, Bottom: c.Height}
}