73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
package chart
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// GridLineProvider is a type that provides grid lines.
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type GridLineProvider interface {
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GetGridLines(ticks []Tick, isVertical bool, majorStyle, minorStyle Style) []GridLine
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}
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// GridLine is a line on a graph canvas.
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type GridLine struct {
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IsMinor bool
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Style Style
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Value float64
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}
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// Major returns if the gridline is a `major` line.
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func (gl GridLine) Major() bool {
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return !gl.IsMinor
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}
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// Minor returns if the gridline is a `minor` line.
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func (gl GridLine) Minor() bool {
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return gl.IsMinor
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}
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// Render renders the gridline
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func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range, isVertical bool, defaults Style) {
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r.SetStrokeColor(gl.Style.GetStrokeColor(defaults.GetStrokeColor()))
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r.SetStrokeWidth(gl.Style.GetStrokeWidth(defaults.GetStrokeWidth()))
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r.SetStrokeDashArray(gl.Style.GetStrokeDashArray(defaults.GetStrokeDashArray()))
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if isVertical {
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lineLeft := canvasBox.Left + ra.Translate(gl.Value)
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lineBottom := canvasBox.Bottom
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lineTop := canvasBox.Top
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r.MoveTo(lineLeft, lineBottom)
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r.LineTo(lineLeft, lineTop)
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r.Stroke()
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} else {
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lineLeft := canvasBox.Left
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lineRight := canvasBox.Right
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lineHeight := canvasBox.Bottom - ra.Translate(gl.Value)
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r.MoveTo(lineLeft, lineHeight)
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r.LineTo(lineRight, lineHeight)
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r.Stroke()
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}
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}
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// GenerateGridLines generates grid lines.
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func GenerateGridLines(ticks []Tick, majorStyle, minorStyle Style) []GridLine {
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var gl []GridLine
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isMinor := false
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if len(ticks) < 3 {
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return gl
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}
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for _, t := range ticks[1 : len(ticks)-1] {
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s := majorStyle
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if isMinor {
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s = minorStyle
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}
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gl = append(gl, GridLine{
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Style: s,
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IsMinor: isMinor,
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Value: t.Value,
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})
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isMinor = !isMinor
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}
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return gl
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}
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