go-chart/style.go

package chart

import (
	"fmt"
	"strings"

	"github.com/wcharczuk/go-chart/drawing"
)

// Style is a simple style set.
type Style struct {
	Show        bool
	StrokeColor drawing.Color
	FillColor   drawing.Color
	StrokeWidth float64
	FontSize    float64
	FontColor   drawing.Color
	Padding     Box
}

// IsZero returns if the object is set or not.
func (s Style) IsZero() bool {
	return s.StrokeColor.IsZero() && s.FillColor.IsZero() && s.StrokeWidth == 0 && s.FontSize == 0
}

// GetStrokeColor returns the stroke color.
func (s Style) GetStrokeColor(defaults ...drawing.Color) drawing.Color {
	if s.StrokeColor.IsZero() {
		if len(defaults) > 0 {
			return defaults[0]
		}
		return drawing.ColorTransparent
	}
	return s.StrokeColor
}

// GetFillColor returns the fill color.
func (s Style) GetFillColor(defaults ...drawing.Color) drawing.Color {
	if s.FillColor.IsZero() {
		if len(defaults) > 0 {
			return defaults[0]
		}
		return drawing.ColorTransparent
	}
	return s.FillColor
}

// GetStrokeWidth returns the stroke width.
func (s Style) GetStrokeWidth(defaults ...float64) float64 {
	if s.StrokeWidth == 0 {
		if len(defaults) > 0 {
			return defaults[0]
		}
		return DefaultStrokeWidth
	}
	return s.StrokeWidth
}

// GetFontSize gets the font size.
func (s Style) GetFontSize(defaults ...float64) float64 {
	if s.FontSize == 0 {
		if len(defaults) > 0 {
			return defaults[0]
		}
		return DefaultFontSize
	}
	return s.FontSize
}

// GetFontColor gets the font size.
func (s Style) GetFontColor(defaults ...drawing.Color) drawing.Color {
	if s.FontColor.IsZero() {
		if len(defaults) > 0 {
			return defaults[0]
		}
		return drawing.ColorTransparent
	}
	return s.FontColor
}

// SVG returns the style as a svg style string.
func (s Style) SVG(dpi float64) string {
	sw := s.StrokeWidth
	sc := s.StrokeColor
	fc := s.FillColor
	fs := s.FontSize
	fnc := s.FontColor

	strokeWidthText := "stroke-width:0"
	if sw != 0 {
		strokeWidthText = "stroke-width:" + fmt.Sprintf("%d", int(sw))
	}

	strokeText := "stroke:none"
	if !sc.IsZero() {
		strokeText = "stroke:" + sc.String()
	}

	fillText := "fill:none"
	if !fc.IsZero() {
		fillText = "fill:" + fc.String()
	}

	fontSizeText := ""
	if fs != 0 {
		fontSizeText = "font-size:" + fmt.Sprintf("%.1fpx", drawing.PointsToPixels(dpi, fs))
	}

	if !fnc.IsZero() {
		fillText = "fill:" + fnc.String()
	}
	return strings.Join([]string{strokeWidthText, strokeText, fillText, fontSizeText}, ";")
}