Ttykuu

I'm attempting to parse an SVG file to get all of the colors that are present in the file. SVGs are XML based and their structure can vary a bit. For example:

<svg viewBox="-80 -80 160 160">
 <g stroke="black" fill="none">
 <path d='...' fill='#0FF'/>
 <path d='...' fill='#F0F'/>
 ...
 </g>
</svg>

and

<svg viewBox="0 0 100 100">
 <a>
 <path d="..." stroke="black" fill="red"/>
 <ellipse stroke="black" fill="white" cx="50" cy="40" rx="22" ry="35"/>
 <circle cx="50" cy="40" r="5" stroke="black" fill="red"/>
 </a>
</svg>

and

<svg viewBox="0 0 80 120">
 <rect id="background-rect" x="0%" y="0%" width="100%" height="100%" fill="#aaaaaa"/>
</svg>

Are all examples of valid SVGs. At first I attempted to create the underlying structs that would allow me to represent all of these structures but then I decided to take a more generic approach that would focus soley on the fill attribute which is all I care about:

type GenericNode struct 
 XMLName xml.Name
 Fill string `xml:"fill,attr"`
 Nodes []GenericNode `xml:",any"`


func (s *SVGController) GetColorsFromXML() []string 
 xmlFile, _ := os.Open(s.Path)
 byteValue, _ := ioutil.ReadAll(xmlFile)
 var svg GenericNode
 xml.Unmarshal(byteValue, &svg)

 // Using a map here to avoid having to worry about having
 // duplicate colors in the color slice
 colorMap := make(map[string]struct)
 colorMap = getSVGColors(svg, colorMap)

 // Once we have a complete color map extract all the keys
 // to an array and return it.
 colors := make([]string, len(colorMap))
 i := 0
 for k := range colorMap 
 colors[i] = k
 i++
 
 return colors


func getSVGColors(svg GenericNode, colors map[string]struct) map[string]struct 
 if svg.Fill != "" && strings.ToLower(svg.Fill) != "none" 
 colors[svg.Fill] = struct
 
 for _, node := range svg.Nodes 
 colors = getSVGColors(node, colors)
 
 return colors

Is this a reasonable approach to take? Am I doing anything here that should be avoided?