svgxml

package module
v0.0.8 Latest Latest
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 Go to latest Published: Aug 20, 2026 License: MIT Imports: 10 Imported by: 0

README

svgxml

This has grown out of my need for a way in Go to manage the structures of SVG images in a way that's more straightforward than working with encoding/xml directly and repeating code across projects. It's incredibly incomplete relative to the SVG spec but works OK for what's implemented.

As this is intended for managing the structure of an image, the focus is on finding, examining, and modifying existing elements. Adding elements can also be done easily if not simply; array management (for element ordering) and generating and setting the values of the XML attributes is left to the user. For the most part, no major abstractions are provided for creating or modifying elements.

What little documentation I have is mainly what's been generated from my code comments; see pkg.go.dev.

Documentation

Index

Constants

View Source 
const (
	FindFirst = true
	FindAll   = false
)

Variables

This section is empty.

Functions

This section is empty.

Types

type AnchorDef 

type AnchorDef struct {
	Id             string      `xml:"id,attr"`
	Download       string      `xml:"Download,attr"`
	Href           string      `xml:"href,attr"`
	HrefLang       string      `xml:"hreflang,attr"`
	ReferrerPolicy string      `xml:"referrerpolicy,attr"`
	Rel            string      `xml:"rel,attr"`
	Target         string      `xml:"target,attr"`
	Type           string      `xml:"type,attr"`
	Xform          string      `xml:"transform,attr,omitempty"`
	G              []GroupDef  `xml:"g"`
	Rect           []RectDef   `xml:"rect"`
	Circle         []CircleDef `xml:"circle"`
}

<a> SVG/XML element

type CircleDef 

type CircleDef struct {
	Id     string `xml:"id,attr"`
	CX     string `xml:"cx,attr"`
	CY     string `xml:"cy,attr"`
	Radius string `xml:"r,attr"`
	Style  string `xml:"style,attr,omitempty"`
	Xform  string `xml:"transform,attr,omitempty"`
}

<circle> SVG/XML element

type DefsDef 

type DefsDef struct {
	Id string `xml:"id,attr"`
}

<defs> SVG/XML element

type GroupDef 

type GroupDef struct {
	G      []GroupDef  `xml:"g,omitempty"`
	Id     string      `xml:"id,attr,omitempty"`
	Xform  string      `xml:"transform,attr,omitempty"`
	Style  string      `xml:"style,attr,omitempty"`
	A      []AnchorDef `xml:"a"`
	Path   []PathDef   `xml:"path"`
	Text   []TextDef   `xml:"text"`
	Rect   []RectDef   `xml:"rect"`
	Circle []CircleDef `xml:"circle"`
}

<g> SVG/XML element

func (*GroupDef) FindPathsById 

func (G *GroupDef) FindPathsById(id any, findFirst bool) ([]*PathDef, error)

FindGroupsById traverses a GroupDef object and returns a slice of PathDef with matching ids.

The supplied id may be a string or a compiled regular expression from the regexp package.

Use the FindFirst or FindAll constant as the second parameter to direct cause the method to return only the first matching element or all matching elements, respectively.

type NumberAttr added in v0.0.3 

type NumberAttr interface {
	int | int32 | int64 | float32 | float64 | string
}

Type constraint for functions

type PathDef 

type PathDef struct {
	Id    string `xml:"id,attr"`
	D     string `xml:"d,attr"`
	Xform string `xml:"transform,attr,omitempty"`
	Style string `xml:"style,attr,omitempty"`
	Title string `xml:"title,omitempty"`
}

<path> SVG/XML element

type RectDef 

type RectDef struct {
	Id     string `xml:"id,attr"`
	X      string `xml:"x,attr"`
	Y      string `xml:"y,attr"`
	Width  string `xml:"width,attr"`
	Height string `xml:"height,attr"`
	Style  string `xml:"style,attr,omitempty"`
	Xform  string `xml:"transform,attr,omitempty"`
}

<rect> SVG/XML element

func NewRect 

func NewRect[N NumberAttr](id, style string, x, y, width, height N) RectDef

NewRect returns a RectDef object with the supplied parameters. x, y, width, and height can be all strings or a mix of int or float types (but not a mix of strings and ints/floats).

type SVG 

type SVG struct {
	Id      string      `xml:"id,attr"`
	Width   string      `xml:"width,attr"`
	Height  string      `xml:"height,attr"`
	ViewBox string      `xml:"viewBox,attr,omitempty"`
	Title   string      `xml:"title,attr,omitempty"`
	Version string      `xml:"version,attr"`
	XMLNS   string      `xml:"xmlns,attr"`
	XMLName xml.Name    `xml:"svg"`
	Defs    DefsDef     `xml:"defs"`
	G       []GroupDef  `xml:"g"`
	A       []AnchorDef `xml:"a"`
	Path    []PathDef   `xml:"path"`
	Text    []TextDef   `xml:"text"`
	Rect    []RectDef   `xml:"rect"`
	Circle  []CircleDef `xml:"circle"`
	// contains filtered or unexported fields
}

SVG is the base struct of an SVG image, corresponding to the <svg>...</svg> tag pair and its attributes and contents. The array fields of the struct are the supported tags and will be rendered in first-to-last order (e. g., any circle defined in SVG.Circle will visually cover any other elements within its bounds).

func NewFromBytes 

func NewFromBytes(xmlBytes []byte) (*SVG, error)

NewFromBytes accepts a byte slice of SVG XML data and returns an SVG object pointer or an error.

func NewFromFile 

func NewFromFile(filename string) (*SVG, error)

NewFromFile accepts a filename containing SVG XML data and returns an object pointer or an error.

This method calls NewFromBytes after successfully reading from the file named in the filename parameter.

func (*SVG) AddBackground 

func (S *SVG) AddBackground(colorDef string) error

AddBackground takes a color definition, such as "#<hex>" or a name like "red", and creates a rect matching the image's viewBox or x/y/width/height and with the specified fill color.

func (*SVG) FindGroupsById 

func (S *SVG) FindGroupsById(id any, findFirst bool) ([]*GroupDef, error)

FindGroupsById traverses a GroupDef object and returns a slice of GroupDef with matching ids.

The supplied id may be a string or a compiled regular expression from the regexp package.

Use the FindFirst or FindAll constant as the second parameter to direct cause the method to return only the first matching element or all matching elements, respectively.

func (*SVG) FindPathsById 

func (S *SVG) FindPathsById(id any, findFirst bool) ([]*PathDef, error)

FindPathsById traverses an SVG object and returns a slice of PathDef with matching ids.

The supplied id may be a string or a compiled regular expression from the regexp package.

Use the FindFirst or FindAll constant as the second parameter to direct cause the method to return only the first matching element or all matching elements, respectively.

func (*SVG) GetBackground added in v0.0.7 

func (S *SVG) GetBackground() RectDef

GetBackground returns the RectDef created with SVG.AddBackground. If no background has been defined, the return value will be a RectDef with all zero values.

func (*SVG) GetViewBox 

func (S *SVG) GetViewBox() (ViewBoxDef, error)

GetViewBox returns the value of the "viewBox" XML attribute as a ViewBoxDef struct of float64 values.

func (*SVG) GetXml 

func (S *SVG) GetXml() ([]byte, error)

GetXml returns the current object as an XML byte slice. If a background has been defined with SVG.AddBackground, it is inserted into a copy of S as the bottom-most visual element, and the copy is marshaled to XML; otherwise S is marshaled as-is.

func (*SVG) GetXmlIndented 

func (S *SVG) GetXmlIndented(indentPrefix, indentString string) ([]byte, error)

GetXmlIndented returns the current object as an XML byte slice. If a background has been defined with SVG.AddBackground, it is inserted into a copy of S as the bottom-most visual element, and the copy is marshaled to XML; otherwise S is marshaled as-is.

The indentPrefix and indentString parameters are passed directly to xml.MarshalIndent.

func (*SVG) RemoveBackground added in v0.0.7 

func (S *SVG) RemoveBackground()

RemoveBackground clears any rect added by SVG.AddBackground

func (*SVG) SetViewBox 

func (S *SVG) SetViewBox(box ViewBoxDef)

GetViewBox sets the image's "viewBox" XML attribute from the values in the supplied ViewBoxDef struct.

func (*SVG) WriteFile 

func (S *SVG) WriteFile(filename string) error

WriteFile writes an XML representation of the current object to the supplied filename.

The method calls the SVG.GetXml method and writes the XML data to disk rather than returning a byte slice to the caller. The data is first written to a temporary file; if that succeeds, the file with the specified filename is unlinked and the temporary file renamed.

func (*SVG) WriteFileIndented added in v0.0.7 

func (S *SVG) WriteFileIndented(filename, indentPrefix, indentString string) error

WriteFileIndented writes an XML representation of the current object to the supplied filename.

The method calls the SVG.GetXmlIndented method and writes the XML data to disk rather than returning a byte slice to the caller. The data is first written to a temporary file; if that succeeds, the file with the specified filename is unlinked and the temporary file renamed.

type TSpanDef 

type TSpanDef struct {
	Id    string `xml:"id,attr"`
	X     string `xml:"x,attr"`
	Y     string `xml:"y,attr"`
	Xform string `xml:"transform,attr,omitempty"`
	Label string `xml:",chardata"`
}

<tspan> SVG/XML element

type TextDef 

type TextDef struct {
	Id         string     `xml:"id,attr"`
	X          string     `xml:"x,attr"`
	Y          string     `xml:"y,attr"`
	Style      string     `xml:"style,attr,omitempty"`
	Xform      string     `xml:"transform,attr,omitempty"`
	TextLength string     `xml:",attr,omitempty"`
	Label      string     `xml:",chardata"`
	TSpan      []TSpanDef `xml:"tspan"`
}

<text> SVG/XML element

type ViewBoxDef 

type ViewBoxDef struct {
	X      float64
	Y      float64
	Width  float64
	Height float64
}

"viewBox" attribute of some elements

Source Files

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