oksvg

package module
v0.0.5 Latest Latest
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 Go to latest Published: Apr 10, 2022 License: BSD-3-Clause Imports: 28 Imported by: 4

README

oksvg

oksvg is a rasterizer for a partial implementation of the SVG2.0 specification in golang.

Although many SVG elements will not be read by oksvg, it is good enough to faithfully produce thousands, but certainly not all, SVG icons available both for free and commercially. A list of valid and invalid elements is in the doc folder.

oksvg uses the rasterx rasterizer package which implements full SVG2.0 path functions, including the newer 'arc' join-mode.

arcs and caps

Extra non-standard features.

In addition to 'arc' as a valid join mode value, oksvg also allows 'arc-clip' which is the arc analog of miter-clip and some extra capping and gap values. It can also specify different capping functions for line starts and ends.

Rasterizations of SVG to PNG from creative commons 3.0 sources.

Example renderings of unedited open source SVG files by oksvg and rasterx are shown below.

Thanks to Freepik from Flaticon Licensed by Creative Commons 3.0 for the example icons shown below, and also used as test icons in the testdata folder.

Jupiter

lander

mountains

bus

Non-standard library dependencies

oksvg requires the following imports which are not included in the go standard library:

  • golang.org/x/net/html/charset
  • golang.org/x/image/colornames
  • golang.org/x/image/math/fixed

These can be included in your gopath by the following 'get' commands:

  • "go get golang.org/x/image/math/fixed"
  • "go get golang.org/x/image/colornames"
  • "go get golang.org/x/net/html/charset"

oksvg also requires the user to get or clone into the workspace the rasterx package located here:

  • github.com/srwiley/rasterx

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var DefaultStyle = PathStyle{1.0, 1.0, 2.0, 0.0, 4.0, nil, true,
	color.NRGBA{0x00, 0x00, 0x00, 0xff}, nil,
	nil, nil, rasterx.ButtCap, rasterx.Bevel, rasterx.MatrixAdder{M: rasterx.Identity}}

DefaultStyle sets the default PathStyle to fill black, winding rule, full opacity, no stroke, ButtCap line end and Bevel line connect.

Functions

func ParseSVGColor 

func ParseSVGColor(colorStr string) (color.Color, error)

ParseSVGColor parses an SVG color string in all forms including all SVG1.1 names, obtained from the image.colornames package

func ParseSVGColorNum 

func ParseSVGColorNum(colorStr string) (r, g, b uint8, err error)

ParseSVGColorNum reads the SFG color string e.g. #FBD9BD

Types

type ErrorMode 

type ErrorMode uint8

ErrorMode is the for setting how the parser reacts to unparsed elements 

const (
	// IgnoreErrorMode skips un-parsed SVG elements.
	IgnoreErrorMode ErrorMode = iota

	// WarnErrorMode outputs a warning when an un-parsed SVG element is found.
	WarnErrorMode

	// StrictErrorMode causes an error when an un-parsed SVG element is found.
	StrictErrorMode
)

type IconCursor 

type IconCursor struct {
	PathCursor

	StyleStack []PathStyle
	// contains filtered or unexported fields
}

IconCursor is used while parsing SVG files.

func (*IconCursor) PushStyle 

func (c *IconCursor) PushStyle(attrs []xml.Attr) error

PushStyle parses the style element, and push it on the style stack. Only color and opacity are supported for fill. Note that this parses both the contents of a style attribute plus direct fill and opacity attributes.

func (*IconCursor) ReadGradAttr 

func (c *IconCursor) ReadGradAttr(attr xml.Attr) (err error)

ReadGradAttr reads an SVG gradient attribute

func (*IconCursor) ReadGradURL 

func (c *IconCursor) ReadGradURL(v string, defaultColor interface{}) (grad rasterx.Gradient, ok bool)

ReadGradURL reads an SVG format gradient url Since the context of the gradient can affect the colors the current fill or line color is passed in and used in the case of a nil stopClor value

type PathCursor 

type PathCursor struct {
	rasterx.Path

	ErrorMode ErrorMode
	// contains filtered or unexported fields
}

PathCursor is used to parse SVG format path strings into a rasterx Path

func (*PathCursor) AddArcFromA 

func (c *PathCursor) AddArcFromA(points []float64)

AddArcFromA adds a path of an arc element to the cursor path to the PathCursor

func (*PathCursor) CompilePath 

func (c *PathCursor) CompilePath(svgPath string) error

CompilePath translates the svgPath description string into a rasterx path. All valid SVG path elements are interpreted to rasterx equivalents. The resulting path element is stored in the PathCursor.

func (*PathCursor) EllipseAt 

func (c *PathCursor) EllipseAt(cx, cy, rx, ry float64)

EllipseAt adds a path of an elipse centered at cx, cy of radius rx and ry to the PathCursor

func (*PathCursor) GetPoints 

func (c *PathCursor) GetPoints(dataPoints string) error

GetPoints reads a set of floating point values from the SVG format number string, and add them to the cursor's points slice.

func (*PathCursor) ReadFloat 

func (c *PathCursor) ReadFloat(numStr string) error

ReadFloat reads a floating point value and adds it to the cursor's points slice.

type PathStyle 

type PathStyle struct {
	FillOpacity, LineOpacity          float64
	LineWidth, DashOffset, MiterLimit float64
	Dash                              []float64
	UseNonZeroWinding                 bool

	LineGap     rasterx.GapFunc
	LeadLineCap rasterx.CapFunc // This is used if different than LineCap
	LineCap     rasterx.CapFunc
	LineJoin    rasterx.JoinMode
	// contains filtered or unexported fields
}

PathStyle holds the state of the SVG style.

type SvgIcon 

type SvgIcon struct {
	ViewBox      struct{ X, Y, W, H float64 }
	Titles       []string // Title elements collect here
	Descriptions []string // Description elements collect here
	Grads        map[string]*rasterx.Gradient
	Defs         map[string][]definition
	SVGPaths     []SvgPath
	SvgTexts     []SvgText
	Transform    rasterx.Matrix2D
	// contains filtered or unexported fields
}

SvgIcon holds data from parsed SVGs.

func ReadIcon 

func ReadIcon(iconFile string, errMode ...ErrorMode) (*SvgIcon, error)

ReadIcon reads the Icon from the named file. This only supports a sub-set of SVG, but is enough to draw many icons. If errMode is provided, the first value determines if the icon ignores, errors out, or logs a warning if it does not handle an element found in the icon file. Ignore warnings is the default if no ErrorMode value is provided.

func ReadIconStream 

func ReadIconStream(stream io.Reader, errMode ...ErrorMode) (*SvgIcon, error)

ReadIconStream reads the Icon from the given io.Reader. This only supports a sub-set of SVG, but is enough to draw many icons. If errMode is provided, the first value determines if the icon ignores, errors out, or logs a warning if it does not handle an element found in the icon file. Ignore warnings is the default if no ErrorMode value is provided.

func ReadReplacingCurrentColor added in v0.0.3 

func ReadReplacingCurrentColor(stream io.Reader, currentColor string, errMode ...ErrorMode) (icon *SvgIcon, err error)

ReadReplacingCurrentColor replaces currentColor value with specified value and loads SvgIcon as ReadIconStream do. currentColor value should be valid hex, rgb or named color value.

func (*SvgIcon) Draw 

func (s *SvgIcon) Draw(r *rasterx.Dasher, opacity float64)

Draw the compiled SVG icon into the GraphicContext. All elements should be contained by the Bounds rectangle of the SvgIcon.

func (*SvgIcon) DrawTexts 

func (s *SvgIcon) DrawTexts(img *image.RGBA, opacity float64)

DrawTexts calls draw function for each text

func (*SvgIcon) SetTarget 

func (s *SvgIcon) SetTarget(x, y, w, h float64)

SetTarget sets the Transform matrix to draw within the bounds of the rectangle arguments

type SvgPath 

type SvgPath struct {
	PathStyle
	Path rasterx.Path
}

SvgPath binds a style to a path.

func (*SvgPath) Draw 

func (svgp *SvgPath) Draw(r *rasterx.Dasher, opacity float64)

Draw the compiled SvgPath into the Dasher.

func (*SvgPath) DrawTransformed 

func (svgp *SvgPath) DrawTransformed(r *rasterx.Dasher, opacity float64, t rasterx.Matrix2D)

DrawTransformed draws the compiled SvgPath into the Dasher while applying transform t.

func (*SvgPath) GetFillColor 

func (svgp *SvgPath) GetFillColor() color.Color

GetFillColor returns the fill color of the SvgPath if one is defined and otherwise returns colornames.Black

func (*SvgPath) GetLineColor 

func (svgp *SvgPath) GetLineColor() color.Color

GetLineColor returns the stroke color of the SvgPath if one is defined and otherwise returns colornames.Black

func (*SvgPath) SetFillColor 

func (svgp *SvgPath) SetFillColor(clr color.Color)

SetFillColor sets the fill color of the SvgPath

func (*SvgPath) SetLineColor 

func (svgp *SvgPath) SetLineColor(clr color.Color)

SetLineColor sets the line color of the SvgPath

type SvgText 

type SvgText struct {
	Style []xml.Attr
	Data  string
}

func (*SvgText) DrawTransformed 

func (svgt *SvgText) DrawTransformed(img *image.RGBA, opacity float64, t rasterx.Matrix2D, classes map[string]styleAttribute)

Source Files

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