draw2dsvg

package
v0.0.0-...-ee6987b Latest Latest
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 Go to latest Published: Mar 22, 2024 License: BSD-2-Clause Imports: 19 Imported by: 11

Documentation

Overview

Package draw2svg provides a graphic context that can draw vector graphics and text on svg file.

Quick Start The following Go code geneartes a simple drawing and saves it to a svg document: TODO

NOTE that this is identical copy of draw2dgl/text.go and draw2dimg/text.go

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func DrawContour 

func DrawContour(path draw2d.PathBuilder, ps []truetype.Point, dx, dy float64)

DrawContour draws the given closed contour at the given sub-pixel offset.

func SaveToSvgFile 

func SaveToSvgFile(filePath string, svg *Svg) error

func WriteSvg 

func WriteSvg(w io.Writer, svg *Svg) error

Types

type Dimension 

type Dimension struct {
	Width  string `xml:"width,attr"`
	Height string `xml:"height,attr"`
}

type Face 

type Face struct {
	Family    string  `xml:"font-family,attr"`
	Units     int     `xml:"units-per-em,attr"`
	HorizAdvX float64 `xml:"horiz-adv-x,attr"`
}

type FillStroke 

type FillStroke struct {
	Fill     string `xml:"fill,attr,omitempty"`
	FillRule string `xml:"fill-rule,attr,omitempty"`

	Stroke           string `xml:"stroke,attr,omitempty"`
	StrokeWidth      string `xml:"stroke-width,attr,omitempty"`
	StrokeLinecap    string `xml:"stroke-linecap,attr,omitempty"`
	StrokeLinejoin   string `xml:"stroke-linejoin,attr,omitempty"`
	StrokeDasharray  string `xml:"stroke-dasharray,attr,omitempty"`
	StrokeDashoffset string `xml:"stroke-dashoffset,attr,omitempty"`
}

type Font 

type Font struct {
	Identity
	Face   *Face    `xml:"font-face"`
	Glyphs []*Glyph `xml:"glyph"`
}

type FontExtents 

type FontExtents struct {
	// Ascent is the distance that the text
	// extends above the baseline.
	Ascent float64

	// Descent is the distance that the text
	// extends below the baseline.  The descent
	// is given as a negative value.
	Descent float64

	// Height is the distance from the lowest
	// descending point to the highest ascending
	// point.
	Height float64
}

FontExtents contains font metric information.

func Extents 

func Extents(font *truetype.Font, size float64) FontExtents

Extents returns the FontExtents for a font. TODO needs to read this https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/Chap2.html#intro

type FontMode 

type FontMode int
const (
	// Does nothing special
	// Makes sense only for common system fonts
	SysFontMode FontMode = 1 << iota

	// Links font files in css def
	// Requires distribution of font files with outputed svg
	LinkFontMode // TODO implement

	// Embeds glyphs definition in svg file itself in svg font format
	// Has poor browser support
	SvgFontMode

	// Embeds font definiton in svg file itself in woff format as part of css def
	CssFontMode // TODO implement

	// Converts texts to paths
	PathFontMode
)

Modes of font handling in svg

type Glyph 

type Glyph struct {
	Rune      Rune    `xml:"unicode,attr"`
	Desc      string  `xml:"d,attr"`
	HorizAdvX float64 `xml:"horiz-adv-x,attr"`
}

type GraphicContext 

type GraphicContext struct {
	*draw2dbase.StackGraphicContext
	FontCache draw2d.FontCache

	DPI int
	// contains filtered or unexported fields
}

GraphicContext implements the draw2d.GraphicContext interface It provides draw2d with a svg backend

func NewGraphicContext 

func NewGraphicContext(svg *Svg) *GraphicContext

func (*GraphicContext) Clear 

func (gc *GraphicContext) Clear()

Clear fills the current canvas with a default transparent color

func (*GraphicContext) ClearRect 

func (gc *GraphicContext) ClearRect(x1, y1, x2, y2 int)

ClearRect fills the specified rectangle with a default transparent color

func (*GraphicContext) CreateStringPath 

func (gc *GraphicContext) CreateStringPath(s string, x, y float64) (cursor float64)

CreateStringPath creates a path from the string s at x, y, and returns the string width. The text is placed so that the left edge of the em square of the first character of s and the baseline intersect at x, y. The majority of the affected pixels will be above and to the right of the point, but some may be below or to the left. For example, drawing a string that starts with a 'J' in an italic font may affect pixels below and left of the point.

func (*GraphicContext) DrawImage 

func (gc *GraphicContext) DrawImage(image image.Image)

DrawImage draws the raster image in the current canvas

func (*GraphicContext) Fill 

func (gc *GraphicContext) Fill(paths ...*draw2d.Path)

Fill fills the paths with the color specified by SetFillColor

func (*GraphicContext) FillString 

func (gc *GraphicContext) FillString(text string) (cursor float64)

FillString draws the text at point (0, 0)

func (*GraphicContext) FillStringAt 

func (gc *GraphicContext) FillStringAt(text string, x, y float64) (cursor float64)

FillStringAt draws the text at the specified point (x, y)

func (*GraphicContext) FillStroke 

func (gc *GraphicContext) FillStroke(paths ...*draw2d.Path)

FillStroke first fills the paths and than strokes them

func (*GraphicContext) GetDPI 

func (gc *GraphicContext) GetDPI() int

func (*GraphicContext) GetStringBounds 

func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64)

GetStringBounds returns the approximate pixel bounds of the string s at x, y. The the left edge of the em square of the first character of s and the baseline intersect at 0, 0 in the returned coordinates. Therefore the top and left coordinates may well be negative.

func (*GraphicContext) Restore 

func (gc *GraphicContext) Restore()

Restore remove the current context and restore the last one

func (*GraphicContext) Save 

func (gc *GraphicContext) Save()

Save the context and push it to the context stack

func (*GraphicContext) SetDPI 

func (gc *GraphicContext) SetDPI(dpi int)

func (*GraphicContext) SetFont 

func (gc *GraphicContext) SetFont(font *truetype.Font)

SetFont sets the font used to draw text.

func (*GraphicContext) SetFontSize 

func (gc *GraphicContext) SetFontSize(fontSize float64)

SetFontSize sets the font size in points (as in “a 12 point font”).

func (*GraphicContext) Stroke 

func (gc *GraphicContext) Stroke(paths ...*draw2d.Path)

Stroke strokes the paths with the color specified by SetStrokeColor

func (*GraphicContext) StrokeString 

func (gc *GraphicContext) StrokeString(text string) (cursor float64)

StrokeString draws the contour of the text at point (0, 0)

func (*GraphicContext) StrokeStringAt 

func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor float64)

StrokeStringAt draws the contour of the text at point (x, y)

type Group 

type Group struct {
	FillStroke
	Transform string   `xml:"transform,attr,omitempty"`
	Groups    []*Group `xml:"g"`
	Paths     []*Path  `xml:"path"`
	Texts     []*Text  `xml:"text"`
	Image     *Image   `xml:"image"`
	Mask      string   `xml:"mask,attr,omitempty"`
}

type Identity 

type Identity struct {
	Id   string `xml:"id,attr"`
	Name string `xml:"name,attr"`
}

type Image 

type Image struct {
	Position
	Dimension
	Href string `xml:"href,attr"`
}

type Mask 

type Mask struct {
	Identity
	Position
	Dimension
}

func (Mask) MarshalXML 

func (m Mask) MarshalXML(e *xml.Encoder, start xml.StartElement) error

type Path 

type Path struct {
	FillStroke
	Desc string `xml:"d,attr"`
}

type Position 

type Position struct {
	X float64 `xml:"x,attr,omitempty"`
	Y float64 `xml:"y,attr,omitempty"`
}

type Rect 

type Rect struct {
	Position
	Dimension
	FillStroke
}

type Rune 

type Rune rune

func (Rune) MarshalXMLAttr 

func (r Rune) MarshalXMLAttr(name xml.Name) (xml.Attr, error)

type Svg 

type Svg struct {
	XMLName  xml.Name `xml:"svg"`
	Xmlns    string   `xml:"xmlns,attr"`
	Width    string   `xml:"width,attr,omitempty"`
	Height   string   `xml:"height,attr,omitempty"`
	ViewBox  string   `xml:"viewBox,attr,omitempty"`
	Fonts    []*Font  `xml:"defs>font"`
	Masks    []*Mask  `xml:"defs>mask"`
	Groups   []*Group `xml:"g"`
	FontMode FontMode `xml:"-"`
	FillStroke
}

func NewSvg 

func NewSvg() *Svg

type Text 

type Text struct {
	FillStroke
	Position
	FontSize   float64 `xml:"font-size,attr,omitempty"`
	FontFamily string  `xml:"font-family,attr,omitempty"`
	Text       string  `xml:",innerxml"`
	Style      string  `xml:"style,attr,omitempty"`
}

Source Files

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