Implement basic text drawing in svg context
fonts, bounds and string paths not yet implemented
This commit is contained in:
Drahoslav
parent
215a761ccb
commit
90f962641f
3 changed files with 109 additions and 83 deletions
156
draw2dsvg/gc.go
156
draw2dsvg/gc.go
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@ -46,9 +46,6 @@ func NewGraphicContext(svg *Svg) *GraphicContext {
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// Clear fills the current canvas with a default transparent color
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func (gc *GraphicContext) Clear() {
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gc.svg.Groups = nil
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gc.svg.Groups = append(gc.svg.Groups, Group{
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// TODO add background color?
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})
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}
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// Stroke strokes the paths with the color specified by SetStrokeColor
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@ -69,47 +66,102 @@ func (gc *GraphicContext) FillStroke(paths ...*draw2d.Path) {
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gc.Current.Path.Clear()
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}
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// FillString draws the text at point (0, 0)
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func (gc *GraphicContext) FillString(text string) (cursor float64) {
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return gc.FillStringAt(text, 0, 0)
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}
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// FillStringAt draws the text at the specified point (x, y)
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func (gc *GraphicContext) FillStringAt(text string, x, y float64) (cursor float64) {
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return gc.drawString(text, filled, x, y)
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}
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// StrokeString draws the contour of the text at point (0, 0)
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func (gc *GraphicContext) StrokeString(text string) (cursor float64) {
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return gc.StrokeStringAt(text, 0, 0)
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}
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// StrokeStringAt draws the contour of the text at point (x, y)
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func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor float64) {
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return gc.drawString(text, stroked, x, y)
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}
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// Save the context and push it to the context stack
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func (gc *GraphicContext) Save() {
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gc.StackGraphicContext.Save()
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// TODO use common transformation group for multiple elements
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}
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// Restore remove the current context and restore the last one
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func (gc *GraphicContext) Restore() {
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gc.StackGraphicContext.Restore()
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// TODO use common transformation group for multiple elements
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}
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// private funcitons
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func (gc *GraphicContext) drawPaths(drawType drawType, paths ...*draw2d.Path) {
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// create elements
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svgPath := Path{}
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group := gc.newGroup(drawType)
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// set attrs to path element
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paths = append(paths, gc.Current.Path)
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svgPathsDesc := make([]string, len(paths))
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// multiple pathes has to be joined to single svg path description
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// because fill-rule wont work for whole group as excepted
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for i, path := range paths {
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svgPathsDesc[i] = toSvgPathDesc(path)
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}
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svgPath.Desc = strings.Join(svgPathsDesc, " ")
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// link to group
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group.Paths = []*Path{&svgPath}
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}
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func (gc *GraphicContext) drawString(text string, drawType drawType, x, y float64) float64 {
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// create elements
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svgText := Text{}
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group := gc.newGroup(drawType)
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// set attrs to text element
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svgText.Text = text
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svgText.X = x
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svgText.Y = y
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// TODO set font
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// link to group
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(*group).Texts = []*Text{&svgText}
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return 0
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}
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// Creates new group from current context
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// append it to svg and return
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func (gc *GraphicContext) newGroup(drawType drawType) *Group {
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group := Group{}
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// set attrs to path
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{
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paths = append(paths, gc.Current.Path)
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svgPathsDesc := make([]string, len(paths))
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// multiple pathes has to be joined to single svg path description
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// because fill-rule wont work for whole group as excepted
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for i, path := range paths {
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svgPathsDesc[i] = toSvgPathDesc(path)
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}
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svgPath.Desc = strings.Join(svgPathsDesc, " ")
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}
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// set attrs to group
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{
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if drawType&stroked == stroked {
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group.Stroke = toSvgRGBA(gc.Current.StrokeColor)
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group.StrokeWidth = toSvgLength(gc.Current.LineWidth)
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group.StrokeLinecap = gc.Current.Cap.String()
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group.StrokeLinejoin = gc.Current.Join.String()
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if len(gc.Current.Dash) > 0 {
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group.StrokeDasharray = toSvgArray(gc.Current.Dash)
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group.StrokeDashoffset = toSvgLength(gc.Current.DashOffset)
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}
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if drawType&stroked == stroked {
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group.Stroke = toSvgRGBA(gc.Current.StrokeColor)
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group.StrokeWidth = toSvgLength(gc.Current.LineWidth)
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group.StrokeLinecap = gc.Current.Cap.String()
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group.StrokeLinejoin = gc.Current.Join.String()
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if len(gc.Current.Dash) > 0 {
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group.StrokeDasharray = toSvgArray(gc.Current.Dash)
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group.StrokeDashoffset = toSvgLength(gc.Current.DashOffset)
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}
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if drawType&filled == filled {
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group.Fill = toSvgRGBA(gc.Current.FillColor)
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group.FillRule = toSvgFillRule(gc.Current.FillRule)
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}
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group.Transform = toSvgTransform(gc.Current.Tr)
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}
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// link elements
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group.Paths = []Path{svgPath}
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gc.svg.Groups = append(gc.svg.Groups, group)
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if drawType&filled == filled {
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group.Fill = toSvgRGBA(gc.Current.FillColor)
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group.FillRule = toSvgFillRule(gc.Current.FillRule)
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}
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group.Transform = toSvgTransform(gc.Current.Tr)
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// link
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gc.svg.Groups = append(gc.svg.Groups, &group)
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return &group
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}
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///////////////////////////////////////
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@ -135,18 +187,6 @@ func (gc *GraphicContext) DrawImage(image image.Image) {
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}
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// Save the context and push it to the context stack
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func (gc *GraphicContext) Save() {
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gc.StackGraphicContext.Save()
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// TODO use common transformation group for multiple elements
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}
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// Restore remove the current context and restore the last one
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func (gc *GraphicContext) Restore() {
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gc.StackGraphicContext.Restore()
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// TODO use common transformation group for multiple elements
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}
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// ClearRect fills the specified rectangle with a default transparent color
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func (gc *GraphicContext) ClearRect(x1, y1, x2, y2 int) {
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@ -171,23 +211,3 @@ func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom fl
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func (gc *GraphicContext) CreateStringPath(text string, x, y float64) (cursor float64) {
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return 0
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}
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// FillString draws the text at point (0, 0)
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func (gc *GraphicContext) FillString(text string) (cursor float64) {
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return 0
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}
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// FillStringAt draws the text at the specified point (x, y)
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func (gc *GraphicContext) FillStringAt(text string, x, y float64) (cursor float64) {
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return 0
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}
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// StrokeString draws the contour of the text at point (0, 0)
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func (gc *GraphicContext) StrokeString(text string) (cursor float64) {
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return 0
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}
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// StrokeStringAt draws the contour of the text at point (x, y)
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func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor float64) {
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return 0
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}
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@ -12,16 +12,16 @@ import (
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type Svg struct {
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XMLName xml.Name `xml:"svg"`
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Xmlns string `xml:"xmlns,attr"`
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Groups []Group `xml:"g"`
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Groups []*Group `xml:"g"`
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FillStroke
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}
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type Group struct {
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FillStroke
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Transform string `xml:"transform,attr,omitempty"`
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Groups []Group `xml:"g"`
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Paths []Path `xml:"path"`
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Texts []Text `xml:"text"`
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Transform string `xml:"transform,attr,omitempty"`
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Groups []*Group `xml:"g"`
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Paths []*Path `xml:"path"`
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Texts []*Text `xml:"text"`
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}
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type Path struct {
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@ -31,12 +31,18 @@ type Path struct {
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type Text struct {
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FillStroke
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Position
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Text string `xml:",innerxml"`
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Style string `xml:"style,attr,omitempty"`
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}
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/* shared attrs */
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type Position struct {
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X float64 `xml:"x,attr,omitempty"`
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Y float64 `xml:"y,attr,omitempty"`
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}
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type FillStroke struct {
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Fill string `xml:"fill,attr,omitempty"`
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FillRule string `xml:"fill-rule,attr,omitempty"`
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@ -15,18 +15,18 @@ import (
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func TestXml(t *testing.T) {
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svg := NewSvg()
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svg.Groups = []Group{Group{
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Groups: []Group{
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Group{}, // nested groups
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Group{},
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svg.Groups = []*Group{&Group{
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Groups: []*Group{
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&Group{}, // nested groups
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&Group{},
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},
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Texts: []Text{
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Text{Text: "Hello"}, // text
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Text{Text: "world", Style: "opacity: 0.5"}, // text with style
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Texts: []*Text{
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&Text{Text: "Hello"}, // text
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&Text{Text: "world", Style: "opacity: 0.5"}, // text with style
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},
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Paths: []Path{
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Path{Desc: "M100,200 C100,100 250,100 250,200 S400,300 400,200"}, // simple path
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Path{}, // empty path
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Paths: []*Path{
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&Path{Desc: "M100,200 C100,100 250,100 250,200 S400,300 400,200"}, // simple path
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&Path{}, // empty path
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},
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}}
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