Experimental embed svg font functionality

draw2dsvg/fileutil.go

@@ -1,9 +1,9 @@
 package draw2dsvg
 
 import (
-	"os"
 	"encoding/xml"
 	_ "errors"
+	"os"
 )
 
 func SaveToSvgFile(filePath string, svg *Svg) error {
@@ -19,4 +19,4 @@ func SaveToSvgFile(filePath string, svg *Svg) error {
 	err = encoder.Encode(svg)
 
 	return err
-}
+}

draw2dsvg/gc.go

@@ -4,17 +4,17 @@
 package draw2dsvg
 
 import (
+	"fmt"
+	"github.com/golang/freetype/truetype"
 	"github.com/llgcode/draw2d"
 	"github.com/llgcode/draw2d/draw2dbase"
+	"golang.org/x/image/font"
+	"golang.org/x/image/math/fixed"
 	"image"
 	"log"
-	"strings"
 	"math"
-	"github.com/golang/freetype/truetype"
-	"golang.org/x/image/math/fixed"
-	"golang.org/x/image/font"
 	"strconv"
-	"fmt"
+	"strings"
 )
 
 type drawType int
@@ -133,12 +133,16 @@ func (gc *GraphicContext) drawString(text string, drawType drawType, x, y float6
 	svgText.FontSize = gc.Current.FontSize
 	svgText.X = x
 	svgText.Y = y
-	svgText.FontFamily = "" // TODO set font
+	svgText.FontFamily = gc.Current.FontData.Name
+
+	if gc.svg.fontMode == SvgFontMode {
+		gc.embedSvgFont(text)
+	}
 
 	// link to group
 	group.Texts = []*Text{&svgText}
 	left, _, right, _ := gc.GetStringBounds(text)
-	return right-left
+	return right - left
 }
 
 // Creates new group from current context
@@ -170,20 +174,59 @@ func (gc *GraphicContext) newGroup(drawType drawType) *Group {
 	return &group
 }
 
-///////////////////////////////////////
-// TODO implement following methods (or remove if not neccesary)
+// Embed svg font definition to svg tree itself
+func (gc *GraphicContext) embedSvgFont(text string) {
+	fontName := gc.Current.FontData.Name
+	gc.loadCurrentFont()
 
-// SetFontData sets the current FontData
-func (gc *GraphicContext) SetFontData(fontData draw2d.FontData) {
+	// find or create font Element
+	svgFont := (*Font)(nil)
+	for _, font := range gc.svg.Fonts {
+		if font.Name == fontName {
+			svgFont = font
+			break
+		}
+	}
+	if svgFont == nil {
+		// create new
+		svgFont = &Font{}
+		// and link
+		gc.svg.Fonts = append(gc.svg.Fonts, svgFont)
+	}
 
+	// fill with glyphs
+
+	gc.Save()
+	defer gc.Restore()
+	gc.SetFontSize(2048)
+	defer gc.SetDPI(gc.GetDPI())
+	gc.SetDPI(92)
+filling:
+	for _, rune := range text {
+		for _, g := range svgFont.Glyphs {
+			if g.Rune == Rune(rune) {
+				continue filling
+			}
+		}
+		glyph := gc.glyphCache.Fetch(gc, gc.GetFontName(), rune)
+		// glyphCache.Load indirectly calls CreateStringPath for single rune string
+
+		glypPath := glyph.Path.VerticalFlip() // svg font glyphs have oposite y axe
+		svgFont.Glyphs = append(svgFont.Glyphs, &Glyph{
+			Rune:      Rune(rune),
+			Desc:      toSvgPathDesc(glypPath),
+			HorizAdvX: glyph.Width,
+		})
+	}
+
+	// set attrs
+	svgFont.Id = "font-" + strconv.Itoa(len(gc.svg.Fonts))
+	svgFont.Name = fontName
+
+	// TODO use css @font-face with id instead of this
+	svgFont.Face = &Face{Family: fontName, Units: 2048, HorizAdvX: 2048}
 }
 
-// GetFontData gets the current FontData
-func (gc *GraphicContext) GetFontData() draw2d.FontData {
-	return draw2d.FontData{}
-}
-
-
 // NOTE following functions copied from dwra2d{img|gl}
 // TODO move them all to common draw2dbase?
 
@@ -218,7 +261,6 @@ func (gc *GraphicContext) CreateStringPath(s string, x, y float64) (cursor float
 	return x - startx
 }
 
-
 // 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.
@@ -311,7 +353,6 @@ func (gc *GraphicContext) SetFontSize(fontSize float64) {
 	gc.recalc()
 }
 
-
 ///////////////////////////////////////
 // TODO implement following methods (or remove if not neccesary)
 

draw2dsvg/svg.go

@@ -9,10 +9,22 @@ import (
 
 /* svg elements */
 
+type FontMode int
+
+const (
+	SysFontMode FontMode = 1 << iota
+	LinkFontMode
+	SvgFontMode
+	CssFontMode
+	PathFontMode
+)
+
 type Svg struct {
-	XMLName xml.Name `xml:"svg"`
-	Xmlns   string   `xml:"xmlns,attr"`
-	Groups  []*Group `xml:"g"`
+	XMLName  xml.Name `xml:"svg"`
+	Xmlns    string   `xml:"xmlns,attr"`
+	Fonts    []*Font  `xml:"defs>font"`
+	Groups   []*Group `xml:"g"`
+	fontMode FontMode
 	FillStroke
 }
 
@@ -20,6 +32,7 @@ func NewSvg() *Svg {
 	return &Svg{
 		Xmlns:      "http://www.w3.org/2000/svg",
 		FillStroke: FillStroke{Fill: "none", Stroke: "none"},
+		fontMode:   SvgFontMode,
 	}
 }
 
@@ -45,8 +58,41 @@ type Text struct {
 	Style      string  `xml:"style,attr,omitempty"`
 }
 
+type Font struct {
+	Identity
+	Face   *Face    `xml:"font-face"`
+	Glyphs []*Glyph `xml:"glyph"`
+}
+
+type Face struct {
+	Family    string  `xml:"font-family,attr"`
+	Units     int     `xml:"units-per-em,attr"`
+	HorizAdvX float64 `xml:"horiz-adv-x,attr"`
+	// TODO add other attrs, like style, variant, weight...
+}
+
+type Glyph struct {
+	Rune      Rune    `xml:"unicode,attr"`
+	Desc      string  `xml:"d,attr"`
+	HorizAdvX float64 `xml:"horiz-adv-x,attr"`
+}
+
+type Rune rune
+
+func (r Rune) MarshalXMLAttr(name xml.Name) (xml.Attr, error) {
+	return xml.Attr{
+		Name:  name,
+		Value: string(rune(r)),
+	}, nil
+}
+
 /* shared attrs */
 
+type Identity struct {
+	Id   string `xml:"id,attr"`
+	Name string `xml:"name,attr"`
+}
+
 type Position struct {
 	X float64 `xml:"x,attr,omitempty"`
 	Y float64 `xml:"y,attr,omitempty"`

draw2dsvg/xml_test.go

@@ -31,6 +31,7 @@ func TestXml(t *testing.T) {
 	}}
 
 	expectedOut := `<svg xmlns="http://www.w3.org/2000/svg" fill="none" stroke="none">
+  <defs></defs>
   <g>
     <g></g>
     <g></g>

path.go

@@ -190,3 +190,34 @@ func (p *Path) String() string {
 	}
 	return s
 }
+
+// Returns new Path with flipped y axes
+func (path *Path) VerticalFlip() *Path {
+	p := path.Copy()
+	j := 0
+	for _, cmd := range p.Components {
+		switch cmd {
+		case MoveToCmp, LineToCmp:
+			p.Points[j+1] = -p.Points[j+1]
+			j = j + 2
+		case QuadCurveToCmp:
+			p.Points[j+1] = -p.Points[j+1]
+			p.Points[j+3] = -p.Points[j+3]
+			j = j + 4
+		case CubicCurveToCmp:
+			p.Points[j+1] = -p.Points[j+1]
+			p.Points[j+3] = -p.Points[j+3]
+			p.Points[j+5] = -p.Points[j+5]
+			j = j + 6
+		case ArcToCmp:
+			p.Points[j+1] = -p.Points[j+1]
+			p.Points[j+3] = -p.Points[j+3]
+			p.Points[j+4] = -p.Points[j+4] // start angle
+			p.Points[j+5] = -p.Points[j+5] // angle
+			j = j + 6
+		case CloseCmp:
+		}
+	}
+	p.y = -p.y
+	return p
+}

samples/geometry/geometry.go

@@ -189,6 +189,7 @@ func CubicCurve(gc draw2d.GraphicContext, x, y, width, height float64) {
 }
 
 // FillString draws a filled and stroked string.
+// And filles/stroked path created from string. Which may have different - unselectable -  output in non raster gc implementations.
 func FillString(gc draw2d.GraphicContext, x, y, width, height float64) {
 	sx, sy := width/100, height/100
 	gc.Save()
@@ -215,6 +216,14 @@ func FillString(gc draw2d.GraphicContext, x, y, width, height float64) {
 	gc.SetStrokeColor(color.NRGBA{0x33, 0x33, 0xff, 0xff})
 	gc.SetLineWidth(height / 100)
 	gc.StrokeString("Hug")
+
+	gc.Translate(-(w + sx), sy*24)
+	w = gc.CreateStringPath("Hug", 0, 0)
+	gc.Fill()
+	gc.Translate(w+sx, 0)
+	gc.CreateStringPath("Hug", 0, 0)
+	path := gc.GetPath()
+	gc.Stroke((&path).VerticalFlip())
 	gc.Restore()
 }