removing 3rd party deps.

vector_renderer.go

@@ -5,37 +5,44 @@ import (
 	"fmt"
 	"image/color"
 	"io"
+	"math"
 	"strings"
 
 	"golang.org/x/image/font"
 
-	"github.com/ajstarks/svgo"
 	"github.com/golang/freetype/truetype"
 )
 
 // SVG returns a new png/raster renderer.
-func SVG(width, height int) Renderer {
+func SVG(width, height int) (Renderer, error) {
 	buffer := bytes.NewBuffer([]byte{})
-	canvas := svg.New(buffer)
+	canvas := newCanvas(buffer)
 	canvas.Start(width, height)
 	return &vectorRenderer{
 		b: buffer,
 		c: canvas,
 		s: &Style{},
 		p: []string{},
-	}
+	}, nil
 }
 
 // vectorRenderer renders chart commands to a bitmap.
 type vectorRenderer struct {
-	b  *bytes.Buffer
-	c  *svg.SVG
-	s  *Style
-	f  *truetype.Font
-	p  []string
-	fc *font.Drawer
+	dpi float64
+	b   *bytes.Buffer
+	c   *canvas
+	s   *Style
+	f   *truetype.Font
+	p   []string
+	fc  *font.Drawer
 }
 
+// SetDPI implements the interface method.
+func (vr *vectorRenderer) SetDPI(dpi float64) {
+	vr.dpi = dpi
+}
+
+// SetStrokeColor implements the interface method.
 func (vr *vectorRenderer) SetStrokeColor(c color.RGBA) {
 	vr.s.StrokeColor = c
 }
@@ -130,20 +137,18 @@ func (vr *vectorRenderer) Text(body string, x, y int) {
 }
 
 // MeasureText uses the truetype font drawer to measure the width of text.
-func (vr *vectorRenderer) MeasureText(body string) int {
-	if vr.fc == nil && vr.f != nil {
+func (vr *vectorRenderer) MeasureText(body string) (width, height int) {
+	if vr.f != nil {
 		vr.fc = &font.Drawer{
 			Face: truetype.NewFace(vr.f, &truetype.Options{
-				DPI:  DefaultDPI,
+				DPI:  vr.dpi,
 				Size: vr.s.FontSize,
 			}),
 		}
+		width = vr.fc.MeasureString(body).Ceil()
+		height = int(math.Ceil(vr.s.FontSize))
 	}
-	if vr.fc != nil {
-		dimensions := vr.fc.MeasureString(body)
-		return dimensions.Floor()
-	}
-	return 0
+	return
 }
 
 func (vr *vectorRenderer) Save(w io.Writer) error {
@@ -151,3 +156,49 @@ func (vr *vectorRenderer) Save(w io.Writer) error {
 	_, err := w.Write(vr.b.Bytes())
 	return err
 }
+
+func newCanvas(w io.Writer) *canvas {
+	return &canvas{
+		w: w,
+	}
+}
+
+type canvas struct {
+	w      io.Writer
+	width  int
+	height int
+}
+
+func (c *canvas) Start(width, height int) {
+	c.width = width
+	c.height = height
+	c.w.Write([]byte(fmt.Sprintf(`<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="%d" height="%d">\n`, c.width, c.height)))
+}
+
+func (c *canvas) Path(d string, style ...string) {
+	if len(style) > 0 {
+		c.w.Write([]byte(fmt.Sprintf(`<path d="%s" style="%s"/>\n`, d, style[0])))
+	} else {
+		c.w.Write([]byte(fmt.Sprintf(`<path d="%s"/>\n`, d)))
+	}
+}
+
+func (c *canvas) Text(x, y int, body string, style ...string) {
+	if len(style) > 0 {
+		c.w.Write([]byte(fmt.Sprintf(`<text x="%d" y="%d" style="%s">%s</text>`, x, y, style[0], body)))
+	} else {
+		c.w.Write([]byte(fmt.Sprintf(`<text x="%d" y="%d">%s</text>`, x, y, body)))
+	}
+}
+
+func (c *canvas) Circle(x, y, r int, style ...string) {
+	if len(style) > 0 {
+		c.w.Write([]byte(fmt.Sprintf(`<circle cx="%d" cy="%d" r="%d" style="%s">`, x, y, r, style[0])))
+	} else {
+		c.w.Write([]byte(fmt.Sprintf(`<circle cx="%d" cy="%d" r="%d">`, x, y, r)))
+	}
+}
+
+func (c *canvas) End() {
+	c.w.Write([]byte("</svg>"))
+}