init

internal/renderer/svg.go

@@ -0,0 +1,172 @@
+package renderer
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+
+	"github.com/kevin/go-jdenticon/internal/engine"
+)
+
+// SVGPath represents an SVG path element
+type SVGPath struct {
+	data strings.Builder
+}
+
+// AddPolygon adds a polygon to the SVG path
+func (p *SVGPath) AddPolygon(points []engine.Point) {
+	if len(points) == 0 {
+		return
+	}
+
+	// Move to first point
+	p.data.WriteString(fmt.Sprintf("M%s %s", svgValue(points[0].X), svgValue(points[0].Y)))
+
+	// Line to subsequent points
+	for i := 1; i < len(points); i++ {
+		p.data.WriteString(fmt.Sprintf("L%s %s", svgValue(points[i].X), svgValue(points[i].Y)))
+	}
+
+	// Close path
+	p.data.WriteString("Z")
+}
+
+// AddCircle adds a circle to the SVG path
+func (p *SVGPath) AddCircle(topLeft engine.Point, size float64, counterClockwise bool) {
+	sweepFlag := "1"
+	if counterClockwise {
+		sweepFlag = "0"
+	}
+
+	radius := size / 2
+	centerX := topLeft.X + radius
+	centerY := topLeft.Y + radius
+	
+	svgRadius := svgValue(radius)
+	svgDiameter := svgValue(size)
+	svgArc := fmt.Sprintf("a%s,%s 0 1,%s ", svgRadius, svgRadius, sweepFlag)
+
+	// Move to start point (left side of circle)
+	startX := centerX - radius
+	startY := centerY
+
+	p.data.WriteString(fmt.Sprintf("M%s %s", svgValue(startX), svgValue(startY)))
+	p.data.WriteString(svgArc + svgDiameter + ",0")
+	p.data.WriteString(svgArc + "-" + svgDiameter + ",0")
+}
+
+// DataString returns the SVG path data string
+func (p *SVGPath) DataString() string {
+	return p.data.String()
+}
+
+// SVGRenderer implements the Renderer interface for SVG output
+type SVGRenderer struct {
+	*BaseRenderer
+	pathsByColor map[string]*SVGPath
+	colorOrder   []string
+}
+
+// NewSVGRenderer creates a new SVG renderer
+func NewSVGRenderer(iconSize int) *SVGRenderer {
+	return &SVGRenderer{
+		BaseRenderer: NewBaseRenderer(iconSize),
+		pathsByColor: make(map[string]*SVGPath),
+		colorOrder:   make([]string, 0),
+	}
+}
+
+// SetBackground sets the background color and opacity
+func (r *SVGRenderer) SetBackground(fillColor string, opacity float64) {
+	r.BaseRenderer.SetBackground(fillColor, opacity)
+}
+
+// BeginShape marks the beginning of a new shape with the specified color
+func (r *SVGRenderer) BeginShape(color string) {
+	r.BaseRenderer.BeginShape(color)
+	if _, exists := r.pathsByColor[color]; !exists {
+		r.pathsByColor[color] = &SVGPath{}
+		r.colorOrder = append(r.colorOrder, color)
+	}
+}
+
+// EndShape marks the end of the currently drawn shape
+func (r *SVGRenderer) EndShape() {
+	// No action needed for SVG
+}
+
+// getCurrentPath returns the current path for the active color
+func (r *SVGRenderer) getCurrentPath() *SVGPath {
+	currentColor := r.GetCurrentColor()
+	if currentColor == "" {
+		return nil
+	}
+	return r.pathsByColor[currentColor]
+}
+
+// AddPolygon adds a polygon with the current fill color to the SVG
+func (r *SVGRenderer) AddPolygon(points []engine.Point) {
+	if path := r.getCurrentPath(); path != nil {
+		path.AddPolygon(points)
+	}
+}
+
+// AddCircle adds a circle with the current fill color to the SVG
+func (r *SVGRenderer) AddCircle(topLeft engine.Point, size float64, invert bool) {
+	if path := r.getCurrentPath(); path != nil {
+		path.AddCircle(topLeft, size, invert)
+	}
+}
+
+// ToSVG generates the final SVG XML string
+func (r *SVGRenderer) ToSVG() string {
+	var svg strings.Builder
+	
+	iconSize := r.GetSize()
+	background, backgroundOp := r.GetBackground()
+
+	// SVG opening tag with namespace and dimensions
+	svg.WriteString(fmt.Sprintf(`<svg xmlns="http://www.w3.org/2000/svg" width="%d" height="%d" viewBox="0 0 %d %d">`,
+		iconSize, iconSize, iconSize, iconSize))
+
+	// Add background rectangle if specified
+	if background != "" && backgroundOp > 0 {
+		if backgroundOp >= 1.0 {
+			svg.WriteString(fmt.Sprintf(`<rect width="100%%" height="100%%" fill="%s"/>`, background))
+		} else {
+			svg.WriteString(fmt.Sprintf(`<rect width="100%%" height="100%%" fill="%s" opacity="%.2f"/>`,
+				background, backgroundOp))
+		}
+	}
+
+	// Add paths for each color (in insertion order to preserve z-order)
+	for _, color := range r.colorOrder {
+		path := r.pathsByColor[color]
+		dataString := path.DataString()
+		if dataString != "" {
+			svg.WriteString(fmt.Sprintf(`<path fill="%s" d="%s"/>`, color, dataString))
+		}
+	}
+
+	// SVG closing tag
+	svg.WriteString("</svg>")
+
+	return svg.String()
+}
+
+// svgValue rounds a float64 to one decimal place, mimicking the Jdenticon JS implementation's
+// "round half up" behavior. It also formats the number to a minimal string representation.
+func svgValue(value float64) string {
+	// Use math.Floor to replicate the "round half up" logic from the JS implementation.
+	// JavaScript: ((value * 10 + 0.5) | 0) / 10
+	rounded := math.Floor(value*10 + 0.5) / 10
+	
+	// Format to an integer string if there's no fractional part.
+	if rounded == math.Trunc(rounded) {
+		return strconv.Itoa(int(rounded))
+	}
+	
+	// Otherwise, format to one decimal place.
+	return strconv.FormatFloat(rounded, 'f', 1, 64)
+}