Redesign icon: wood texture shield with darken-blended Syncthing motif

Replace procedural icon renderer with pre-rendered textured icons:
- Use Stammtisch wood texture as shield face (crop tabletop planks)
- Apply Syncthing motif via darken blend ("warpaint on wood" effect)
- Fix Syncthing logo geometry: asymmetric node placement (76°/116°/168°
  gaps) with offset hub, matching the official SVG
- Metal rim with rivets and directional lighting
- Embed pre-rendered PNGs via go:embed (no runtime rendering)
- Icon generator in cmd/icongen/ takes wood texture as input

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cmd/icongen/main.go

@@ -1,165 +1,447 @@
-// Generates static icon assets for the SyncWarden project.
-// Run: go run ./cmd/icongen/
+// Icon generator for SyncWarden.
+// Uses the Stammtisch wood texture as the shield face and applies
+// the Syncthing network motif with a darken blend ("warpaint on wood").
+//
+// Usage: go run ./cmd/icongen/ -wood /path/to/stammtisch.png
 package main
 
 import (
 	"bytes"
 	"encoding/binary"
+	"flag"
 	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
 	"image/png"
+	"math"
 	"os"
 	"path/filepath"
 
 	"github.com/fogleman/gg"
-
-	"git.davoryn.de/calic/syncwarden/internal/icons"
+	xdraw "golang.org/x/image/draw"
 )
 
+// State colors (must match internal/icons/states.go)
+var stateColors = []struct {
+	name  string
+	color color.RGBA
+}{
+	{"idle", color.RGBA{76, 175, 80, 255}},
+	{"syncing", color.RGBA{33, 150, 243, 255}},
+	{"paused", color.RGBA{158, 158, 158, 255}},
+	{"error", color.RGBA{244, 67, 54, 255}},
+	{"disconnected", color.RGBA{97, 97, 97, 255}},
+}
+
 func main() {
-	dir := filepath.Join("assets")
-	os.MkdirAll(dir, 0755)
+	woodPath := flag.String("wood", "", "path to wood texture PNG (stammtisch.png)")
+	flag.Parse()
 
-	// Generate PNGs at standard icon sizes (idle/green as canonical)
-	sizes := []int{16, 32, 48, 64, 128, 256, 512}
-	pngEntries := make(map[int][]byte) // size → PNG data
-
-	for _, sz := range sizes {
-		data, err := icons.RenderPNG(icons.StateIdle, sz)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "error rendering %d: %v\n", sz, err)
-			continue
+	if *woodPath == "" {
+		for _, p := range []string{
+			"/tmp/stammtisch/stammtisch.png",
+			filepath.Join(os.TempDir(), "stammtisch", "stammtisch.png"),
+		} {
+			if _, err := os.Stat(p); err == nil {
+				*woodPath = p
+				break
+			}
 		}
-		pngEntries[sz] = data
-
-		fname := fmt.Sprintf("icon-%d.png", sz)
-		fpath := filepath.Join(dir, fname)
-		if err := os.WriteFile(fpath, data, 0644); err != nil {
-			fmt.Fprintf(os.Stderr, "error writing %s: %v\n", fpath, err)
-			continue
+		if *woodPath == "" {
+			fmt.Fprintln(os.Stderr, "wood texture not found; provide -wood flag")
+			os.Exit(1)
 		}
-		fmt.Printf("  %s (%d bytes)\n", fpath, len(data))
 	}
 
-	// Generate multi-size .ico (16, 32, 48, 256)
-	icoSizes := []int{16, 32, 48, 256}
-	icoData := buildMultiICO(icoSizes, pngEntries)
-	icoPath := filepath.Join(dir, "syncwarden.ico")
-	if err := os.WriteFile(icoPath, icoData, 0644); err != nil {
-		fmt.Fprintf(os.Stderr, "error writing ico: %v\n", err)
-	} else {
-		fmt.Printf("  %s (%d bytes)\n", icoPath, len(icoData))
+	woodFull, err := loadPNG(*woodPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "load wood: %v\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("Wood texture: %dx%d\n", woodFull.Bounds().Dx(), woodFull.Bounds().Dy())
+
+	// Crop to just the flat plank surface of the tabletop.
+	// The wooden planks span roughly x=180..840, y=100..370 in the 1024×1024 image.
+	// Crop that rectangle, then scale to a square so wood fills the entire shield face.
+	woodRect := cropRect(woodFull, 200, 130, 820, 380)
+	woodImg := scaleImage(woodRect, 880, 880)
+
+	// --- Tray icons (64px, all 5 states) → internal/icons/ ---
+	trayDir := filepath.Join("internal", "icons")
+	for _, st := range stateColors {
+		img := renderShield(woodImg, st.color, 64)
+		path := filepath.Join(trayDir, "tray_"+st.name+".png")
+		savePNG(img, path)
+		fmt.Printf("  %s\n", path)
 	}
 
-	// Generate a large composited preview showing all states
-	previewPath := filepath.Join(dir, "icon-preview.png")
-	generatePreview(previewPath)
+	// --- Static assets (idle/green, multiple sizes) → assets/ ---
+	assetsDir := "assets"
+	os.MkdirAll(assetsDir, 0755)
+	idle := stateColors[0].color
+
+	icoEntries := map[int][]byte{}
+	for _, sz := range []int{16, 32, 48, 64, 128, 256, 512} {
+		img := renderShield(woodImg, idle, sz)
+		path := filepath.Join(assetsDir, fmt.Sprintf("icon-%d.png", sz))
+		data := savePNG(img, path)
+		icoEntries[sz] = data
+		fmt.Printf("  %s (%d bytes)\n", path, len(data))
+	}
+
+	// Multi-size .ico
+	icoPath := filepath.Join(assetsDir, "syncwarden.ico")
+	writeMultiICO(icoPath, icoEntries, []int{16, 32, 48, 256})
+	fmt.Printf("  %s\n", icoPath)
+
+	// Preview sheet (all states at 128px)
+	previewPath := filepath.Join(assetsDir, "icon-preview.png")
+	generatePreview(woodImg, previewPath)
+	fmt.Printf("  %s\n", previewPath)
 
 	fmt.Println("Done.")
 }
 
-func buildMultiICO(sizes []int, pngs map[int][]byte) []byte {
-	count := 0
-	for _, sz := range sizes {
-		if _, ok := pngs[sz]; ok {
-			count++
+// ─── Shield Rendering ─────────────────────────────────────────────────────────
+
+func renderShield(wood image.Image, motifColor color.RGBA, size int) *image.RGBA {
+	s := float64(size)
+	cx, cy := s/2, s/2
+	shieldR := s * 0.47
+	rimW := math.Max(2.5, s*0.058)
+	faceR := shieldR - rimW
+
+	out := image.NewRGBA(image.Rect(0, 0, size, size))
+
+	// Layer 1: Metal rim
+	rimDc := gg.NewContext(size, size)
+	drawRim(rimDc, cx, cy, shieldR, rimW, s)
+	draw.Draw(out, out.Bounds(), rimDc.Image(), image.Point{}, draw.Over)
+
+	// Layer 2: Wood face (circular crop of texture) + darken motif blend
+	woodFace := renderWoodFaceWithMotif(wood, motifColor, size, cx, cy, faceR)
+	draw.Draw(out, out.Bounds(), woodFace, image.Point{}, draw.Over)
+
+	// Layer 3: Rivets on top
+	if size >= 32 {
+		rivetDc := gg.NewContext(size, size)
+		count := 16
+		if size < 64 {
+			count = 10
+		}
+		if size < 48 {
+			count = 8
+		}
+		drawRivets(rivetDc, cx, cy, shieldR-rimW*0.5, s, count)
+		draw.Draw(out, out.Bounds(), rivetDc.Image(), image.Point{}, draw.Over)
+	}
+
+	return out
+}
+
+func renderWoodFaceWithMotif(wood image.Image, motifColor color.RGBA, size int, cx, cy, faceR float64) *image.RGBA {
+	faceDiam := int(math.Ceil(faceR * 2))
+	woodScaled := scaleImage(wood, faceDiam, faceDiam)
+
+	// Create motif mask using gg (white shapes on transparent)
+	maskDc := gg.NewContext(size, size)
+	maskDc.SetColor(color.White)
+	drawSyncthingMotif(maskDc, cx, cy, faceR)
+	maskImg := maskDc.Image()
+
+	fOX := cx - faceR
+	fOY := cy - faceR
+
+	face := image.NewRGBA(image.Rect(0, 0, size, size))
+
+	for py := 0; py < size; py++ {
+		for px := 0; px < size; px++ {
+			dx := float64(px) - cx
+			dy := float64(py) - cy
+			dist := math.Sqrt(dx*dx + dy*dy)
+			if dist > faceR+0.5 {
+				continue
+			}
+
+			wx := int(float64(px) - fOX)
+			wy := int(float64(py) - fOY)
+			if wx < 0 || wx >= faceDiam || wy < 0 || wy >= faceDiam {
+				continue
+			}
+
+			r, g, b, _ := woodScaled.At(wx, wy).RGBA()
+			wc := color.RGBA{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), 255}
+
+			// Anti-alias circle edge
+			alpha := 1.0
+			if dist > faceR-0.5 {
+				alpha = math.Max(0, faceR+0.5-dist)
+			}
+
+			// Check motif mask → darken blend
+			_, _, _, ma := maskImg.At(px, py).RGBA()
+			maskA := float64(ma) / 65535.0
+
+			final := wc
+			if maskA > 0.01 {
+				darkened := darkenBlend(wc, motifColor)
+				final = lerpColor(wc, darkened, maskA)
+			}
+
+			final.A = uint8(alpha * 255)
+			face.SetRGBA(px, py, final)
 		}
 	}
 
-	const headerSize = 6
-	const entrySize = 16
-	dataOffset := headerSize + entrySize*count
+	return face
+}
 
-	buf := new(bytes.Buffer)
+// ─── Syncthing Motif (Correct Asymmetric Geometry from Official SVG) ──────────
 
-	// ICONDIR header
-	binary.Write(buf, binary.LittleEndian, uint16(0))     // Reserved
-	binary.Write(buf, binary.LittleEndian, uint16(1))     // Type: icon
-	binary.Write(buf, binary.LittleEndian, uint16(count)) // Count
+// Geometry extracted from the official Syncthing SVG (viewBox 117.3×117.3):
+//
+//   Ring center:  (58.7, 58.5)    ≈ shield center
+//   Ring radius:  43.7
+//   Hub center:   (67.5, 64.4)    offset right+down from ring center
+//   Node 1:       angle ≈ -26°    (top-right)
+//   Node 2:       angle ≈  50°    (bottom-right)
+//   Node 3:       angle ≈ 166°    (left)
+//   Stroke width: 6
+//
+// Gaps: 76°, 116°, 168° — distinctly asymmetric, gives the "spinning" feel.
 
-	// Calculate offsets
-	offset := dataOffset
+func drawSyncthingMotif(dc *gg.Context, cx, cy, faceR float64) {
+	ringR := faceR * 0.62
+	hubX := cx + ringR*0.201
+	hubY := cy + ringR*0.135
+
+	strokeW := ringR * 0.14
+	nodeR := ringR * 0.125
+	hubR := ringR * 0.155
+
+	dc.SetLineWidth(strokeW)
+	dc.SetLineCap(gg.LineCapRound)
+
+	// Outer ring
+	dc.DrawCircle(cx, cy, ringR)
+	dc.Stroke()
+
+	// Three outer nodes + spokes to hub (asymmetric angles)
+	nodeAngles := [3]float64{-26.2, 50.2, 165.9}
+	for _, deg := range nodeAngles {
+		rad := deg * math.Pi / 180
+		nx := cx + ringR*math.Cos(rad)
+		ny := cy + ringR*math.Sin(rad)
+
+		// Spoke from hub to node
+		dc.DrawLine(hubX, hubY, nx, ny)
+		dc.Stroke()
+
+		// Node dot
+		dc.DrawCircle(nx, ny, nodeR)
+		dc.Fill()
+	}
+
+	// Hub dot (larger)
+	dc.DrawCircle(hubX, hubY, hubR)
+	dc.Fill()
+}
+
+// ─── Metal Rim ────────────────────────────────────────────────────────────────
+
+func drawRim(dc *gg.Context, cx, cy, outerR, rimW, s float64) {
+	// Drop shadow
+	dc.DrawCircle(cx+s*0.005, cy+s*0.008, outerR+s*0.005)
+	dc.SetColor(color.RGBA{10, 8, 5, 120})
+	dc.Fill()
+
+	// Outer dark edge
+	dc.DrawCircle(cx, cy, outerR)
+	dc.SetColor(color.RGBA{38, 32, 25, 255})
+	dc.Fill()
+
+	// Rim body (iron)
+	dc.DrawCircle(cx, cy, outerR-outerR*0.02)
+	dc.SetColor(color.RGBA{72, 62, 50, 255})
+	dc.Fill()
+
+	// Upper-left highlight arc (light source)
+	dc.SetLineWidth(rimW * 0.35)
+	dc.SetLineCap(gg.LineCapRound)
+	dc.SetColor(color.RGBA{105, 95, 78, 220})
+	dc.DrawArc(cx, cy, outerR-rimW*0.5, degToRad(200), degToRad(320))
+	dc.Stroke()
+
+	// Subtle bottom shadow arc
+	dc.SetColor(color.RGBA{30, 25, 18, 150})
+	dc.SetLineWidth(rimW * 0.25)
+	dc.DrawArc(cx, cy, outerR-rimW*0.5, degToRad(30), degToRad(150))
+	dc.Stroke()
+
+	// Inner edge (dark groove where rim meets wood)
+	innerEdgeR := outerR - rimW
+	dc.SetLineWidth(math.Max(1, s*0.012))
+	dc.SetColor(color.RGBA{28, 22, 15, 255})
+	dc.DrawCircle(cx, cy, innerEdgeR)
+	dc.Stroke()
+}
+
+func drawRivets(dc *gg.Context, cx, cy, r, s float64, count int) {
+	rivetR := math.Max(1.0, 1.6*s/64)
+
+	for i := 0; i < count; i++ {
+		a := float64(i)*2*math.Pi/float64(count) + 0.15 // slight rotation offset
+		rx := cx + r*math.Cos(a)
+		ry := cy + r*math.Sin(a)
+
+		// Rivet shadow
+		dc.DrawCircle(rx+rivetR*0.15, ry+rivetR*0.2, rivetR)
+		dc.SetColor(color.RGBA{25, 20, 15, 180})
+		dc.Fill()
+
+		// Rivet body
+		dc.DrawCircle(rx, ry, rivetR)
+		dc.SetColor(color.RGBA{90, 80, 68, 255})
+		dc.Fill()
+
+		// Rivet highlight
+		if s >= 48 {
+			dc.DrawCircle(rx-rivetR*0.25, ry-rivetR*0.3, rivetR*0.4)
+			dc.SetColor(color.RGBA{145, 135, 115, 255})
+			dc.Fill()
+		}
+	}
+}
+
+// ─── Blend Helpers ────────────────────────────────────────────────────────────
+
+func darkenBlend(wood, paint color.RGBA) color.RGBA {
+	return color.RGBA{
+		R: minU8(wood.R, paint.R),
+		G: minU8(wood.G, paint.G),
+		B: minU8(wood.B, paint.B),
+		A: wood.A,
+	}
+}
+
+func lerpColor(a, b color.RGBA, t float64) color.RGBA {
+	return color.RGBA{
+		R: uint8(float64(a.R)*(1-t) + float64(b.R)*t),
+		G: uint8(float64(a.G)*(1-t) + float64(b.G)*t),
+		B: uint8(float64(a.B)*(1-t) + float64(b.B)*t),
+		A: uint8(float64(a.A)*(1-t) + float64(b.A)*t),
+	}
+}
+
+func minU8(a, b uint8) uint8 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func degToRad(d float64) float64 { return d * math.Pi / 180 }
+
+// ─── Image Helpers ────────────────────────────────────────────────────────────
+
+func cropRect(src image.Image, x1, y1, x2, y2 int) image.Image {
+	r := image.Rect(x1, y1, x2, y2).Intersect(src.Bounds())
+	dst := image.NewRGBA(image.Rect(0, 0, r.Dx(), r.Dy()))
+	draw.Draw(dst, dst.Bounds(), src, r.Min, draw.Src)
+	return dst
+}
+
+func scaleImage(src image.Image, w, h int) image.Image {
+	dst := image.NewRGBA(image.Rect(0, 0, w, h))
+	xdraw.CatmullRom.Scale(dst, dst.Bounds(), src, src.Bounds(), xdraw.Over, nil)
+	return dst
+}
+
+func loadPNG(path string) (image.Image, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return png.Decode(f)
+}
+
+func savePNG(img image.Image, path string) []byte {
+	var buf bytes.Buffer
+	png.Encode(&buf, img)
+	os.WriteFile(path, buf.Bytes(), 0644)
+	return buf.Bytes()
+}
+
+// ─── Multi-size ICO ───────────────────────────────────────────────────────────
+
+func writeMultiICO(path string, pngs map[int][]byte, sizes []int) {
 	type entry struct {
 		w, h int
 		data []byte
 	}
-	entries := make([]entry, 0, count)
+	var entries []entry
 	for _, sz := range sizes {
-		data, ok := pngs[sz]
-		if !ok {
-			continue
+		if d, ok := pngs[sz]; ok {
+			entries = append(entries, entry{sz, sz, d})
 		}
-		entries = append(entries, entry{sz, sz, data})
 	}
 
-	// Write ICONDIRENTRY records
+	const headerSize = 6
+	const dirEntrySize = 16
+
+	buf := new(bytes.Buffer)
+	binary.Write(buf, binary.LittleEndian, uint16(0))
+	binary.Write(buf, binary.LittleEndian, uint16(1))
+	binary.Write(buf, binary.LittleEndian, uint16(len(entries)))
+
+	offset := headerSize + dirEntrySize*len(entries)
 	for _, e := range entries {
-		w := byte(e.w)
+		w, h := byte(e.w), byte(e.h)
 		if e.w >= 256 {
 			w = 0
 		}
-		h := byte(e.h)
 		if e.h >= 256 {
 			h = 0
 		}
 		buf.WriteByte(w)
 		buf.WriteByte(h)
-		buf.WriteByte(0)                                              // ColorCount
-		buf.WriteByte(0)                                              // Reserved
-		binary.Write(buf, binary.LittleEndian, uint16(1))             // Planes
-		binary.Write(buf, binary.LittleEndian, uint16(32))            // BitCount
-		binary.Write(buf, binary.LittleEndian, uint32(len(e.data)))   // BytesInRes
-		binary.Write(buf, binary.LittleEndian, uint32(offset))        // ImageOffset
+		buf.WriteByte(0)
+		buf.WriteByte(0)
+		binary.Write(buf, binary.LittleEndian, uint16(1))
+		binary.Write(buf, binary.LittleEndian, uint16(32))
+		binary.Write(buf, binary.LittleEndian, uint32(len(e.data)))
+		binary.Write(buf, binary.LittleEndian, uint32(offset))
 		offset += len(e.data)
 	}
-
-	// Write image data
 	for _, e := range entries {
 		buf.Write(e.data)
 	}
 
-	return buf.Bytes()
+	os.WriteFile(path, buf.Bytes(), 0644)
 }
 
-func generatePreview(path string) {
-	states := []struct {
-		s    icons.State
-		name string
-	}{
-		{icons.StateIdle, "Idle"},
-		{icons.StateSyncing, "Syncing"},
-		{icons.StatePaused, "Paused"},
-		{icons.StateError, "Error"},
-		{icons.StateDisconnected, "Disconnected"},
-	}
+// ─── Preview Sheet ────────────────────────────────────────────────────────────
 
+func generatePreview(wood image.Image, path string) {
 	sz := 128
 	pad := 20
-	w := len(states)*(sz+pad) + pad
-	h := sz + pad*2 + 20
+	w := len(stateColors)*(sz+pad) + pad
+	h := sz + pad*2 + 24
 
 	dc := gg.NewContext(w, h)
 	dc.SetHexColor("#1a1a2e")
 	dc.DrawRectangle(0, 0, float64(w), float64(h))
 	dc.Fill()
 
-	for i, st := range states {
-		// Render at 128px
-		data, err := icons.RenderPNG(st.s, sz)
-		if err != nil {
-			continue
-		}
-		img, err := png.Decode(bytes.NewReader(data))
-		if err != nil {
-			continue
-		}
+	for i, st := range stateColors {
+		img := renderShield(wood, st.color, sz)
 		x := pad + i*(sz+pad)
 		dc.DrawImage(img, x, pad)
-
-		// Label
 		dc.SetHexColor("#cccccc")
-		dc.DrawStringAnchored(st.name, float64(x)+float64(sz)/2, float64(pad+sz+12), 0.5, 0.5)
+		dc.DrawStringAnchored(st.name, float64(x)+float64(sz)/2, float64(pad+sz+14), 0.5, 0.5)
 	}
 
 	dc.SavePNG(path)
-	fmt.Printf("  %s\n", path)
 }