Add social preview image and Open Graph tags

index.html

@@ -7,6 +7,20 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
     <meta name="theme-color" content="#f97316" />
     <meta name="description" content="Analyze orienteering maps — import GPX tracks, draw routes, and export annotated maps." />
+    <link rel="canonical" href="https://oanalysis.com/" />
+    <meta property="og:type" content="website" />
+    <meta property="og:site_name" content="O-Analysis" />
+    <meta property="og:title" content="O-Analysis — orienteering map analysis" />
+    <meta property="og:description" content="Analyze orienteering maps — import GPX tracks, draw routes, and export annotated maps." />
+    <meta property="og:url" content="https://oanalysis.com/" />
+    <meta property="og:image" content="https://oanalysis.com/og-image.png" />
+    <meta property="og:image:width" content="1200" />
+    <meta property="og:image:height" content="630" />
+    <meta property="og:image:alt" content="A map with GPX tracks and numbered control markers, shown in O-Analysis" />
+    <meta name="twitter:card" content="summary_large_image" />
+    <meta name="twitter:title" content="O-Analysis — orienteering map analysis" />
+    <meta name="twitter:description" content="Analyze orienteering maps — import GPX tracks, draw routes, and export annotated maps." />
+    <meta name="twitter:image" content="https://oanalysis.com/og-image.png" />
     <meta name="application-name" content="O-Analysis" />
     <meta name="apple-mobile-web-app-capable" content="yes" />
     <meta name="apple-mobile-web-app-title" content="O-Analysis" />

package.json

@@ -6,6 +6,7 @@
   "scripts": {
     "dev": "vite",
     "generate-icons": "node scripts/generate-pwa-icons.mjs",
+    "generate-og-image": "bun run scripts/generate-og-image.mjs",
     "build": "bun run generate-icons && tsc -b && vite build",
     "lint": "oxlint",
     "test": "vitest run",

scripts/generate-og-image.mjs

@@ -0,0 +1,82 @@
+import { readFileSync, writeFileSync } from 'node:fs'
+import { dirname, join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import sharp from 'sharp'
+
+const root = join(dirname(fileURLToPath(import.meta.url)), '..')
+const WIDTH = 1200
+const HEIGHT = 630
+
+// The social card shows a real map from the bundled sample project
+const sample = JSON.parse(readFileSync(join(root, 'public/sample.anal'), 'utf8'))
+const [, mapBase64] = sample.mapImage.src.split(',')
+const mapPng = await sharp(Buffer.from(mapBase64, 'base64'))
+  .resize({ width: 960, withoutEnlargement: true })
+  .jpeg({ quality: 88 })
+  .toBuffer()
+const mapMeta = await sharp(mapPng).metadata()
+
+const CARD_W = 430
+const CARD_H = Math.round((CARD_W * mapMeta.height) / mapMeta.width)
+const card = { x: 732, y: (HEIGHT - CARD_H) / 2 - 6 }
+const cardCentre = { x: card.x + CARD_W / 2, y: card.y + CARD_H / 2 }
+const toCardPx = (fx, fy) => ({ x: card.x + fx * CARD_W, y: card.y + fy * CARD_H })
+
+// Orange control markers placed over the map, in fractions of the card size
+const markers = [
+  { label: 'A', fx: 0.3, fy: 0.42 },
+  { label: 'B', fx: 0.52, fy: 0.58 },
+  { label: 'C', fx: 0.74, fy: 0.36 },
+]
+
+const logo = readFileSync(join(root, 'public/favicon.svg')).toString('base64')
+const mapDataUrl = `data:image/jpeg;base64,${mapPng.toString('base64')}`
+
+const markerSvg = markers
+  .map(({ label, fx, fy }) => {
+    const p = toCardPx(fx, fy)
+    return `
+      <circle cx="${p.x}" cy="${p.y}" r="17" fill="#f97316" stroke="#fff" stroke-width="4"/>
+      <text x="${p.x}" y="${p.y + 7}" text-anchor="middle" font-family="Helvetica, Arial, sans-serif" font-size="20" font-weight="700" fill="#fff">${label}</text>`
+  })
+  .join('')
+
+const svg = `
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="${WIDTH}" height="${HEIGHT}" viewBox="0 0 ${WIDTH} ${HEIGHT}">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#16141b"/>
+      <stop offset="1" stop-color="#262030"/>
+    </linearGradient>
+    <radialGradient id="glow" cx="0.85" cy="0.15" r="0.6">
+      <stop offset="0" stop-color="#f97316" stop-opacity="0.35"/>
+      <stop offset="1" stop-color="#f97316" stop-opacity="0"/>
+    </radialGradient>
+    <filter id="shadow" x="-20%" y="-20%" width="140%" height="150%">
+      <feGaussianBlur stdDeviation="18"/>
+    </filter>
+  </defs>
+
+  <rect width="${WIDTH}" height="${HEIGHT}" fill="url(#bg)"/>
+  <rect width="${WIDTH}" height="${HEIGHT}" fill="url(#glow)"/>
+
+  <image href="data:image/svg+xml;base64,${logo}" x="72" y="92" width="92" height="92"/>
+  <text x="72" y="282" font-family="Helvetica, Arial, sans-serif" font-size="88" font-weight="700" fill="#fff7ed" letter-spacing="-2">O-Analysis</text>
+  <text font-family="Helvetica, Arial, sans-serif" font-size="34" fill="#d6d3d1">
+    <tspan x="72" y="340">Analyze and annotate your</tspan>
+    <tspan x="72" y="384">orienteering sessions</tspan>
+  </text>
+
+  <g transform="rotate(-3 ${cardCentre.x} ${cardCentre.y})">
+    <rect x="${card.x + 10}" y="${card.y + 22}" width="${CARD_W}" height="${CARD_H}" rx="18" fill="#000" opacity="0.55" filter="url(#shadow)"/>
+    <rect x="${card.x - 10}" y="${card.y - 10}" width="${CARD_W + 20}" height="${CARD_H + 20}" rx="18" fill="#fff"/>
+    <image href="${mapDataUrl}" x="${card.x}" y="${card.y}" width="${CARD_W}" height="${CARD_H}" preserveAspectRatio="xMidYMid slice"/>
+    ${markerSvg}
+  </g>
+
+  <text x="72" y="578" font-family="Helvetica, Arial, sans-serif" font-size="22" fill="#a8a29e">oanalysis.com</text>
+</svg>`
+
+const png = await sharp(Buffer.from(svg)).png().toBuffer()
+writeFileSync(join(root, 'public/og-image.png'), png)
+console.log(`Generated og-image.png (${WIDTH}x${HEIGHT})`)