update at 2026-02-08 18:28:39

miniprogram/workers/svg-generator/index.js

@@ -0,0 +1,105 @@
+const opentype = require('./vendor/opentype.js')
+const { generateSvgFromFont } = require('./svg-builder')
+
+const MAX_FONT_CACHE = 4
+const fontCache = new Map()
+
+function touchCache(key, value) {
+  if (fontCache.has(key)) {
+    fontCache.delete(key)
+  }
+  fontCache.set(key, value)
+
+  while (fontCache.size > MAX_FONT_CACHE) {
+    const firstKey = fontCache.keys().next().value
+    fontCache.delete(firstKey)
+  }
+}
+
+function sendResult(requestId, success, data, error) {
+  worker.postMessage({
+    requestId,
+    success,
+    data,
+    error,
+  })
+}
+
+function handleLoadFont(requestId, payload) {
+  const { fontId, fontBuffer } = payload || {}
+  if (!fontId || !fontBuffer) {
+    throw new Error('加载字体参数无效')
+  }
+
+  const font = opentype.parse(fontBuffer)
+  touchCache(fontId, {
+    font,
+    loadedAt: Date.now(),
+  })
+
+  return { fontId }
+}
+
+function handleGenerateSvg(payload) {
+  const {
+    fontId,
+    text,
+    fontSize,
+    fillColor,
+    letterSpacing,
+    maxCharsPerLine,
+  } = payload || {}
+
+  if (!fontId) {
+    throw new Error('缺少 fontId')
+  }
+
+  const cached = fontCache.get(fontId)
+  if (!cached || !cached.font) {
+    throw new Error('字体未加载，请先加载字体')
+  }
+
+  touchCache(fontId, cached)
+
+  return generateSvgFromFont({
+    text,
+    font: cached.font,
+    fontSize,
+    fillColor,
+    letterSpacing,
+    maxCharsPerLine,
+  })
+}
+
+worker.onMessage((message) => {
+  const { requestId, type, payload } = message || {}
+
+  try {
+    if (!requestId) {
+      throw new Error('缺少 requestId')
+    }
+
+    if (type === 'load-font') {
+      const data = handleLoadFont(requestId, payload)
+      sendResult(requestId, true, data)
+      return
+    }
+
+    if (type === 'generate-svg') {
+      const data = handleGenerateSvg(payload)
+      sendResult(requestId, true, data)
+      return
+    }
+
+    if (type === 'clear-cache') {
+      fontCache.clear()
+      sendResult(requestId, true, { ok: true })
+      return
+    }
+
+    throw new Error(`未知的任务类型: ${type}`)
+  } catch (error) {
+    const messageText = error && error.message ? error.message : String(error)
+    sendResult(requestId, false, null, messageText)
+  }
+})