fix: gif-player 真实播放(observer+画布重试) + 帧延迟单位修正(1/100s→ms)

miniprogram/components/gif-player/gif-player.js

@@ -4,8 +4,15 @@ const { GifReader } = require('../../utils/vendor/omggif.js');
 
 Component({
   properties: {
-    // GIF 地址（通常是 ex.gifUrl，原始 180px 动图）
-    src: { type: String, value: '' }
+    // GIF 地址（通常是 ex.gifUrl，超分后的 720px 动图）
+    src: {
+      type: String,
+      value: '',
+      // src 可能在组件 attached 之后才由父页面异步设上，用 observer 兜底重新加载
+      observer(value) {
+        if (value) this._load();
+      }
+    }
   },
   data: {
     failed: false
@@ -14,24 +21,37 @@ Component({
     attached() {
       this._aborted = false;
       this._timer = null;
+      this._reader = null;
+      this._ctx = null;
+      this._rgba = null;
+      this._frame = 0;
       if (this.data.src) this._load();
     },
     detached() {
-      this._aborted = true;
-      if (this._timer) { clearTimeout(this._timer); this._timer = null; }
+      this._abort();
     }
   },
   methods: {
+    _abort() {
+      this._aborted = true;
+      if (this._timer) { clearTimeout(this._timer); this._timer = null; }
+    },
+    // 下载 GIF 二进制并构造解码器（解耦于画布，便于画布未就绪时重试渲染）
     _load() {
       const src = this.data.src;
-      if (!src) return;
+      if (!src || this._aborted) return;
+      // 防重复：attached 与 observer 可能都触发；同一 src 只加载一次
+      if (this._loadedSrc === src && this._reader) return;
+      this._loadedSrc = src;
+      this._abort(); // 清掉上一次可能的循环定时器
       wx.request({
         url: src,
         responseType: 'arraybuffer',
         success: (res) => {
           if (this._aborted) return;
           try {
-            this._play(res.data);
+            this._reader = new GifReader(new Uint8Array(res.data));
+            this._start();
           } catch (e) {
             console.error('[gif-player] decode fail', e);
             this.setData({ failed: true });
@@ -42,42 +62,51 @@ Component({
         }
       });
     },
-    _play(buffer) {
-      const bytes = buffer instanceof ArrayBuffer ? new Uint8Array(buffer) : new Uint8Array(buffer);
-      const reader = new GifReader(bytes);
-      const numFrames = reader.numFrames();
-      if (!numFrames) { this.setData({ failed: true }); return; }
-      const w = reader.width;
-      const h = reader.height;
+    // 等待 Canvas 2D 节点就绪（自定义组件里 attached 时可能还没布局好，最多重试 10 次）
+    _start(attempt = 0) {
+      if (this._aborted || !this._reader) return;
       const q = wx.createSelectorQuery().in(this);
       q.select('#gifCanvas').fields({ node: true, size: true }).exec((rs) => {
-        if (this._aborted || !rs || !rs[0] || !rs[0].node) return;
+        if (this._aborted) return;
+        if (!rs || !rs[0] || !rs[0].node) {
+          if (attempt < 10) setTimeout(() => this._start(attempt + 1), 60);
+          return;
+        }
         const canvas = rs[0].node;
         const ctx = canvas.getContext('2d');
-        // 画布内部分辨率=GIF 原始分辨率；CSS 负责缩放到容器
+        const w = this._reader.width;
+        const h = this._reader.height;
+        // 画布内部分辨率 = GIF 原始分辨率（已超分到 720）；CSS 负责缩放到容器
         canvas.width = w;
         canvas.height = h;
-        const rgba = new Uint8ClampedArray(w * h * 4);
-        let frame = 0;
-        const render = () => {
-          if (this._aborted) return;
-          try {
-            // decodeAndBlitFrameRGBA 会按 GIF 的 disposal 规则在 rgba 上累积绘制
-            reader.decodeAndBlitFrameRGBA(frame, rgba);
-            const img = ctx.createImageData(w, h);
-            img.data.set(rgba);
-            ctx.putImageData(img, 0, 0);
-          } catch (e) {
-            console.error('[gif-player] frame fail', e);
-            return;
-          }
-          const info = reader.frameInfo(frame);
-          const delay = info && info.delay ? info.delay : 100;
-          frame = (frame + 1) % numFrames;
-          this._timer = setTimeout(render, Math.max(16, delay));
-        };
-        render();
+        this._ctx = ctx;
+        this._rgba = new Uint8ClampedArray(w * h * 4);
+        this._frame = 0;
+        this._render();
       });
+    },
+    _render() {
+      if (this._aborted || !this._reader || !this._ctx) return;
+      const r = this._reader;
+      const n = r.numFrames();
+      if (!n) { this.setData({ failed: true }); return; }
+      try {
+        // decodeAndBlitFrameRGBA 按 GIF 的 disposal 规则在 rgba 上累积绘制
+        r.decodeAndBlitFrameRGBA(this._frame, this._rgba);
+        const img = this._ctx.createImageData(r.width, r.height);
+        img.data.set(this._rgba);
+        this._ctx.putImageData(img, 0, 0);
+      } catch (e) {
+        console.error('[gif-player] frame fail', e);
+        this.setData({ failed: true });
+        return;
+      }
+      const info = r.frameInfo(this._frame);
+      // omggif 的 delay 单位是 1/100 秒，需 ×10 转毫秒；缺失时给 100ms
+      const delay = (info && info.delay) ? info.delay * 10 : 100;
+      this._frame = (this._frame + 1) % n;
+      // 单帧 GIF 只画一次；多帧才循环。最小 40ms 避免极端快帧
+      if (n > 1) this._timer = setTimeout(() => this._render(), Math.max(40, delay));
     }
   }
 });

miniprogram/components/gif-player/gif-player.wxml

@@ -1,3 +1,3 @@
 <view class="gif-player">
-  <canvas type="2d" id="gifCanvas" class="canvas"></canvas>
+  <canvas wx:if="{{!failed}}" type="2d" id="gifCanvas" class="canvas"></canvas>
 </view>