Method replaceFrame

lib/webp.js:395–471

(path, frame)

  }

  replaceFrame(path, frame) {
    var _this3 = this;

    return _asyncToGenerator(function* () {
      if (!_this3.hasAnim) {
        throw new Error("WebP isn't animated");
      }

      if (frame < 0 || frame >= _this3.frameCount) {
        throw new Error(
          `Frame index ${frame} out of bounds (0<=index<${_this3.frameCount})`
        );
      }

      let r = new Image();
      yield r.load(path);

      switch (r.type) {
        case constants.TYPE_LOSSY:
        case constants.TYPE_LOSSLESS:
          break;

        case constants.TYPE_EXTENDED:
          if (r.hasAnim) {
            throw new Error("Merging animations not currently supported");
          }

          break;

        default:
          throw new Error("Unknown WebP type");
      }

      switch (_this3.anim.frames[frame].type) {
        case constants.TYPE_LOSSY:
          if (_this3.anim.frames[frame].vp8.alpha) {
            delete _this3.anim.frames[frame].alph;
          }

          delete _this3.anim.frames[frame].vp8;
          break;

        case constants.TYPE_LOSSLESS:
          delete _this3.anim.frames[frame].vp8l;
          break;

        default:
          throw new Error("Unknown frame type");
      }

      switch (r.type) {
        case constants.TYPE_LOSSY:
          _this3.anim.frames[frame].vp8 = r.data.vp8;
          break;

        case constants.TYPE_LOSSLESS:
          _this3.anim.frames[frame].vp8l = r.data.vp8l;
          break;