let that = new util.Base64Helper();
let base64 = 'iVBORw0KGgoxxxANSUhEUgAAAB4xxxxtCAMAAACOACuTAAAALVxxxxU03QE02QU48PEs0Q0s2QU42Qk43QE43QU03QU04P043QE43QVA3QU7fFG+6AAAADnRSTlMAu3fuESKPVd1mzESqM0jcJEgAAACOSURBVHjatZBJEsAgCARV3BP5/3Oj3mdIZZlrF9CMs+Jx2sSKE/7FIEMmzYimxxxxykA060xDtKipVelhLYiGRU+6WhJdHai1QK+6X6ZeFXYt9rBEOhzosCaqnfHPtO2TfpV0JXOxgXB/v5t7q0PZ1CN66I2+D3460q/lodkgpdjibeNm/fVtLk4YEK1O5uSkAAAAAElFTkSuQmCC';
let result:Uint8Array = that.decodeSync(base64, util.Type.MIME);
let buf:ArrayBuffer = result.buffer as ArrayBuffer
const imageSourceApi: image.ImageSource = image.createImageSource(buf);
this.pixmap1=await imageSourceApi.createPixelMap()
请参考代码: