如何避免预览流产生畸变
===========

使用下列代码获取设备支持的宽和高，然后根据手机屏幕的宽高设置最合适的预览流分辨率，并使surface和XComponent的宽高一致。

_//The aspect ratio of the preview stream and the video output stream resolution should be consistent_
let previewProfilesArray: Array<camera.Profile> = cameraOutputCap.previewProfiles;

let position: number = 0;
if (previewProfilesArray != null) {
  previewProfilesArray.forEach((value: camera.Profile,index: number) => {
   _ // View supported preview sizes_
    console.info(TAG,
      \`支持的预览尺寸: \[${value.size.width},${value.size.height},${value.size.width / value.size.height}\]\`);
    if (value.size.width === 2592 && value.size.height === 1200) {
      position = index;
    }
  })
} else {
  console.error(TAG,"createOutput photoProfilesArray == null || undefined");
}

let photoProfilesArray: Array<camera.Profile> = cameraOutputCap.photoProfiles;
if (!photoProfilesArray) {
  console.error(TAG,"createOutput photoProfilesArray == null || undefined");
}

this.xComponentWidth = previewProfilesArray\[position\].size.width;
this.xComponentHeight = previewProfilesArray\[position\].size.height;

this.mXComponentController.setXComponentSurfaceSize({
  surfaceWidth: this.xComponentWidth,
  surfaceHeight: this.xComponentHeight
});
_// Create a preview output stream, where the parameter surfaceId refers to the XComponent component mentioned earlier,_
_// and the preview stream is the surface provided by the XComponent component_
try {
  previewOutput = cameraManager.createPreviewOutput(previewProfilesArray\[position\],surfaceId);
} catch (error) {
  let err = error as BusinessError;
  console.error(TAG,\`Failed to create the PreviewOutput instance. error code: ${err.code}\`);
}
if (previewOutput === undefined) {
  return;
}

_// Monitor preview output error message_
previewOutput.on('error',(error: BusinessError) => {
  console.error(TAG,\`Preview output error code: ${error.code}\`);
});

_// Create an ImageReceiver object and set photo parameters:_
_// The resolution size is set based on the current device's supported photo resolution size obtained from the previous photoProfilesArray_
let size: image.Size = {
  height: 1200,
  width: 2592
}
let imageReceiver: image.ImageReceiver = image.createImageReceiver(size,4,8);