To do a sweep code software to upload the contents of the scanning frame to the server, my practice is in the flow will scan preview box dug up the images uploaded to the server, now requires uploaded to the server in much higher than the original image pixels, so you have to improve the resolution of the preview flow, but a lot of phone support preview of the highest resolution is only 1920 * 1080, but the iphone is to support high resolution preview, so have the leaders know how to get high resolution preview flow