I wonder how Bar Code and QR Code (even character) are recognized without capturing it.I have seen in many app, when we keep our device above any of these (QR/Bar Code), the app automatically recognize it and starts processing. Is there any scanning mechanism used for this? How this can be achieved? What are mechanism involving in this?
Thanks in advance.
1) The phone camera will be launched by the library it will autofocus and scans until it finds the decoded info from the image displayed by camera
2) The info will be parsed by the library and it will give you the result.
the decoded info is "the bar code which has a information decoded in it"
Example for QRCode: The data is present as square
for barcode: the data is present as vertical lines
The library has all the logics for detecting the type of code and decoding as per the format. Please read more the QrCode/Bar code libraries docs or implement it and learn