JFIF & JFIF Extension Function Reference
The "App 0" segment is often used by the JPEG File Interchange Format (JFIF) information. Sometimes, there is an additional "App 0" segment for the JFIF Extension (JFXX) information.
| Function: | get_JFIF | |
| Description: | Retrieves information from a JPEG File Interchange Format (JFIF) segment and returns it in an array. Uses information supplied by the get_jpeg_header_data function | |
| Parameters: | jpeg_header_data | a JPEG header data array in the same format as from get_jpeg_header_data |
| Returns: | JFIF_data | an array of JFIF data |
| FALSE | if a JFIF segment could not be found | |
| Function: | put_JFIF | |
| Description: | Creates a new JFIF segment from an array of JFIF data in the same format as would be retrieved from get_JFIF, and inserts this segment into the supplied JPEG header array | |
| Parameters: | jpeg_header_data | a JPEG header data array in the same format as from get_jpeg_header_data, into which the new JFIF segment will be put |
| new_JFIF_array | a JFIF information array in the same format as from get_JFIF, to create the new segment | |
| Returns: | jpeg_header_data | the JPEG header data array with the new JFIF segment added |
| Function: | Interpret_JFIF_to_HTML | |
| Description: | Generates html showing the JFIF information contained in a JFIF data array, as retrieved with get_JFIF | |
| Parameters: | JFIF_array | a JFIF data array, as from get_JFIF |
| filename | the name of the JPEG file being processed (used by the script which displays the JFIF thumbnail) | |
| Returns: | output | the HTML string |
| Function: | get_JFXX | |
| Description: | Retrieves information from a JPEG File Interchange Format Extension (JFXX) segment and returns it in an array. Uses information supplied by the get_jpeg_header_data function | |
| Parameters: | jpeg_header_data | a JPEG header data array in the same format as from get_jpeg_header_data |
| Returns: | JFXX_data | an array of JFXX data |
| FALSE | if a JFXX segment could not be found | |
| Function: | put_JFXX | |
| Description: | Creates a new JFXX segment from an array of JFXX data in the same format as would be retrieved from get_JFXX, and inserts this segment into the supplied JPEG header array | |
| Parameters: | jpeg_header_data | a JPEG header data array in the same format as from get_jpeg_header_data, into which the new JFXX segment will be put |
| new_JFXX_array | a JFXX information array in the same format as from get_JFXX, to create the new segment | |
| Returns: | jpeg_header_data | the JPEG header data array with the new JFXX segment added |
| Function: | Interpret_JFXX_to_HTML | |
| Description: | Generates html showing the JFXX thumbnail contained in a JFXX data array, as retrieved with get_JFXX | |
| Parameters: | JFXX_array | a JFXX information array in the same format as from get_JFXX, to create the new segment |
| filename | the name of the JPEG file being processed (used by the script which displays the JFXX thumbnail) | |
| Returns: | output | the Html string |