JPEG comment data

[Dar Scott]

On Monday, September 22, 2003, at 05:34 AM, Rodney Tamblyn wrote:

> Does anyone have an example code snippet of how to access COM 
> (comment) or APP1 chunk information from JPEG images in Revolution?

I have not broken up JPEG, but I have attacked other binary files in 
Revolution.

The file format seems to be defined for additional info, though there 
might be some idiosyncrasies.  Process the file using binaryDecode.  
One approach would be to make a function that takes an image and 
returns, say, an array of values by name.  The name might be based on 
that used in standards.  For fixed position fields, access functions 
might work, but I have found that accessing data with variable length 
fields is easier if the file is preprocessed to break out the 
components.  The only problem is that arrays can currently be only one 
layer deep and line and item lists are needed for the other levels.  In 
most cases that is just fine.  In other cases, data can be burst in 
layers.

Dar Scott

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