Question

I’m trying to figure out how to output hOCR using Tesseract. Documentation is limited, so I am looking into the code. I found this in the main() function:

bool output_hocr = tessedit_create_hocr;
outfile = argv[2];
outfile += output_hocr ? ".html" : tessedit_create_boxfile ? ".box" : ".txt";

A typical command for Tesseract is this: tesseract input.tif output_file.txt (the output file will be appended with another .txt in this example). main()’s signature is int main(int argc, char **argv).

What exactly is the code snippet doing?

Answer 1

It’s generating the output filename.

bool output_hocr = tessedit_create_hocr;

Saves the tessedit_create_hocr flag in a locally scoped variable.

outfile = argv[2];

Initializes the outfile variable with the base filename from the command line. Something like “Scann0000.tif”.

outfile += output_hocr ? ".html" : tessedit_create_boxfile ? ".box" : ".txt";

Appends the appropriate extension based on flags. Could be re-written as

if( ouput_hocr )
    outfile += ".html";
else if( tessedit_create_boxfile )
    outfile += ".box";
else
    outfile += ".txt";