2009.12.09 08:11 "Re: [Tiff] Problems with multiple strip G4 to single strip G4 tiff.", by Juergen Buchmueller

On Wed, 9 Dec 2009 02:47:52 -0500

I am 99.9% certain that it is my code that is causing the crash. I should have been clearer on that.

Ok, I thought you had checked that :)

I downloaded GDB and it looks interesting, but it's likely overkill for this problem and likely over my head.

Nah, it's dead simple. Let your program write a coredump (perhaps setting "ulimit -c unlimited" before), then run "gdb path/to/your/program xyz.core" and do a "bt" for backtrace. If you compiled your code with symbols (-g option of gcc) you'll see on which line it was.

I'm not asking that anyone do the work for me. I'm looking for direction (or explanation as to what I'm doing wrong) to the correct way to save the image a single strip, when the original image was multiple strip.

I thought you wanted to do it the other way round? Anyway, here's a code snippet from my libtiff usage, omitting the setting of all the other necessary tags:

/* write a striped image */
rowsperstrip = TIFFDefaultStripSize(hTIFF, fmt->image_length);
if (rowsperstrip > fmt->image_length) {
        rowsperstrip = fmt->image_length;
        LOG(LINFO,(_fun,"clamping to image length: %u\n",
                rowsperstrip));
}

rc = TIFFSetField(hTIFF, TIFFTAG_ROWSPERSTRIP, rowsperstrip); for (y = 0; y < fmt->image_length; y++) {

        tdata_t row = (tdata_t)(tiff->mem.data + y * tiff->stride + x);

        rc = TIFFWriteScanline(hTIFF, row, y, 0);
        if (rc != 1) {
                LOG(LERROR,(_fun,"TIFFWriteScanline(%p,%p,%d,%d) "
                 "failed (%d)\n", tiff, row, y, 0, rc));
                goto abort;
        }
}
...

HTH,

Juergen