2002.02.27 02:53 "Must set "ImageWidth" before writing data", by Stephen
Rasku
Thread
2002.02.28 17:56 "Re: Must set "ImageWidth" before writing data", by Stephen Rasku
I am trying to write an encoded strip and I am getting the error message specified in the subject line. I am using v3.5.5.
I looked in the source and this happens if FIELD_IMAGEDIMENSIONS is not set. However, the man page for TIFFSetField doesn't mention this field. In fact, tif_dir.h, refers to this as a "multi-item field". This leads me to believe (possibly incorrectly) that this is set automatically by the TIFF library if you set the correct fields.
I am explicitly setting the following fields:
TIFFTAG_COMPRESSION
TIFFTAG_IMAGEWIDTH
TIFFTAG_ROWSPERSTRIP
TIFFTAG_ROWSPERSTRIP
TIFFTAG_YRESOLUTIONAre there other fields I need to set to get rid of this error message?
Here's the code for a sample program that has the problem:
#include <stdio.h>
#include <stdarg.h>
#include "tiffio.h"
#define OUTFILE "tiffcreate.tif"
#define NUMROWS 10
#define IMAGE_WIDTH 16
#define BYTES_PER_BUF IMAGE_WIDTH/8
unsigned char blackbuf[BYTES_PER_BUF];
unsigned char whitebuf[BYTES_PER_BUF];
void myHandler(const char *module, const char *fmt, va_list ap)
{
fprintf(stderr, "%s: ", module);
fprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}
main(int argc, char *argv[])
{
TIFFSetErrorHandler(myHandler);
do {
TIFF *tif;
int row;
memset(blackbuf, -1, BYTES_PER_BUF);
memset(whitebuf, 0, BYTES_PER_BUF);
if ( !( tif = TIFFOpen(OUTFILE, "w") ) )
{
fprintf(stderr, "%s: Error opening file %s\n", argv[0], OUTFILE);
break;
}
if ( !(TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_CCITTFAX3) &&
TIFFSetField(tif, TIFFTAG_IMAGEWIDTH, (unsigned)IMAGE_WIDTH) &&
TIFFSetField(tif, TIFFTAG_IMAGELENGTH, (unsigned)NUMROWS) &&
TIFFSetField(tif, TIFFTAG_ROWSPERSTRIP, (unsigned)1) ) )
break;
TIFFSetField(tif, TIFFTAG_YRESOLUTION, 196.);
TIFFSetField(tif, TIFFTAG_XRESOLUTION, 204.);
TIFFWriteDirectory(tif);
for (row = 0; row < NUMROWS; ++row)
if ( TIFFWriteEncodedStrip(tif, row, row % 2 ? blackbuf : whitebuf,
IMAGE_WIDTH) == -1) break;
TIFFClose(tif);
} while(0);
}
Stephen Rasku E-mail: stephen@tgivan.com
Senior Software Engineer Web: http://www.pop-star.net/
TGI Technologies