SECTiff Class

class SECTiff: public SECImage

SECTiff is a SECImage derived class which supports the TIFF (Tagged Image File Format) released by Aldus Corporation and commonly used in scanning and desktop publishing applications. SECTiff is based on the version 6.0 of the TIFF specification.

Defined in: SECTIFF.H

Note: The TIFF library has been upgraded from version 3.3 to 4.2.

Comments

The TIFF file format supports image resolutions from 1 bit per pixel images to 24 bits per pixel images. Compression schemes which can be used in TIFF can include

·Uncompressed
·RLE (run length encoded)
·CCITT Group 3 and 4
·LZW (see discussion below)
·JPEG (see discussion below)

Currently SECTiff supports uncompressed, RLE and (optionally) LZW compression. Although version 6 specifies JPEG compression support, the current specification of JPEG support is actually being redesigned, and many caution against the use of supporting JPEG compression. An excellent discussion of the issues of JPEG support can be found in the text "Encyclopedia of Graphic File Formats" published by O’Reilly & Associates, Inc. For this reason, SECTiff does not currently support JPEG compression in TIFF files.

Another issue for TIFF users concerns the use of LZW compression. Similar to GIF files, LZW compression uses a compression scheme patented by Unisys. Users wishing to support use of TIFF images using LZW compression must license the technology from Unisys (see  SECGif for full details). By default, SECTiff disables LZW support. If you wish to enable LZW support, compile SECTiff with the SEC_TIFF_LZW_SUPPORTED value #defined in the application project.

See the IMAGETST samples in the \SAMPLES\TOOLKIT\STANDARD\IMAGETST directory for a demonstration of this class.

See Also

SECImage  SECGif