In This Topic ▼

LFile::EnumTagsCallBack

#include "ltwrappr.h"

virtual L_INT LFile::EnumTagsCallBack(uTag, uType, uCount)

L_UINT16 uTag;

tag to identify the data in the TIFF file

L_UINT16 uType;

tag data type

L_UINT32 uCount;

number of values

The LFile::EnumTags function will call this callback for each tag present on the page.

Parameter Description
uTag Tag to identify the data in the TIFF file. This may be any tag specified in LFileSettings::SetTag, or any other tag added by the TIFF filter when saving the file. For example, all of the TIFF comments would generate a particular TIFF tag.
uType Tagged data type. Valid values are:
Value Meaning
TAG_BYTE [1] Byte.
TAG_ASCII [2] Byte in the range of 0 to 255.
TAG_SBYTE [6] Byte used as signed number in the range of -128 to +127.
TAG_UNDEFINED [7] Byte, with application-defined usage.
TAG_SHORT [3] Two bytes, unsigned.
TAG_SSHORT [8] Two bytes, signed.
TAG_LONG [4] Four bytes, unsigned.
TAG_SLONG [9] Four bytes, signed.
TAG_RATIONAL [5] Eight bytes, used as a pair of unsigned long integers, where the first number is the numerator and the second is the denominator of a fraction.
TAG_SRATIONAL [10] Eight bytes, used as a pair of signed long integers, where the first number is the numerator and the second is the denominator of a fraction.
TAG_FLOAT [11] Four bytes used as a floating point number.
TAG_DOUBLE [12] Eight bytes used as a double-precision floating point number.
TAG_IFD [13] 32-bit IFD offset.
TAG_LONG8 [16] Unsigned 64-bit integer (valid only for BigTIFF formats).
TAG_SLONG8 [17] Signed 64-bit integer (valid only for BigTIFF formats).
TAG_IFD8 [18] 64-bit IFD offset (valid only for BigTIFF formats).
uCount Number of elements of type uType. Note that this is not the same as the number of bytes. For example, if uCount is 10 and uType is TAG_LONG, you will need 10 x 4 = 40 bytes to read the tag data.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

The LFile::EnumTags function calls this callback for each tag in the page. For more information, refer to LFile::EnumTags.

Do not attempt to use the LFile::DeleteTag function to delete tags from inside an LFile::EnumTagsCallback callback function. If you want to delete tags that you enumerate, use LFile::EnumTagsCallback to add the tags to a list. Upon returning from LFile::EnumTags, you can delete all the tags from the list.

Platforms

Win32, x64.

Help Version 21.0.2020.8.25
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.

LEADTOOLS Raster Imaging C++ Class Library Help