LFileSettings::SetComment
#include "ltwrappr.h"
static L_INT LFileSettings::SetComment(uType, pComment, uLength)
L_UINT uType; |
/* type of comment */ |
L_UCHAR * pComment; |
/* pointer to the buffer for the comment field */ |
L_UINT uLength; |
/* size of the buffer that contains the comment field */ |
Specifies a field to be saved as a comment in a file.
Parameter |
Description |
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uType |
The type of comment. Valid values are: |
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Value |
Meaning |
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CMNT_LAST |
Last defined number for comments. To clear all fields, you can use the type constant as a loop counter. The first constant is 0 and the last is CMNT_LAST. |
pComment |
Pointer to the buffer containing the comment field that you want to set. You can pass NULL to clear the current field. |
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uLength |
The size of your buffer that contains the comment field. (If the buffer is actually a single string, this is the string length + 1.) |
Returns
>=0 |
Length of the comment field. |
< 0 |
An error occurred. Refer to Return Codes. |
Comments
Some file formats can contain comments, and some cannot, and each file format has its own set of comment types. When you save a file, the comments, which LEADTOOLS maintains in a global array, are saved in the file. The index into the array (specified using a constant) determines the type of comment, as described in Types of File Comments.
Note: |
When LEADTOOLS saves a TIFF/Exif image that contains comments and tags, the comments and tags will be written first, followed by the image data. This order is not configurable. |
This function works with related functions. For example, consider the following possible sequence:
1. |
Use the LFileSettings::SetComment function to specify any of the comments that you want to save in a file header. |
2. |
Use the LFileSettings::GetComment function to let the user review the comments before they are saved. |
3. |
Save one or more files that you want to include the currently specified comments. You can use any LEADTOOLS function that saves a file. The file format can be any that includes a TIFF header, such as CCITT or TIFF (but not JTIF). |
4. |
Use the LFileSettings::SetComment function with a NULL buffer and 0 length to clear each of the comment fields. You must call the this function once for each specified field. To clear all fields, you can use the type constant as a loop counter. The first constant (specified in the uType parameter) is 0 and the last is CMNT_LAST. |
5. |
Use the LFile::ReadComment function to let the user review the comments that have been saved in a file. |
Note: |
More options are available in the SAVEFILEOPTION structure. |
Required DLLs and Libraries
LTFIL For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application. |
See Also
Example
For an example, refer to LFile::ReadComment.