IG_fltr_compressionlist

This function returns the list of compressions available for saving the specified image to a particular file format. This is an obsolete function, see remarks.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_fltr_compressionlist_get( LPAT_DIB lpDIB, AT_MODE nFormatID, LPAT_MODE lpComprList, UINT nCListSize, LPUINT lpnCListCount );

Arguments:

Name	Type	Description
lpDIB	LPAT_DIB	Pointer to the AT_DIB structure that contains image parameters. If NULL, then this function returns all possible compressions.
nFormatID	AT_MODE	File format identifier. See enumIGFormats for possible values.
lpComprList	LPAT_MODE	Pointer to the array to return the list of compression constants to. See enumIGCompressions for possible values. Set to NULL if you only need to obtain the number of available compressions.
nCListSize	UINT	Size of the lpCompList array.
lpnCListCount	LPUINT	Pointer to a variable which will receive the actual number of compression constants.

Return Value:

Returns 0 if successful. Otherwise, returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:

Indexed RGB - 1, 4, 8 bpp;
Grayscale - 9...16 bpp;
RGB - 24 bpp;
CMYK - 32 bpp.

Sample:

None

Example:

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AT_ERRCOUNT nErrCount; // Number of errors on stack HIGEAR hIGear; // Handle of image UINT nCount, nActual; // Number of compressions LPAT_MODE lpCompList; // List of compressions // Load the image nErrCount = IG_load_file("picture.tif", &hIGear); if( nErrCount == 0 ) { AT_DIB atDib; AT_DIMENSION nWidth, nHeight; UINT nBitsPerPixel; // Get image info nErrCount = IG_image_dimensions_get(hIGear, &nWidth, &nHeight, &nBitsPerPixel); // Fill in AT_DIB structure memset(&atDib, 0, sizeof(AT_DIB)); atDib.biSize = sizeof(AT_DIB); atDib.biWidth = nWidth; atDib.biHeight = nHeight; atDib.biPlanes = 1; atDib.biBitCount = nBitsPerPixel; // Get compression count nErrCount = IG_fltr_compressionlist_get(&atDib, IG_FORMAT_TIF, NULL, 0, &nCount); // Allocate memory for compressions lpCompList = (LPAT_MODE) malloc(nCount * sizeof(AT_MODE)); // Get list of compressions that can be used when // saving the given image into TIFF format nErrCount = IG_fltr_compressionlist_get(&atDib, IG_FORMAT_TIF, lpCompList, nCount, &nActual); // ... // Delete memory free(lpCompList); // Delete the image IG_image_delete(hIGear); }

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AT_ERRCOUNT nErrCount;  // Number of errors on stack
HIGEAR hIGear;          // Handle of image
UINT nCount, nActual;   // Number of compressions
LPAT_MODE lpCompList;   // List of compressions

// Load the image
nErrCount = IG_load_file("picture.tif", &hIGear);
if( nErrCount == 0 ) 
{
    AT_DIB atDib;
    AT_DIMENSION nWidth, nHeight;
    UINT nBitsPerPixel;
    // Get image info
    nErrCount = IG_image_dimensions_get(hIGear, &nWidth, &nHeight, &nBitsPerPixel);
    // Fill in AT_DIB structure
    memset(&atDib, 0, sizeof(AT_DIB));
    atDib.biSize = sizeof(AT_DIB);
    atDib.biWidth = nWidth;
    atDib.biHeight = nHeight;
    atDib.biPlanes = 1;
    atDib.biBitCount = nBitsPerPixel;
    
    // Get compression count 
    nErrCount = IG_fltr_compressionlist_get(&atDib, 
        IG_FORMAT_TIF, NULL, 0, &nCount);
    // Allocate memory for compressions
    lpCompList = (LPAT_MODE) malloc(nCount * sizeof(AT_MODE));
    // Get list of compressions that can be used when  
    // saving the given image into TIFF format
    nErrCount = IG_fltr_compressionlist_get(&atDib, 
        IG_FORMAT_TIF, lpCompList, nCount, &nActual);

    // ...

    // Delete memory
    free(lpCompList);
    // Delete the image
    IG_image_delete(hIGear);
}

Remarks:

This function is only kept for backward compatibility reasons. Please use IG_fltr_compressionlist_get_ex instead.

See also the section Using Format Filters API for Image Saving.