IG_load_thumbnail

This function loads a thumbnail from the image located in a memory buffer.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_load_thumbnail_mem( LPVOID lpImage, AT_UINT nSize, LPHIGEAR lphIGear );

Arguments:

Name	Type	Description
lpImage	LPVOID	Pointer to start of the image in memory.
nSize	AT_UINT	Size of image in memory.
lphIGear	LPHIGEAR	Pointer to HIGEAR variable to receive handle.

Return Value:

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

Supported Raster Image Formats:

All pixel formats supported by ImageGear for C and C++.

Example:

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HIGEAR hIGear1 = 0; /* handle ret'd by IG_load_mem / HIGEAR hIGear2 = 0; / ret'd by IG_load_thumbnail_mem / char far lpWhereFile = NULL; /* ptr to image file in mem / AT_UINT nImageSize; / Size of image in memory / AT_ERRCOUNT nErrcount;/ to test for errors / // Open a file and get its size FILE fd; fopen_s(&fd, "picture.bmp", "rb"); if(fd != NULL) { fseek(fd, 0, SEEK_END); nImageSize = (AT_UINT)ftell(fd); fseek(fd, 0, SEEK_SET); // Allocate memory and read the image into the memory buffer lpWhereFile = (char*)malloc(nImageSize); fread(lpWhereFile, 1, nImageSize, fd); // File is no longer needed - close it fclose(fd); } // Load image from the memory nErrcount = IG_load_mem(lpWhereFile, nImageSize, 1, 0, &hIGear1); if ( nErrcount == 0 ) { nErrcount = IG_load_thumbnail_mem(lpWhereFile, nImageSize, &hIGear2); } // delete memory if(lpWhereFile) { free(lpWhereFile); } //... // Destroy images if(IG_image_is_valid(hIGear1)) { IG_image_delete(hIGear1); } if(IG_image_is_valid(hIGear2)) { IG_image_delete(hIGear2); }

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HIGEAR hIGear1 = 0;       /* handle ret'd by IG_load_mem  */
HIGEAR hIGear2 = 0;       /* ret'd by IG_load_thumbnail_mem  */
char far * lpWhereFile = NULL;    /* ptr to image file in mem   */
AT_UINT  nImageSize;   /* Size of image in memory */
AT_ERRCOUNT nErrcount;/* to test for errors         */

// Open a file and get its size
FILE* fd;
fopen_s(&fd, "picture.bmp", "rb");
if(fd != NULL)
{
    fseek(fd, 0, SEEK_END);
    nImageSize = (AT_UINT)ftell(fd);
    fseek(fd, 0, SEEK_SET);
    // Allocate memory and read the image into the memory buffer
    lpWhereFile = (char*)malloc(nImageSize);
    fread(lpWhereFile, 1, nImageSize, fd);
    // File is no longer needed - close it
    fclose(fd);
}
// Load image from the memory
nErrcount = IG_load_mem(lpWhereFile, nImageSize, 1, 0, &hIGear1);
if ( nErrcount == 0 )
{ 
    nErrcount = IG_load_thumbnail_mem(lpWhereFile, nImageSize, &hIGear2); 
}
// delete memory 
if(lpWhereFile)
{
    free(lpWhereFile);
}

//...

// Destroy images
if(IG_image_is_valid(hIGear1))
{
    IG_image_delete(hIGear1);
}
if(IG_image_is_valid(hIGear2))
{
    IG_image_delete(hIGear2);
}

Remarks:

The handle of the resulting image is returned to the HIGEAR variable pointed to by argument lphIGear. See also functions IG_load_thumbnail, and IG_save_thumbnail_set.