IG_load_mem_CB

This function loads an image from a file using user-defined callback functions.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_load_mem_CB_ex( LPVOID lpImage, AT_UINT nSize, UINT nPage, UINT nReserved, LPFNIG_RASTER_SET lpfnRasterSet, LPFNIG_DIB_CREATE_EX lpfnDIBCreateEx, LPVOID lpPrivateData );

Arguments:

lpImage	Pointer to a memory buffer containing the image.
nSize	Size of image in memory.
nPage	Page number to load if this is a multi-page file. Note that page numbers begin at 1, not 0. Set nPage to 1 if this is not a multi-page file.
nReserved	Reserved, should be set to 0 for now.
lpfnRasterSet	Pointer to callback function to be called after each raster line is read. See LPFNIG_RASTER_SET.
lpfnDIBCreateEx	Pointer to callback function to be called after the file header has been read. See LPFNIG_DIB_CREATE_EX.
lpPrivateData	Pointer to a private data area. This pointer will be passed to the callback functions.

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 Professional.

Actual set of pixel formats supported by this function can be narrower, depending on the implementation of the user-defined callback function.

Sample:

None

Example:

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

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HIGEAR hIGear = 0;      /* handle ret'd by ImageGear  */
char* lpWhereFile; /* ptr to image file in mem   */
AT_UINT nWholeSize;    /* Size of image in memory */
AT_ERRCOUNT nErrcount;  /* to test for errors         */

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

//...

// Destroy the image
if(IG_image_is_valid(hIGear))
{
    IG_image_delete(hIGear);
}

If you set nPage to < 1, ImageGear will default the value to 1; if you set nPage to greater than the number of pages in the document, ImageGear will default the value to the last page number. This same default procedure applies to the nTileNum parameter as well.