ImageGear for C and C++ on Linux v20.0 - Updated
API Reference Guide > Core Component API Reference > Core Component Functions Reference > Load Functions > IG_load_raw_FD

This function creates an ImageGear image from the raw image data of the file whose File handle is fd.


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   AT_INT fd,
   AT_DIMENSION nHeight,
   UINT nBitsPerPixel,
   AT_MODE nFillOrder,
   AT_MODE nCompression,
   LPHIGEAR lphIGear


Name Type Description
fd AT_INT Handle of the open file containing the image to be loaded. This handle can be obtained from Microsoft Windows functions such as CreateFile(), and cast to AT_INT for passing to the function parameter. FILE pointers returned by functions such as fopen(), and file handles returned by functions such as _sopen_s() are not supported.
nWidth AT_DIMENSION The width, in pixels, of the image.
nHeight AT_DIMENSION The height, in pixels, of the image.
nBitsPerPixel UINT The Bits Per Pixel of the raw data to load.
nFillOrder AT_MODE Set to the fill order used in the image: Least Significant Bit first (LSB) or Most Significant Bit first (MSB). Use one of the ImageGear - defined constants: IG_FILL_LSB or IG_FILL_MSB.
  • For G3/G4 compressed data, this parameter specifies the Least/Most significant bit.
  • For 16 bit grayscale uncompressed images, this parameter specifies the Least/Most significant byte.
  • For any other bit depths and compressions, this parameter is ignored.
nCompression AT_MODE Compression used by the RAW image data. Set to one of enumIGCompressions constants.
lphIGear LPHIGEAR Returns a HIGEAR handle to the raw image data just loaded.

Return Value:

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

Supported Raster Image Formats:


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HIGEAR hIGear = 0;            // Will receive HIGEAR image handle
HANDLE fd;                    // File Descriptor handle

// Open a dile to read
fd = CreateFile(_T("Group4.raw"), GENERIC_READ,

    AT_ERRCOUNT nErrcount;  // Returned count of errors
    nErrcount = IG_load_raw_FD((AT_INT)fd, 2320, 3408, 1, IG_FILL_MSB, IG_COMPRESSION_CCITT_G4, &hIGear);


    // Destroy the image


A raw image file contains no header or identifying information. You must supply this function with all of the information needed to correctly parse the image data, including the compression, byte fill order, width, height, and bit depth. Currently, this function can be used to read raw image data from the following types of files: ABIC, CCITT - Group 3, Group 3 2D, Group 4, LZW, and raw uncompressed data.

The ABIC and LZW compression types are available as separate components to ImageGear. See ImageGear Components for details on working with ImageGear components.

The pointer must be positioned at the start of the data. (For example, your application should read or seek past any header that is present.)

Additionally, you can specify row and pixel alignment for the loading of uncompressed images using ALIGNMENT and UNCOMPRESSED_PACKED image control parameters, respectively. See RAW format reference for more information.

For uncompressed images only, ImageGear's Load Raw functions consider the coordinates (0,0) to refer to the lower-left corner of the bitmap.

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