ImageGear for C and C++ on Linux v20.0 - Updated
API Reference Guide > Core Component API Reference > Core Component Functions Reference > Image DIB Functions > IG_image_DIB_raster_pntr_get

This function gets a pointer to the beginning of pixel data for a raster in the given image.


Copy Code
AT_ERRCOUNT ACCUAPI IG_image_DIB_raster_pntr_get(
   HIGEAR hIGear,
   AT_PIXPOS row,
   AT_VOID** lplpRaster


Name Type Description
hIGear HIGEAR HIGEAR handle of image.
row AT_PIXPOS Row in image for which to retrieve raster pointer.
lplpRaster AT_VOID** Returned pointer to the 1st pixel in the raster.

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++.


Copy Code
AT_ERRCOUNT nErrcount;  // Number of errors on stack
HIGEAR hIGear;          // Handle of image
LPAT_VOID lpRst;        // Pointer to a raster

// Load image file "picture.bmp" from working directory
nErrcount = IG_load_file("picture.bmp", &hIGear);
if(nErrcount == 0)
    nErrcount = IG_image_DIB_raster_pntr_get(hIGear, 0, &lpRst);
    // ...
    // Destroy the image


Rasters are stored from top to bottom, are DWORD-padded on 32-bit platforms (QWORD-padded on 64-bit platforms), use 8, 16, or 32 bits to store channel values, and have alpha/extra channels included in-line with the color channels. For example, an RGB image with an alpha channel would be stored as: RGBA RGBA RGBA ...

If the image is 1bpp b/w, it is stored in a compressed run ends format. See IG_runs_row_get/IG_runs_row_set for a description of this format. It is recommended to use these functions to access run ends data, but you can use IG_image_DIB_raster_pntr_get() with the following restrictions:


Although ImageGear currently stores uncompressed (non-run ends) rasters continously, we do not recommend that you rely on this, as the internal storage format may change in the future. Use IG_image_DIB_raster_pntr_get to access each raster separately.

Is this page helpful?
Yes No
Thanks for your feedback.