IG_DIB_area

IG_DIB_area_set

In This Topic

This function transfers pixels from the location pointed to by lpPixel into the rectangular portion of the image specified by rectangle lpRect.

Declaration:

	Copy Code
AT_ERRCOUNT ACCUAPI IG_DIB_area_set ( HIGEAR hIGear, const LPAT_RECT lpRect, const LPAT_PIXEL lpPixel, AT_MODE nPixelFormat );

Arguments:

Name	Type	Description
hIGear	HIGEAR	ImageGear HIGEAR handle of image
lpRect	const LPAT_RECT	Far pointer to an AT_RECT struct specifying the rectangular portion of the image bitmap to set
lpPixel	LPAT_PIXEL	Far pointer to first byte of your pixel data
nPixelFormat	AT_MODE	A constant such as IG_DIB_AREA_UNPACKED specifying in what form you are providing the pixels. The IG_DIB_AREA_... constants are listed in file accucnst.h.

Return Value:

Returns the number of ImageGear errors that occurred during this function call. If there are no errors, the return value is IGE_SUCCESS.

Supported Raster Image Formats:

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

Sample:

Pixel Access

Example:

	Copy Code
HIGEAR hIGear; /* HIGEAR handle of image / AT_RECT rcBlock; / The rectangular block to set / AT_PIXEL cPixelArray[400]; / The pixels to set / AT_DIMENSION nWid, nHi; / Receives the width & height of an image / UINT nBpp; / Bits per pixel / AT_ERRCOUNT nErrcount; / Receives the returned error counts / / Sets the upper left 20 x 20 pixels, to cPixArray[]: / rcBlock.top = rcBlock.left = 0; rcBlock.bottom = rcBlock.right = 20; / 20x20 area, 400 pixels / nErrcount = IG_image_dimensions_get ( hIGear, &nWid, &nHi, &nBpp ); / if ( nErrcount == 0 ) /* If valid image, dimensions obtained: / { if ( (nBpp <= 8) && (nWid >= 20) && (nHi >= 20) ) { /Array is too small for 24-bit) / INT row, col; pix; / For the loops below / AT_PIXEL nPixval; / pixel value to set / if (nBpp == 8) nPixval = 128; / Value to set if 8-bit / if (nBpp == 4) nPixval = 8; / Value to set if 4-bit / if (nBpp == 1) nPixval = 1; / Pixel ON if 1-bit / for ( pix=0,row=0; row<20; row++ ) / For all pixels in / for ( col=0; col<20; col++ )/ the 20 x 20 array: / cPixelArray[pix++] = nPixval; / Set unpacked in byte */ nErrcount = IG_DIB_area_set ( hIGear, &rcBlock, &cPixelArray[0], IG_DIB_AREA_UNPACKED ); } }

Copy Code

HIGEAR          hIGear;        /* HIGEAR handle of image */
AT_RECT         rcBlock;       /* The rectangular block to set   */
AT_PIXEL        cPixelArray[400];    /* The pixels to set */
AT_DIMENSION    nWid, nHi;     /* Receives the width & height of an image */
UINT            nBpp;          /* Bits per pixel   */
AT_ERRCOUNT     nErrcount;      /* Receives the returned error counts  */
/* Sets the upper left 20 x 20 pixels, to cPixArray[]:               */
rcBlock.top = rcBlock.left = 0;
rcBlock.bottom = rcBlock.right = 20;  /* 20x20 area, 400 pixels   */
nErrcount = IG_image_dimensions_get ( hIGear, &nWid, &nHi, &nBpp );  */
if ( nErrcount == 0 )      /* If valid image, dimensions obtained:  */
        {
        if ( (nBpp <= 8) && (nWid >= 20) && (nHi >= 20) )    
{       
/*Array is too small for 24-bit)     */
        INT           row, col; pix;     /* For the loops below  */
        AT_PIXEL      nPixval;          /* pixel value to set  */
        if (nBpp == 8) nPixval = 128;   /* Value to set if 8-bit   */
        if (nBpp == 4) nPixval = 8;     /* Value to set if 4-bit   */
        if (nBpp == 1) nPixval = 1;     /* Pixel ON if 1-bit    */
                for ( pix=0,row=0; row<20; row++ ) /* For all pixels in    */
                        for ( col=0; col<20; col++ )/* the 20 x 20 array:  */
                                cPixelArray[pix++] = nPixval;   
                                /* Set unpacked in byte    */
                nErrcount = IG_DIB_area_set ( hIGear, &rcBlock, &cPixelArray[0],
IG_DIB_AREA_UNPACKED );
}
        }

Remarks:

ImageGear's pixel access functions consider the coordinates (0,0) to refer to the upper left-hand corner of the bitmap data. They do not follow the DIB's orientation, which considers (0,0) to refer to the lower left-hand corner of the bitmap.

Use nPixelFormat = IG_DIB_AREA_DIB if you are providing the pixels in standard uncompressed DIB format. This means 1-bit or 4-bit pixels will be packed 8 to the byte or 2 to the byte respectively, left justified (first pixel uses most significant bit). 24-bit pixels are in 3 bytes, ordered Blue-Green-Red.
Use nPixelFormat = IG_DIB_AREA_UNPACKED if you are providing the pixels 1 pixel per byte (however, 3 bytes for a 24-bit pixel, ordered Blue-Green-Red). In this case, you provide 1-bit and 4-bit pixels one to a byte, right justified in the byte.