IG_image_channel_copy

This function creates a new image by copying a single channel from an existing image.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_image_channel_copy_create( LPCAT_CHANNEL_REF source, LPAT_CHANNEL_REF copy );

Arguments:

Name	Type	Description
source	LPCAT_CHANNEL_REF	Location of source channel to copy.
copy	LPAT_CHANNEL_REF	Location of new image with copied channel.

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++.

Example:

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/* Extract the first alpha channel if one exists / / Otherwise, extract the first color channel / AT_ERRCOUNT nErrcount; / Number of errors on stack / HIGEAR hImage; / Handle of source image / AT_CHANNEL_REF srcChan; / Channel to copy / AT_CHANNEL_REF dstChan; / New image with copied channel / enumIGColorSpaceIDs cs; / Source image's color space / AT_INT nColorChannels; / Number of color channels / nErrcount = IG_load_file("alpha.tif", &hImage); nErrcount = IG_image_colorspace_get(hImage, &cs); nColorChannels = IG_util_colorspace_color_count_get(cs); srcChan.hImage = hImage; if (IG_util_colorspace_contains_alpha(cs)) srcChan.uNumber = nColorChannels; / First alpha channel / else srcChan.uNumber = 0; / First color channel */ nErrcount = IG_image_channel_copy_create(&srcChan, &dstChan); hCopy = dstChan.hImage; nErrcount = IG_save_file(dstChan.hImage, "alpha.bmp", IG_SAVE_BMP_UNCOMP); nErrcount = IG_image_delete(hImage);

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/* Extract the first alpha channel if one exists */
/* Otherwise, extract the first color channel */
AT_ERRCOUNT nErrcount;  /* Number of errors on stack */
HIGEAR hImage;          /* Handle of source image */
AT_CHANNEL_REF srcChan; /* Channel to copy */
AT_CHANNEL_REF dstChan; /* New image with copied channel */
enumIGColorSpaceIDs cs; /* Source image's color space */
AT_INT nColorChannels;  /* Number of color channels */
nErrcount = IG_load_file("alpha.tif", &hImage);
nErrcount = IG_image_colorspace_get(hImage, &cs);
nColorChannels = IG_util_colorspace_color_count_get(cs);
srcChan.hImage = hImage;
if (IG_util_colorspace_contains_alpha(cs))
    srcChan.uNumber = nColorChannels; /* First alpha channel */
else
    srcChan.uNumber = 0; /* First color channel */
nErrcount = IG_image_channel_copy_create(&srcChan, &dstChan);
hCopy = dstChan.hImage;
nErrcount = IG_save_file(dstChan.hImage, "alpha.bmp", 
    IG_SAVE_BMP_UNCOMP);
nErrcount = IG_image_delete(hImage);

Remarks:

Specify in source the image and channel index to copy. If the copy is successful, copy will contain the HIGEAR handle of a newly allocated image containing the copied channel. The channel index in copy will always be set to 0. You are responsible for freeing the new image with IG_image_delete.