Handling CMYK Files as Separate Bitmaps

LEADTOOLS supports loading TIFF CMYK files without converting the data to BGR. This is done by loading each CMYK plane as a separate LEADTOOLS bitmap using the LoadFileCMYKArray method. Alpha channel information can be loaded or ignored as follows:

to ignore alpha information, set the CMYKRasterCount property to 4.

Or :

to load alpha information, set the CMYKRasterCount property to 5. (The alpha channel will be stored in the 5th element of the array).

Call the LoadFileCMYKArray method to load the CMYK planes and fill the CMYKRaster property.

If the source file is not in the TIFF CMYK format, load the bitmap normally with the LoadResize method, the Load method, the LoadOffset method, or the LoadMemory method and then obtain the CMYK planes by calling the ColorSeparate method.

Paint the bitmaps by passing a valid Raster IO object to the RasterIO property and passing TRUE to the EnablePaintCMYKArray property.

To save the bitmap as TIFF CMYK, call the SaveFileCMYKArray method.

To save the array of bitmaps to a file format not supported by this function, call the ColorMerge method to create a BGR bitmap and save the generated bitmap using the Save method.

The bitmap can be manipulated by manipulating each plane independently. Be careful when doing this. Some transformations should be done to all of the planes, while others should be done only to a particular plane.

For example, when performing a spatial transformation (flip, resize, rotate, etc), perform the same spatial transformation on all of the planes. Otherwise, there may be unwanted or unexpected results.

Other transformations should be done to a particular plane. For example, the K plane controls the amount of black ink. Changing the intensity of the K plane will darken or lighten the bitmap. Changing the brightness of one of the other planes will change the color rather than the image brightness. Be sure to study how the CMYK planes are combined to make the final image, in order to have a good understanding of what is needed to achieve a particular result.