ImageGear for Java
ImageGear Support
| ImageGear for Java User Guide > Using ImageGear for Java > Working with Spot Colors > ImageGear Support |
An image may contain multiple Extra channels. An Extra channel can belong to one of the following subtypes: Mask, Spot, or Unknown. These channels can be mixed in arbitrary order. ImageGear does not use separate values from the ImGearColorSpaceIDs Enumeration for Mask and Spot channels. Instead, it uses the ImGearColorSpaceIDs.Ex and ImGearColorSpaceIDs.Unknown values to specify presence of any of these channels in an image.
ImageGear stores an array of ImGearExtraChannelInfo Classes in ImGearDIB Class. The length of this array must always be equal to the number of extra channels in the DIB. DIB constructors, color space and channel manipulation functions must ensure this.
If an entry of the info array is ImGearSpotChannelInfo Class, then the corresponding Extra channel is a Spot channel. The ImGearSpotChannelInfo Class contains information that is necessary for displaying the spot channel. ImageGear uses spot color channels for display and color space conversions, and saves them to output files when supported by the format. If the output format does not allow storing additional channels, ImageGear converts Spot channels, together with regular color channels, to the destination color space.
If an entry of the info array is ImGearMaskColorChannelInfo or ImGearMaskSpotChannelInfo then the corresponding Extra channel is a Mask channel. ImageGear uses Mask channels for display and saves them to output files when supported by format. However, it does not use them in color space conversions. If the output format does not allow storing additional channels, ImageGear ignores Mask channels in conversion to the destination color space.
If an entry is ImGearExtraChannelInfo Class, then the corresponding Extra channel is unknown. It is not used in display and color conversions, but preserved and saved to output files when possible.
Spot Color, Mask, and Extra channels can be appended after any regular color channels, in any order, including color spaces that contain an Alpha or Pre-multiplied Alpha channel.
ImageGear for Java can load extra channels from TIFF and PSD file formats. The extra channels are internally stored as specified above and saved back as extra channels when the output format is either TIFF or PSD. Spot color support is added to the raster color conversion mechanism, so when saving an image to a format that does not support extra channels the image spot channels are get blended to the base channels. The alpha channels are skipped in this case.
ImageGear for Java can load Adobe Color Books and apply the loaded colors for displaying spot channels. Color books API allows loading color books from file, enumerates loaded books and colors within a book, and retrieves info on the specific spot color. Processing code uses color books to convert spot colors to regular colors such as CMYK, RGB, etc.