L_JP2_JPXBITMAPS

typedef struct _tagL_JP2_JPXBITMAPS
{
   L_UINT32             uStructSize;
   BITMAPHANDLE         ColorBitmap;
   eJP2CODESTREAMFORMAT eColorFormat;
   BITMAPHANDLE         OpacityBitmap;
   eJP2CODESTREAMFORMAT eOpacityFormat;
   BITMAPHANDLE         PreOpacityBitmap;
   eJP2CODESTREAMFORMAT ePreOpacityFormat;
}L_JP2_JPXBITMAPS,   *pL_JP2_JPXBITMAPS;

The L_JP2_JPXBITMAPS structure provides information about layer channels.

Member	Description
uStructSize	Size of this structure, in bytes. Use the sizeof operator to calculate this value.
ColorBitmap	Color channels. This image specifies a layer color channels codestream.
eColorFormat	This field specifies the compression type of a color channels codestream. This value is used only when saving a layer (i.e. LJp2FileFormat::SaveComposite and LJp2FileFormat::SaveCompositeMemory functions) otherwise it is ignored.
OpacityBitmap	Opacity channels. This image specifies a layer opacity channels codestream.
eOpacityFormat	This field specifies the compression type of an opacity channels codestream. This value is used only when saving a layer (i.e. LJp2FileFormat::SaveComposite and LJp2FileFormat::SaveCompositeMemory functions) otherwise it is ignored.
PreOpacityBitmap	Pre-Multiplied Opacity channels. This image specifies a layer pre-multiplied opacity channels codestream.
ePreOpacityFormat	This field specifies the compression type of a pre-multiplied opacity channels codestream. This value is used only when saving a layer (i.e. LJp2FileFormat::SaveComposite and LJp2FileFormat::SaveCompositeMemory functions) otherwise it is ignored.

Comments

The L_JP2_JPXBITMAPS structure specifies the layer color, opacity, pre-multiplied opacity, and compression information. If any of these bitmaps is not allocated that means the layer has no channel of this type.