Emulation Tables (Delphi 4.0)

The LEAD Color Conversion toolkit provides emulation tables as one of its conversion methods. This method however is provided only for the following conversions:

CMYK to RGB.

CIELab to RGB

and RGB to CIELab

The Emulation tables' method supports both built-in and custom options. For built-in emulation tables, use the USE_ET option. The custom emulation tables' option, USE_CUSTOM_ET, provides custom conversion using user-supplied images converted from the source images distributed with the library by any tool, as follows:

A set of images, already converted and ready for use (dst_cmyk2rgb_image.tif, dst_rgb2lab_image.tif, and dst_lab2rgb_image.tif), is provided. However, using the provided set of converted images will produce the same results as the built-in emulation tables.

The code below shows how a conversion can be done using the built-in tables:

procedure Tables_Convert_CMYKToRGB({in}pInput: Pointer; {out}pOutput: Pointer; {in}nWidth: Integer; {in}nHeight: Integer);
var
   ClrHandle : THandle (*Color Handle*);
   params : CONVERSION_PARAMS (*Conversion options*);
begin

   (* Zero initialize, this step is important*)
   ZeroMemory (@params, SizeOf (CONVERSION_PARAMS));

   (*
    * Conversion with options.
    * The conversion will be done with the options specified in the
    * params variable.
   *)

   (* Set the params size *)
   params.uStructSize := SizeOf (CONVERSION_PARAMS);

   (* We want to use built-in emulation tables *)
   params.nMethod := USE_ET;

   (* set the active conversion method *)
   params.nActiveMethod := USE_ET;

   (* initialize the color conversion *)
   L_ClrInitL_ClrInit (@ClrHandle, (* pointer to color handle to be returned*)
             CCS_CMYK,    (* input color space *)
             CCS_RGB,     (* output color space *)
             @params      (* pointer to the initialization options *)
            );

   (* Convert the image buffer *)
   L_ClrConvert (ClrHandle, (* conversion handle *)
                 pInput,    (* input buffer *)
                 pOutput,   (* output buffer *)
                 nWidth,     (* pixels width *)
                 nHeight,   (* pixels height *)
                 0,         (* 0 bytes align *)
                 0);        (* 0 bytes align *)

   (* free the conversion *)
   L_ClrFree (ClrHandle);
end;

The code below shows how a conversion can be done using user-defined tables:

procedure Tables_Convert_CMYKToRGB({in}pInput: Pointer; {out}pOutput: Pointer; {in}nWidth: Integer; {in}nHeight: Integer);
var
   ClrHandle : THandle (*Color Handle*);
   params : CONVERSION_PARAMS (*Conversion options*);
begin

   (* Zero initialize, this step is important*)
   ZeroMemory (@params, SizeOf (CONVERSION_PARAMS));

   (*
    * Conversion with options.
    * The conversion will be done with the options specified in the
    * params variable.
   *)

   (* Set the params size *)
   params.uStructSize := SizeOf (CONVERSION_PARAMS);

   (* We want to use built-in emulation tables *)
   params.nMethod := USE_CUSTOM_ET;

   (* set the active conversion method *)
   params.nActiveMethod := USE_CUSTOM_ET;

   (* set the emulation tables *)
   StrCopy(params.sInputProfile, 'C:\RGBImage.tif');

   (* initialize the color conversion *)
   L_ClrInit (@ClrHandle, (* pointer to color handle to be returned*)
             CCS_CMYK,    (* input color space *)
             CCS_RGB,     (* output color space *)
             @params      (* pointer to the initialization options *)
            );

   (* Convert the image buffer *)
   L_ClrConvert (ClrHandle, (* conversion handle *)
                 pInput,    (* input buffer *)
                 pOutput,   (* output buffer *)
                 nWidth,     (* pixels width *)
                 nHeight,   (* pixels height *)
                 0,         (* 0 bytes align *)
                 0);        (* 0 bytes align *)

   (* free the conversion *)
   L_ClrFree (ClrHandle);
end;