CentrED/Imaging/ImagingColors.pas

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{
Vampyre Imaging Library
by Marek Mauder
https://github.com/galfar/imaginglib
https://imaginglib.sourceforge.io
- - - - -
This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at https://mozilla.org/MPL/2.0.
}
{ This unit contains functions for manipulating and converting color values.}
unit ImagingColors;
interface
{$I ImagingOptions.inc}
uses
SysUtils, ImagingTypes, ImagingUtility;
{ Converts RGB color to YUV.}
procedure RGBToYUV(R, G, B: Byte; var Y, U, V: Byte);
{ Converts YIV to RGB color.}
procedure YUVToRGB(Y, U, V: Byte; var R, G, B: Byte);
{ Converts RGB color to YCbCr as used in JPEG.}
procedure RGBToYCbCr(R, G, B: Byte; var Y, Cb, Cr: Byte);
{ Converts YCbCr as used in JPEG to RGB color.}
procedure YCbCrToRGB(Y, Cb, Cr: Byte; var R, G, B: Byte);
{ Converts RGB color to YCbCr as used in JPEG.}
procedure RGBToYCbCr16(R, G, B: Word; var Y, Cb, Cr: Word);
{ Converts YCbCr as used in JPEG to RGB color.}
procedure YCbCrToRGB16(Y, Cb, Cr: Word; var R, G, B: Word);
{ Converts RGB color to CMY.}
procedure RGBToCMY(R, G, B: Byte; var C, M, Y: Byte);
{ Converts CMY to RGB color.}
procedure CMYToRGB(C, M, Y: Byte; var R, G, B: Byte);
{ Converts RGB color to CMY.}
procedure RGBToCMY16(R, G, B: Word; var C, M, Y: Word);
{ Converts CMY to RGB color.}
procedure CMYToRGB16(C, M, Y: Word; var R, G, B: Word);
{ Converts RGB color to CMYK.}
procedure RGBToCMYK(R, G, B: Byte; var C, M, Y, K: Byte);
{ Converts CMYK to RGB color.}
procedure CMYKToRGB(C, M, Y, K: Byte; var R, G, B: Byte);
{ Converts RGB color to CMYK.}
procedure RGBToCMYK16(R, G, B: Word; var C, M, Y, K: Word);
{ Converts CMYK to RGB color.}
procedure CMYKToRGB16(C, M, Y, K: Word; var R, G, B: Word);
{ Converts RGB color to YCoCg.}
procedure RGBToYCoCg(R, G, B: Byte; var Y, Co, Cg: Byte);
{ Converts YCoCg to RGB color.}
procedure YCoCgToRGB(Y, Co, Cg: Byte; var R, G, B: Byte);
//procedure RGBToHSL(R, G, B: Byte; var H, S, L: Byte);
//procedure HSLToRGB(H, S, L: Byte; var R, G, B: Byte);
implementation
procedure RGBToYUV(R, G, B: Byte; var Y, U, V: Byte);
begin
Y := ClampToByte(Round( 0.257 * R + 0.504 * G + 0.098 * B) + 16);
V := ClampToByte(Round( 0.439 * R - 0.368 * G - 0.071 * B) + 128);
U := ClampToByte(Round(-0.148 * R - 0.291 * G + 0.439 * B) + 128);
end;
procedure YUVToRGB(Y, U, V: Byte; var R, G, B: Byte);
var
CY, CU, CV: LongInt;
begin
CY := Y - 16;
CU := U - 128;
CV := V - 128;
R := ClampToByte(Round(1.164 * CY - 0.002 * CU + 1.596 * CV));
G := ClampToByte(Round(1.164 * CY - 0.391 * CU - 0.813 * CV));
B := ClampToByte(Round(1.164 * CY + 2.018 * CU - 0.001 * CV));
end;
procedure RGBToYCbCr(R, G, B: Byte; var Y, Cb, Cr: Byte);
begin
Y := ClampToByte(Round( 0.29900 * R + 0.58700 * G + 0.11400 * B));
Cb := ClampToByte(Round(-0.16874 * R - 0.33126 * G + 0.50000 * B + 128));
Cr := ClampToByte(Round( 0.50000 * R - 0.41869 * G - 0.08131 * B + 128));
end;
procedure YCbCrToRGB(Y, Cb, Cr: Byte; var R, G, B: Byte);
begin
R := ClampToByte(Round(Y + 1.40200 * (Cr - 128)));
G := ClampToByte(Round(Y - 0.34414 * (Cb - 128) - 0.71414 * (Cr - 128)));
B := ClampToByte(Round(Y + 1.77200 * (Cb - 128)));
end;
procedure RGBToYCbCr16(R, G, B: Word; var Y, Cb, Cr: Word);
begin
Y := ClampToWord(Round( 0.29900 * R + 0.58700 * G + 0.11400 * B));
Cb := ClampToWord(Round(-0.16874 * R - 0.33126 * G + 0.50000 * B + 32768));
Cr := ClampToWord(Round( 0.50000 * R - 0.41869 * G - 0.08131 * B + 32768));
end;
procedure YCbCrToRGB16(Y, Cb, Cr: Word; var R, G, B: Word);
begin
R := ClampToWord(Round(Y + 1.40200 * (Cr - 32768)));
G := ClampToWord(Round(Y - 0.34414 * (Cb - 32768) - 0.71414 * (Cr - 32768)));
B := ClampToWord(Round(Y + 1.77200 * (Cb - 32768)));
end;
procedure RGBToCMY(R, G, B: Byte; var C, M, Y: Byte);
begin
C := 255 - R;
M := 255 - G;
Y := 255 - B;
end;
procedure CMYToRGB(C, M, Y: Byte; var R, G, B: Byte);
begin
R := 255 - C;
G := 255 - M;
B := 255 - Y;
end;
procedure RGBToCMY16(R, G, B: Word; var C, M, Y: Word);
begin
C := 65535 - R;
M := 65535 - G;
Y := 65535 - B;
end;
procedure CMYToRGB16(C, M, Y: Word; var R, G, B: Word);
begin
R := 65535 - C;
G := 65535 - M;
B := 65535 - Y;
end;
procedure RGBToCMYK(R, G, B: Byte; var C, M, Y, K: Byte);
begin
RGBToCMY(R, G, B, C, M, Y);
K := Min(C, Min(M, Y));
if K = 255 then
begin
C := 0;
M := 0;
Y := 0;
end
else
begin
C := ClampToByte(Round((C - K) / (255 - K) * 255));
M := ClampToByte(Round((M - K) / (255 - K) * 255));
Y := ClampToByte(Round((Y - K) / (255 - K) * 255));
end;
end;
procedure CMYKToRGB(C, M, Y, K: Byte; var R, G, B: Byte);
begin
R := (255 - (C - MulDiv(C, K, 255) + K));
G := (255 - (M - MulDiv(M, K, 255) + K));
B := (255 - (Y - MulDiv(Y, K, 255) + K));
end;
procedure RGBToCMYK16(R, G, B: Word; var C, M, Y, K: Word);
begin
RGBToCMY16(R, G, B, C, M, Y);
K := Min(C, Min(M, Y));
if K = 65535 then
begin
C := 0;
M := 0;
Y := 0;
end
else
begin
C := ClampToWord(Round((C - K) / (65535 - K) * 65535));
M := ClampToWord(Round((M - K) / (65535 - K) * 65535));
Y := ClampToWord(Round((Y - K) / (65535 - K) * 65535));
end;
end;
procedure CMYKToRGB16(C, M, Y, K: Word; var R, G, B: Word);
begin
R := 65535 - (C - MulDiv(C, K, 65535) + K);
G := 65535 - (M - MulDiv(M, K, 65535) + K);
B := 65535 - (Y - MulDiv(Y, K, 65535) + K);
end;
procedure RGBToYCoCg(R, G, B: Byte; var Y, Co, Cg: Byte);
begin
// C and Delphi's SHR behaviour differs for negative numbers, use div instead.
Y := ClampToByte(( R + G shl 1 + B + 2) div 4);
Co := ClampToByte(( R shl 1 - B shl 1 + 2) div 4 + 128);
Cg := ClampToByte((-R + G shl 1 - B + 2) div 4 + 128);
end;
procedure YCoCgToRGB(Y, Co, Cg: Byte; var R, G, B: Byte);
var
CoInt, CgInt: Integer;
begin
CoInt := Co - 128;
CgInt := Cg - 128;
R := ClampToByte(Y + CoInt - CgInt);
G := ClampToByte(Y + CgInt);
B := ClampToByte(Y - CoInt - CgInt);
end;
{
File Notes:
-- TODOS ----------------------------------------------------
- nothing now
-- 0.26.3 Changes/Bug Fixes ---------------------------------
- Added RGB<>YCoCg conversion functions.
- Fixed RGB>>CMYK conversions.
-- 0.23 Changes/Bug Fixes -----------------------------------
- Added RGB<>CMY(K) conversion functions for 16 bit channels
(needed by PSD loading code).
-- 0.21 Changes/Bug Fixes -----------------------------------
- Added some color space conversion functions and LUTs
(RGB/YUV/YCrCb/CMY/CMYK).
-- 0.17 Changes/Bug Fixes -----------------------------------
- unit created (empty!)
}
end.