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...get an inverse color value to a color?
Autor: Neil Rubenking
[ Print tip ]  

Tip Rating (9):  
     


procedure EdBackColor(FontC: TColor; var EditableColor,
  ReadOnlyColor: TColor);
  // Calculate the luminance of the color using the simplified formula
  //     luminance = 0.25*red + 0.625*green + 0.125*blue
  // If greater than 0.5, use a dark background
var
  
R, G, B: Integer;
begin
  
R := GetRValue(FontC) * 2;
  G := GetGValue(FontC) * 5;
  B := GetBValue(FontC);
  if R + G + B < 1024 then
  begin
    
EditableColor := clWhite;
    ReadOnlyColor := clSilver;
  end
  else
  begin
    
EditableColor := clBlack;
    ReadOnlyColor := clDkGray;
  end;
end;

 

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