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Changing TColor to darker and lighter ... did you ever try it? It can be a b*tch ...
Here two procedure that make it easier on you.
Usage:
Canvas.Brush.Color:=Lighter(clBlue,20); // sets the color to 20% lighter than clBlue
Note: under Lazarus you'll need to add "LclIntf" to your uses clause (GetRValue etc. are Windows calls and Lazarus is crossplatform)
function Darker(MyColor:TColor; Percent:Byte):TColor;
var r,g,b:Byte;
begin
MyColor:=ColorToRGB(MyColor);
r:=GetRValue(MyColor);
g:=GetGValue(MyColor);
b:=GetBValue(MyColor);
r:=r-muldiv(r,Percent,100); //Percent% closer to black
g:=g-muldiv(g,Percent,100);
b:=b-muldiv(b,Percent,100);
result:=RGB(r,g,b);
end;
function Lighter(MyColor:TColor; Percent:Byte):TColor;
var r,g,b:Byte;
begin
MyColor:=ColorToRGB(MyColor);
r:=GetRValue(MyColor);
g:=GetGValue(MyColor);
b:=GetBValue(MyColor);
r:=r+muldiv(255-r,Percent,100); //Percent% closer to white
g:=g+muldiv(255-g,Percent,100);
b:=b+muldiv(255-b,Percent,100);
result:=RGB(r,g,b);
end;
Thank you. Your guide code is good. It's easy for me to customize the TColor.
I forgot to mention one unit to include in the uses clause, so here the full list:
uses ... LclIntf, lcltype ...;
Note: I am a little late to the thread, but here is what I use. I write verbose delphi code with structure so it makes sense if I see it years later.
function GetColorOffSet( const AColor: TColor; const AOffSetPercentage: integer = 50 { AOffSetPercentage Range is 1..99} ): TColor;
function SetValuesForRGB( var ALuminance: double; var ARed: integer; var AGreen: integer; var ABlue: integer ): boolean;
var
AResult: boolean;
ARGB: LongInt;
begin
AResult := False;
try
try
ARGB := ColorToRGB( AColor );
ARed := GetRValue( ARGB );
AGreen := GetGValue( ARGB );
ABlue := GetBValue( ARGB );
ALuminance := (0.2126 * ARed) + (0.7152 * AGreen) + (0.0722 * ABlue);
AResult := True;
except
AResult := False;
end;
finally
SetValuesForRGB := AResult;
end;
end;
function GetOffSetColor( ALuminance: double; ARed: integer; AGreen: integer; ABlue: integer ): TColor;
function ValidateRGB( AValue: integer ): integer;
begin
try
if AValue > 255 then
begin
AValue := 255
end
else if AValue < 0 then
begin
AValue := 0;
end;
finally
ValidateRGB := AValue;
end;
end;
const
csOnePercentColor = 2.55;
cdHalfOfRGB = 127.5;
var
AResult: TColor;
begin
AResult := AColor;
try
try
if ALuminance <= cdHalfOfRGB then { lighter increases RGB Values }
begin
ARed := ValidateRGB( Trunc( ARed + ( AOffSetPercentage * csOnePercentColor )));
AGreen := ValidateRGB( Trunc( AGreen + ( AOffSetPercentage * csOnePercentColor )));
ABlue := ValidateRGB( Trunc( ABlue + ( AOffSetPercentage * csOnePercentColor )));
end
else { darker decreases RGB Values }
begin
ARed := ValidateRGB( Trunc( ARed - ( AOffSetPercentage * csOnePercentColor )));
AGreen := ValidateRGB( Trunc( AGreen - ( AOffSetPercentage * csOnePercentColor )));
ABlue := ValidateRGB( Trunc( ABlue - ( AOffSetPercentage * csOnePercentColor )));
end;
AResult := RGB( ARed, AGreen, ABlue );
except
AResult := AColor;
end;
finally
GetOffSetColor := AResult;
end;
end;
var
AResult: TColor;
ARed: integer;
AGreen: integer;
ABlue: integer;
ALuminance: double;
begin
AResult := AColor;
try
if (AOffSetPercentage > 0) and (AOffSetPercentage < 100) then
begin
if SetValuesForRGB( ALuminance, ARed, AGreen, ABlue ) then
begin
AResult := GetOffSetColor( ALuminance, ARed, AGreen, ABlue );
end;
end;
finally
GetColorOffSet := AResult;
end;
end;
Hi slincke!
Thank you for the contribution! Always good to have options right? 😊
Note: I've edited your post to have it code formatted.