Calculate a TColor between two other TColors (Views: 27)
Problem/Question/Abstract: I needed a function that calculates a TColor-Value between two others from an Extended. This Extended should be limited from two other Extended Variables. Answer: Solve 1: I needed a function that calculates a TColor-Value between two others from an Extended. This Extended should be limited from two other Extended Variables. All Values of "Pointvalue" less then "von" will return "Startcolor" and all Pointvalues greater than "Bis" gives EndColor back. Ist written with some Inline- Assemblercode. I think maybee its could be usefull for somebody else. function GetColorBetween(StartColor, EndColor: TColor; Pointvalue, Von, Bis: Extended): TColor; var F: Extended; r1, r2, r3, g1, g2, g3, b1, b2, b3: Byte; function CalcColorBytes(fb1, fb2: Byte): Byte; begin result := fb1; if fb1 < fb2 then Result := FB1 + Trunc(F * (fb2 - fb1)); if fb1 > fb2 then Result := FB1 - Trunc(F * (fb1 - fb2)); end; begin if Pointvalue <= Von then begin result := StartColor; exit; end; if Pointvalue >= Bis then begin result := EndColor; exit; end; F := (Pointvalue - von) / (Bis - Von); asm mov EAX, Startcolor cmp EAX, EndColor je @@exit mov r1, AL shr EAX,8 mov g1, AL shr Eax,8 mov b1, AL mov Eax, Endcolor mov r2, AL shr EAX,8 mov g2, AL shr EAX,8 mov b2, AL push ebp mov al, r1 mov dl, r2 call CalcColorBytes pop ecx push ebp Mov r3, al mov dL, g2 mov al, g1 call CalcColorBytes pop ecx push ebp mov g3, Al mov dL, B2 mov Al, B1 call CalcColorBytes pop ecx mov b3, al XOR EAX,EAX mov AL, B3 SHL EAX,8 mov AL, G3 SHL EAX,8 mov AL, R3 @@Exit: mov @result, eax end; end; Solve 2: //------------------------------------------------------------------------------ // Function for getting mixed color from two given colors, with a relative // distance from two colors determined by Position value inside // MinPosition..MaxPosition range // Author: Dmitri Papichev (c) 2001 // License type: Freeware //------------------------------------------------------------------------------ function GetMixedColor(const StartColor, EndColor: TColor; const MinPosition, Position, MaxPosition: integer): TColor; var Fraction: double; R, G, B, R0, G0, B0, R1, G1, B1: byte; begin {process Position out of range situation} if (MaxPosition < MinPosition) then begin raise Exception.Create ('GetMixedColor: MaxPosition is less then MinPosition'); end; {if} {if Position is outside MinPosition..MaxPosition range, the closest boundary is effectively substituted through the adjustment of Fraction} Fraction := Min(1, Max(0, (Position - MinPosition) / (MaxPosition - MinPosition))); {extract the intensity values} R0 := GetRValue(StartColor); G0 := GetGValue(StartColor); B0 := GetBValue(StartColor); R1 := GetRValue(EndColor); G1 := GetGValue(EndColor); B1 := GetBValue(EndColor); {calculate the resulting intensity values} R := R0 + Round((R1 - R0) * Fraction); G := G0 + Round((G1 - G0) * Fraction); B := B0 + Round((B1 - B0) * Fraction); {combine intensities in a resulting color} Result := RGB(R, G, B); end; {--GetMixedColor--} |