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Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

{ 
Question: 
  Does anyone know of a way that I can achieve the same effect on a bitmap 
  that windows achieves when you single click on an icon on the desktop?  In 
  other words, I want to "sorta highlight" a bitmap and let the user know that 
  it"s selected. 

Answer: 

  To me it appears as if the icons on my desktop are highlighted by overlaying 
  them with a certain color, so I guess the following routine is of use. 
}


 procedure Highlight(aSource, ATarget: TBitmap; AColor: TColor);
 //alters ASource to ATarget by making it appear as if 
//looked through 
//colored glass as given by AColor 
//ASource, ATarget must have been created. 
//Isn"t as slow as it looks. 
//Physics courtesy of a post by K.H. Brenner 
var i, j: Integer;
   s, t: pRGBTriple;
   r, g, b: byte;
   cl: TColor;
 begin
   cl := ColorToRGB(AColor);
   r := GetRValue(cl);
   g := GetGValue(cl);
   b := GetBValue(cl);
   aSource.PixelFormat := pf24bit;
   ATarget.PixelFormat := pf24bit;
   ATarget.Width := aSource.Width;
   ATarget.Height := aSource.Height;
   for i := 0 to aSource.Height - 1 do
   begin
     s := ASource.Scanline[i];
     t := ATarget.Scanline[i];
     for j := 0 to aSource.Width - 1 do
     begin
       t^.rgbtBlue := (b * s^.rgbtBlue) div 255;
       t^.rgbtGreen := (g * s^.rgbtGreen) div 255;
       t^.rgbtRed := (r * s^.rgbtRed) div 255;
       inc(s);
       inc(t);
     end;
   end;
 end;

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