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Материал из DRKB


Эффект подсветки как при выделении значков на рабочем столе Windows.


{
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;


Source: http://www.swissdelphicenter.ch
ID: 03902