Author: Tomas Rutkauskas

How to disable the transparent part of a TSpeedButton from clicking

Answer:
1   
2   procedure TMFSpeedButton.MouseDown(Button: TMouseButton; Shift: TShiftState; X, Y:
3     Integer);
4   var
5     ScreenDC: HDC;
6     Transp, Bits: Boolean;
7   begin
8     inherited MouseDown(Button, Shift, X, Y);
9     if (Button = mbLeft) and Enabled then
10    begin
11      Bits := False;
12      Transp := False;
13      ScreenDC := GetDC(0);
14      try
15        {Transparent color is color of form background. Test for True Color 24bit
16  		  or  more, because on lower color depth the color is blended, so it works only
17  			on true color for some colors. If it is for example clBlack, it works
18  			on everything}
19        Bits := GetDeviceCaps(ScreenDC, BITSPIXEL) >= 24;
20        {test for desired color}
21        Transp := GetPixel(ScreenDC, Mouse.CursorPos.x, Mouse.CursorPos.Y) = 
22  $0094ADBD;
23      finally
24        ReleaseDC(0, ScreenDC);
25      end;
26      {leave procedure if test for transp. color was successful}
27      if Transp and Bits then
28        Exit;
29      if not FDown then
30      begin
31        FState := bsDown;
32        Invalidate;
33      end;
34      FDragging := True;
35    end;
36  end;