delphi JPG或BMP图片透明显示

procedure SaveBmpAsIcon(const Bmp: TBitmap; const Icon: string; const SmallIcon: Boolean;

const Transparent: Boolean; const X, Y: Integer);

//  Bmp        : Bitmap图片

//  Icon      : 最终输出的icon文件全路径和文件名。如果文件已经存在则会将其覆盖

//  SmallIcon  : True: 16x16 图标, False: 32x32 图标

//  Transparent: 确定是否按照参数X,Y的坐标色生成透明图标

//  X, Y      : 此参数指明坐标下的色值将会作为透明色替换全图

var

  PBI, MPBI: PBitmapInfo;

  IHS, MIHS, ImageSize, MImageSize: DWord;

  bmBuffer, MaskBuffer: Pointer;

  TID: TIconDir;

  TBIH: TBitmapInfoHeader;

  Bmx, Bmm: TBitmap;

  TranspCol: TColor;

  I, J: Integer;

begin

  Bmx:= TBitmap.Create;

  Bmm:= TBitmap.Create;

  try

    if SmallIcon then

    begin

      Bmx.Width:= GetSystemMetrics(SM_CXSMICON);

      Bmx.Height:= GetSystemMetrics(SM_CYSMICON);

    end

    else

    begin

      Bmx.Width:= GetSystemMetrics(SM_CXICON);

      Bmx.Height:= GetSystemMetrics(SM_CYICON);

    end;

    bmx.pixelformat:=pf24bit;

    Bmx.Canvas.StretchDraw(Rect(, , Bmx.Width, Bmx.Height), Bmp);

    TranspCol:= Bmx.Canvas.Pixels[X, Y];

    //TranspCol:= clWhite;

    Bmm.Assign(Bmx);

    Bmm.Mask(TranspCol);

    GetDIBSizes(Bmm.Handle, MIHS, MImageSize);

    GetDIBSizes(Bmx.Handle, IHS, ImageSize);

    MaskBuffer:= AllocMem(MImageSize);

    bmBuffer:= AllocMem(ImageSize);

    MPBI:= AllocMem(MIHS);

    PBI:= AllocMem(IHS);

    try

      if Transparent then

      begin

        for I:= to Bmx.Width- do

          for J:= to Bmx.Height- do

            if Bmx.Canvas.Pixels[I, J] = TranspCol then Bmx.Canvas.Pixels[I, J]:= ;

        with MPBI^.bmiHeader do

        begin

          biSize:= SizeOf(TBitmapInfoHeader);

          biWidth:= Bmm.Width;

          biHeight:= Bmm.Height;

          biPlanes:= ;

          biBitCount:= ;

          biCompression:= BI_RGB;

          biSizeImage:= MImageSize;

          biXPelsPerMeter:= ;

          biYPelsPerMeter:= ;

          biClrUsed:= ;

          biClrImportant:= ;

        end;

        GetDIBits(Bmm.Canvas.Handle, Bmm.Handle, , Bmm.height, MaskBuffer, MPBI^, DIB_RGB_COLORS);

      end;

      with PBI^.bmiHeader do

      begin

        biSize:= SizeOf(TBitmapInfoHeader);

        biWidth:= Bmx.Width;

        biHeight:= Bmx.Height;

        biPlanes:= ;

        biBitCount:= ;

        biCompression:= BI_RGB;

        biSizeImage:= ImageSize;

        biXPelsPerMeter:= ;

        biYPelsPerMeter:= ;

        biClrUsed:= ;

        biClrImportant:= ;

      end;

      GetDIBits(Bmx.Canvas.Handle, Bmx.Handle, , Bmx.Height, bmBuffer, PBI^, DIB_RGB_COLORS);

      with TBIH do

      begin

        biSize:= ;

        biWidth:= Bmx.Width;

        biHeight:= Bmx.Height * ;

        biPlanes:= ;

        biBitCount:= ;

        biCompression:= ;

        biSizeImage:= ImageSize;

        biXPelsPerMeter:= ;

        biYPelsPerMeter:= ;

        biClrUsed:= ;

        biClrImportant:= ;

      end;

      with TID do

      begin

        idReserved:=;

        idType:=;

        idCount:=;

        with idEntries[] do

        begin

          bWidth:=bmx.width;

          bHeight:=bmx.height;

          bColorCount:=;

          bReserved:=;

          wPlanes:=;

          wBitCount:=;

          dwBytesInRes:= SizeOf(TBitmapInfoHeader) + TBIH.biSizeImage + MImageSize;

          dwImageOffset:=  + TID.idCount * SizeOf(TIconDirEntry);

        end;

      end;

      with TFileStream.Create(Icon, fmCreate) do

      try

        Write(TID,  + TID.idCount * SizeOf(TIconDirEntry));

        Write(TBIH, SizeOf(TBitmapInfoheader));

        Write(bmBuffer^, TBIH.biSizeImage);

        Write(maskBuffer^, MImageSize);

      finally

        Free;

      end;

    finally

      FreeMem(MaskBuffer);

      FreeMem(bmBuffer);

      FreeMem(MPBI);

      FreeMem(PBI);

    end;

  finally

    Bmx.free;

    Bmm.free;

  end;

end;