end;
            transparent := True;
          end;
        end;
      ptmBit:
        begin
          TransparentColor := Color32(PNGObject.TransparentColor);
          PixelPtr := PColor32(@destBitmap.Bits[0]);
          for X := 0 to (destBitmap.Height - 1) * (destBitmap.Width - 1) do
          begin
            if PixelPtr^ = TransparentColor then
              PixelPtr^ := PixelPtr^ and $00FFFFFF;
            Inc(PixelPtr);
          end;
          transparent := True;
        end;
      ptmNone:
        transparent := False;
    end;
    result := true;
  finally
    if Assigned(PNGObject) then PNGObject.Free;
  end;
end;
//*********************************************************
// load PNG image file into Bitmap32
// input:   destBitmap: TBitmap32;    destination bitmap
//          filename: String;         name of PNG image file
// output:  transparent: boolean;     =true: alpha channel used
// return:  boolean;                  =true: png image file loaded
//---------------------------------------------------------
function LoadPNGintoBitmap32 (destBitmap: TBitmap32;
                              filename: String;
                              out transparent: boolean): boolean;
var
  FileStream: TFileStream;
begin
  result := false;
  try
    FileStream := TFileStream.Create(filename, fmOpenRead);
    try
      result := LoadPNGintoBitmap32(destBitmap, FileStream, transparent);
    finally
      FileStream.Free;
    end;
  except
  end;
end;


//*********************************************************
// convert Bitmap32 to PNG image
// input:   sourceBitmap      source bitmap 32 bit
//          paletted          =true: PixelFormat is pf8bit
//          transparent       =true: transparent pixels
//          bgColor           background color
//          compressionLevel  compression level, range 0..9, default = 9
//          interlaceMethod   interlaced method, use imNone or imAdam7
// return:  tPNGObject        PNG image object
//---------------------------------------------------------
function Bitmap32ToPNG (sourceBitmap: TBitmap32;
                        paletted, transparent: Boolean;
                        bgColor: TColor;
                        compressionLevel: TCompressionLevel = 9;
                        interlaceMethod: TInterlaceMethod = imNone): tPNGObject;
var
  bm: TBitmap;
  png: TPngObject;
  TRNS: TCHUNKtRNS;
  p: pngImage.PByteArray;
  x, y: Integer;
begin
  Result := nil;
  png := TPngObject.Create;
  try
    bm := TBitmap.Create;
    try
      bm.Assign (sourceBitmap);        // convert data into bitmap
      // force paletted on TBitmap, transparent for the web must be 8bit
      if paletted then
        bm.PixelFormat := pf8bit;
      png.interlaceMethod := interlaceMethod;
      png.compressionLevel := compressionLevel;
      png.Assign(bm);                  // convert bitmap into PNG
    finally
      FreeAndNil(bm);
    end;
    if transparent then begin
      if png.Header.ColorType in [COLOR_PALETTE] then begin
        if (png.Chunks.ItemFromClass(TChunktRNS) = nil) then png.CreateAlpha;
        TRNS := png.Chunks.ItemFromClass(TChunktRNS) as TChunktRNS;
        if Assigned(TRNS) then TRNS.TransparentColor := bgColor;
      end;

      begin
        for y := 0 to png.Header.Height - 1 do begin
          p := png.AlphaScanline[y];
          for x := 0 to png.Header.Width - 1

      try
        png.SaveToStream (FileStream);
        result := true;
      finally
        png.Free;
      end;
    finally
      FileStream.Free;
    end;
  except
  end;
end;
*)


//*********************************************************
// code example of loading and saving a PNG image file
//---------------------------------------------------------
procedure PNGExample;
var  transparent: boolean;
     myBitmap: tBitmap32;
begin
  myBitmap := TBitmap32.Create;
  transparent := true;
  if LoadPNGintoBitmap32 (MyBitmap, 'example1.png', transparent)
  then begin
    if transparent then
      // add anything else that should be on transparent PNG image...
      MyBitmap.DrawMode := dmBlend
    else
      MyBitmap.DrawMode := dmOpaque;


    SaveBitmap32ToPNG (myBitmap, transparent, clBlack, 'savetest.png', 5);
  end;
  myBitmap.Free;
end;


begin
  // PNGExample;     // delete comment to test loading and saving PNG image
end.