function MD5FileTextPng(filename: AnsiString): AnsiString;

var

  buf: array[..MAX_PATH - ] of Char;

  path: AnsiString;

  stream: TFileStream;

  destStream: TMemoryStream;

  destfile, tmpText: string;

  I, len: Integer;

  endbuf: array[..] of Byte;

  firstChar: Byte;

  strstream: TStringStream;

const

  pngEndBuf: array[..] of Byte = ($AE, $, $, $);

begin

  GetTempPath(Length(buf), @buf[]);

  path := AnsiString(string(buf));

  tmpText := ExtractFileName(filename);

  tmpText := Copy(tmpText, , Length(tmpText) - );

  strstream := TStringStream.Create(tmpText, TEncoding.UTF8);

  strstream.Position := ;

  stream := TFileStream.Create(filename, fmOpenRead);

  try

    destStream := TMemoryStream.Create;

    try

      stream.Position := ;

      for I :=  to stream.Size -  do

        begin

          stream.Read(firstChar, );

          if firstChar <> $AE then

            Continue;

          stream.Position := stream.Position - ;

          stream.Read(endbuf[], );

          if CompareMem(@endbuf[], @pngEndBuf[], ) then

          begin

            len := stream.Position;

            Break;

          end;

        end;

      stream.Position := ;

      destStream.CopyFrom(stream, len);

      destfile := path + '\' + GetRamdomText();

      if FileExists(destfile) then

        DeleteFile(destfile);

      destStream.CopyFrom(strstream, strstream.Size);

      destStream.SaveToFile(destfile);

      strstream.Free;

      Result := MD5F(destfile);

    finally

      destStream.Free;

    end;

  finally

    stream.Free;

  end;

  if FileExists(destfile) then

    DeleteFile(destfile);

end;

unit uFixpng;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, uMD5, Vcl.StdCtrls, Vcl.FileCtrl,

  System.IOUtils, System.Types, Vcl.Samples.Gauges;

type

  TForm2 = class(TForm)

    Edit1: TEdit;

    Button1: TButton;

    Label1: TLabel;

    Gauge1: TGauge;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Edit1DblClick(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form2: TForm2;

implementation

{$R *.dfm}

function FixPng(filename: AnsiString; destFileName: string): Boolean;

var

  stream: TFileStream;

  destStream: TMemoryStream;

  I, len: Integer;

  endbuf: array[..] of Byte;

  firstChar: Byte;

const

  pngEndBuf: array[..] of Byte = ($AE, $, $, $);

begin

  stream := TFileStream.Create(filename, fmOpenRead);

  try

    destStream := TMemoryStream.Create;

    try

      stream.Position := ;

      for I :=  to stream.Size -  do

        begin

          stream.Read(firstChar, );

          if firstChar <> $AE then Continue;

          stream.Position := stream.Position - ;

          stream.Read(endbuf[], );

          if CompareMem(@endbuf[], @pngEndBuf[], ) then

          begin

            len := stream.Position;

            Break;

          end;

        end;

      stream.Position := ;

      destStream.CopyFrom(stream, len);

      destStream.SaveToFile(destFileName);

    finally

      destStream.Free;

    end;

  finally

    stream.Free;

  end;

  Result := True;

end;

procedure TForm2.Button1Click(Sender: TObject);

var

  files: TStringDynArray;

  path, destPath, destFile: string;

  I: Integer;

begin

  TButton(Sender).Enabled := False;

  Gauge1.Visible := True;

  try

    path := Trim(Edit1.Text);

    if not TDirectory.Exists(path) then Exit;

    files := TDirectory.GetFiles(path, '*.png');

    destPath := TPath.Combine(path, 'Fix-' + FormatDateTime('hhnnss', Now));

    if not TDirectory.Exists(destPath) then

      TDirectory.CreateDirectory(destPath);

    Gauge1.Progress := ;

    Gauge1.MinValue := ;

    Gauge1.MaxValue := Length(files);

    for I := Low(files) to High(files) do

    begin

      destFile := TPath.Combine(destPath, ExtractFileName(files[I]));

      FixPng(files[I], destFile);

      Gauge1.Progress := Gauge1.Progress + ;

      Application.ProcessMessages;

    end;

  finally

    TButton(Sender).Enabled := True;

    Gauge1.Visible := False;

  end;

end;

procedure TForm2.Edit1DblClick(Sender: TObject);

var

  path: string;

begin

  SelectDirectory('选择png文件夹', '', path);

  Edit1.Text := path;

end;

procedure TForm2.FormCreate(Sender: TObject);

begin

  Position := poScreenCenter;

end;

end.

object Form2: TForm2

  Left =

  Top =

  Caption = ##'png'

  ClientHeight =

  ClientWidth =

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  PixelsPerInch =

  TextHeight =

  object Label1: TLabel

    Left =

    Top =

    Width =

    Height =

    Caption = 'PNG'####

  end

  object Gauge1: TGauge

    Left =

    Top =

    Width =

    Height =

    Align = alBottom

    Color = clNavy

    ParentColor = False

    Progress =

    ShowText = False

    Visible = False

  end

  object Edit1: TEdit

    Left =

    Top =

    Width =

    Height =

    TabOrder =

    OnDblClick = Edit1DblClick

  end

  object Button1: TButton

    Left =

    Top =

    Width =

    Height =

    Caption = ####

    TabOrder =

    OnClick = Button1Click

  end

end