Base64

From Lazarus wiki
Jump to navigationJump to search

Various code examples to handle Base64 encoded strings.

Convert Base64 string to picture, 1

Example from forum member wp. 

procedure DecodeBase64ToStream(AStream: TStream; const s: string; strict:boolean=false);
var
  SD : String;
  Instream: TStringStream;
  Decoder: TBase64DecodingStream;
begin
  if Length(s)=0 then
    Exit;
  SD := S;
  while Length(Sd) mod 4 > 0 do
    SD := SD + '=';
  Instream:=TStringStream.Create(SD);
  try
    if strict then
      Decoder:=TBase64DecodingStream.Create(Instream,bdmStrict)
    else
      Decoder:=TBase64DecodingStream.Create(Instream,bdmMIME);
    try
       AStream.CopyFrom(Decoder, Decoder.Size);
       AStream.Position := 0;
    finally
      Decoder.Free;
    end;
  finally
    Instream.Free;
  end;
end;

var
  base64String: String =
    'iVBORw0KGgoAAAANSUhEUgAAARIAAAAdCAYAAABmFuNCAAAFPElEQVR4Xu2cy5oiIQyFdaPP'+
    'PCt1Nc9sbxyRTlcqJuFAYdvf9HGjllSAQ/grXGR/vV5vO76oABWgAhsU2BMkG9TjrVSACjwU'+
    'IEjoCFSACmxWwAXJ4XDY7fe73fX6scpg1nVtNLLZWzPEzqzyM6/3+sasdkT8kHlVlVo+/wSS'+
    '4/Hv7nY71XBlf7nD5M/j86zruvEimzW/Q8oSDbnMjhiZVX7m9V7fmNWOiB8yr7zvaw3diKQI'+
    'WF4CEd0ZZ1y3jahtaoDcgmngEi3JS4ASlTnL6zvrxbyqU7Z0QNLM8k/mtb2Pi4bT50hKCHSP'+
    'ZR72Pz6uaVRhfxSIWIDs7+Q4n8+706k+Db8K/wkUOwTrypSJqQAV2KzAVJBoiPSCpEAkikCK'+
    'rQKTm5NAohPCZLMv0AAVGFZgGkgsROpkLRaRaIhE0Yet4eVyeUQpAhdvcnhYFd5IBahAlwJT'+
    'QLIFIqW0Nhqx0YdEHTog8dIwKulqeyamAtMU2AySGRAptfGGNRUgF1PZU5L2eVlymlI0RAWo'+
    'QKgADJIKjDKBWveWWICUaz3DGSmRXmLTpfQhIikimCzL1bbGx+Px65I35Cq/y3WdVm4qv9nr'+
    '0dAty0vnU6OxJV/9vVVer0Uz217Zo3oi/SXSArmODnmjOuo2yTRE6qHTSNk9P4h8I0ub5Y+2'+
    'ldaq1ye89JGNKK3NP2q7Jkg8YHgCjUCkOsGyb2UNkhqJlD0tZT+LvEsa2eti77FL1guw1qDw'+
    'GsiK1Or0kaNYKLXykvTRfbYcWb7lN+3c3mcPsr2d2wOvwHaWjq1yat2ieqMw8bRvXfN8ywNb'+
    'D/SzBwvaqTOfR+qEpLF1SkHyaohokJTJU728q+HhwWTZNFfXgMukq95Alzkh2mG9RtV2s4gk'+
    '6sxyf+tJY5+OSIewQPI6u+5wUUfoycvaQJ5siH0UlrrjekBG8/L0jjqUbUMU9LosSETSCw7E'+
    '5xFIjDxAGyBZhgNRgyzLr9gKzXNla0RSJk8FCOW9QKF+X0ck+rvYEgiNgiSCw4ig2rHRzzad'+
    'dTiv83vtEUUJmf3Wb60OjXSqrFxoR880yQDaa18DBYXibJBIm2htRzSMyt9qsxG/D0HyHdFI'+
    'FSwe2kQQEcBYJxkFSRT+jwjagscItFBHbT3lkAgK7XhoCO6BCq2PLQuS50gkF7WZV07kGlI/'+
    'pC66XCO+2CprFMEhUctT34uOEUBBUgz27mBdP10ikJRUdRPaeo7kfL9+C1Zu+iZbrdN536Mh'+
    'SBYlZE8COzmXQcw+OVqdvAUSFGKtfDI46LprjaLrSF5eNGJtbx0G6Cggm1dC6ofON3l+osth'+
    'fSxKH2mIgiTKswdeUEQiE6mHw/NQZ3SSVSov/5vwJ08rTAo46qt+9peK61AommztdVimpwJU'+
    'AFegCyTFrAeTLRFJpeE6KtGbzerUifxLb4GI3QGbDWtwOZiSClCBEQWgyVYddWzdgOYVUkcl'+
    '6Bb5B17U/28IkpHm5z1UYI4CwD4SGc7o4cXnQKPj/zSt4mZDHAsNbUtWdzikaSnM36nA6xRo'+
    'gkSGM/oMkDJHsXVuxI9MKrT8f/k+HyUgS8bo5NbrZKRlKvC7FYBA8kqJ7BFuembaA4qUxUKk'+
    'dRRcBeL7j5CcVQbdJrNsUkMeIdnrS1/90Vv+7TXWm14yz49azDfDrZf7/OMhdWebdWwej1rk'+
    'UYu9vvQb/PCtZ7YWgZEjEpGICLEz64g+5rX9iD5q+H9p+PYzWxFIMA0VoAI/W4G3z5H8bHlY'+
    'OipABRAFCBJEJaahAlQgVYAgoYNQASqwWYF/o2XhCcA1FYIAAAAASUVORK5CYII=';

procedure TForm1.Button1Click(Sender: TObject);
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    DecodeBase64ToStream(stream, base64String);
    Image1.Picture.LoadFromStream(stream);
  finally
    stream.Free;
  end;
end;

Convert Base64 string to picture, 2

This procedure is from forum member KodeZwerg. 

procedure DisplayBase64(const ABase64String: AnsiString; const AImage: TImage);

He created a pretty easy to handle method that supports now all (?) formats that Lazarus Graphics offers. To name them: JPEG, PNG, GIF, BMP, ICO and TIFF. Full unit: 

unit uMain;

{$mode objfpc}{$H+}

interface

uses
  Classes , SysUtils , Forms , Controls , Graphics , Dialogs , ExtCtrls ,
  StdCtrls,
  Base64{, fpimage, fpreadpng};

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Image1: TImage;
    OpenDialog1: TOpenDialog;
    procedure Button1Click(Sender: TObject);
  private

  public

  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ Load a file into its corresponding image class }

function LoadJPGImage(const AFilename: string): TJPEGImage;
begin
  Result := TJPEGImage.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

function LoadPNGImage(const AFilename: string): TPortableNetworkGraphic;
begin
  Result := TPortableNetworkGraphic.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

function LoadGIFImage(const AFilename: string): TGIFImage;
begin
  Result := TGIFImage.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

function LoadBMPImage(const AFilename: string): TBitmap;
begin
  Result := TBitmap.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

function LoadICOImage(const AFilename: string): TIcon;
begin
  Result := TIcon.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

function LoadTIFFImage(const AFilename: string): TTiffImage;
begin
  Result := TTiffImage.Create;
  try
    Result.LoadFromFile(AFilename);
  finally
  end;
end;

{ convert image to base64 }

function JPGToBase64(const AImage: TJPEGImage): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

function PNGToBase64(const AImage: TPortableNetworkGraphic): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

function GIFToBase64(const AImage: TGIFImage): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

function BMPToBase64(const AImage: TBitmap): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

function ICOToBase64(const AImage: TIcon): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

function TIFFToBase64(const AImage: TTiffImage): AnsiString;
var
  stream: TMemoryStream;
  encodingStream: TBase64EncodingStream;
  output: TStringStream;
begin
  stream := TMemoryStream.Create;
  try
    AImage.SaveToStream(stream);
    stream.Position := 0;
    output := TStringStream.Create;
    try
      encodingStream := TBase64EncodingStream.Create(output);
      try
        encodingStream.CopyFrom(stream, stream.Size);
        encodingStream.Flush;
        Result := output.DataString;
      finally
        encodingStream.Free;
      end;
    finally
      output.Free;
    end;
  finally
    stream.Free;
  end;
end;

{ convert base64 to bytes }

function Base64ToBytes(const ABase64String: AnsiString): TBytes;
var
  decodedStream: TBase64DecodingStream;
begin
  decodedStream := TBase64DecodingStream.Create(TStringStream.Create(ABase64String));
  try
    SetLength(Result, decodedStream.Size);
    decodedStream.ReadBuffer(Result[0], decodedStream.Size);
  finally
    decodedStream.Free;
  end;
end;

{ determine the image format }

function GetBytesFormat(const AData: TBytes): Integer;
var
  signature: TBytes;
begin
  Result := -1;
  signature := Copy(AData, 0, 8);

  if CompareMem(@signature[0], @[$FF, $D8, $FF, $DB], 4) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$FF, $D8, $FF, $E0, $00, $10, $4A, $46], 8) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$49, $46, $00, $01], 4) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$FF, $D8, $FF, $EE], 4) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$FF, $D8, $FF, $E1], 4) and CompareMem(@signature[6], @[$45, $78], 2) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$69, $66, $00, $00], 4) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$FF, $D8, $FF, $E0], 4) then
    Result := 0 // JPEG
  else
  if CompareMem(@signature[0], @[$89, $50, $4E, $47, $0D, $0A, $1A, $0A], 8) then
    Result := 1 // PNG
  else
  if CompareMem(@signature[0], @[$47, $49, $46, $38, $37, $61], 6) then
    Result := 2 // GIF87a
  else
  if CompareMem(@signature[0], @[$47, $49, $46, $38, $39, $61], 6) then
    Result := 2 // GIF89a
  else
  if CompareMem(@signature[0], @[$42, $4D], 2) then
    Result := 3 // BMP
  else
  if CompareMem(@signature[0], @[$00, $00, $01, $00], 4) then
    Result := 4 // ICO
  else
  if CompareMem(@signature[0], @[$49, $49, $2A, $00], 4) then
    Result := 5 // TIF
  else
  if CompareMem(@signature[0], @[$4D, $4D, $00, $2A], 4) then
    Result := 5 // TIFF
  ;
end;

{ convert the bytes into the corresponding image class }

function Base64ToJPG(const AData: TBytes): TJPEGImage;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TJPEGImage.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

function Base64ToPNG(const AData: TBytes): TPortableNetworkGraphic;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TPortableNetworkGraphic.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

function Base64ToGIF(const AData: TBytes): TGIFImage;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TGIFImage.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

function Base64ToBMP(const AData: TBytes): TBitmap;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TBitmap.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

function Base64ToICO(const AData: TBytes): TIcon;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TIcon.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

function Base64ToTIFF(const AData: TBytes): TTiffImage;
var
  stream: TMemoryStream;
begin
  stream := TMemoryStream.Create;
  try
    stream.WriteBuffer(AData[0], Length(AData));
    stream.Position := 0;
    Result := TTiffImage.Create;
    try
      Result.LoadFromStream(stream);
    finally
    end;
  finally
    stream.Free;
  end;
end;

{ analyze and display a found image format into a TImage }

procedure DisplayBase64(const ABase64String: AnsiString; const AImage: TImage);
var
  bytes: TBytes;
  jpg: TJPEGImage;
  png: TPortableNetworkGraphic;
  gif: TGIFImage;
  bmp: TBitmap;
  ico: TIcon;
  tif: TTiffImage;
begin
  bytes := Base64ToBytes(ABase64String);
  AImage.Picture.Clear;
  case GetBytesFormat(bytes) of
    0: begin jpg := Base64ToJPG(bytes); AImage.Picture.Assign(jpg); jpg.Free; end;
    1: begin png := Base64ToPNG(bytes); AImage.Picture.Assign(png); png.Free; end;
    2: begin gif := Base64ToGIF(bytes); AImage.Picture.Assign(gif); gif.Free; end;
    3: begin bmp := Base64ToBMP(bytes); AImage.Picture.Assign(bmp); bmp.Free; end;
    4: begin ico := Base64ToICO(bytes); AImage.Picture.Assign(ico); ico.Free; end;
    5: begin tif := Base64ToTIFF(bytes); AImage.Picture.Assign(tif); tif.Free; end;
  end;
end;

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
var
  { all supported formats }
  jpg: TJPEGImage;
  png: TPortableNetworkGraphic;
  gif: TGIFImage;
  bmp: TBitmap;
  ico: TIcon;
  tif: TTiffImage;
  { the base64 encoded data }
  base64String: AnsiString;
  ext: string;
begin
  base64String := '';
  if OpenDialog1.Execute then
    begin
      ext := LowerCase(ExtractFileExt(OpenDialog1.FileName));
      if ext = '.jpg' then
        begin
          jpg := LoadJPGImage(OpenDialog1.FileName);
          base64String := JPGToBase64(jpg);
          jpg.Free;
        end
      else
      if ext = '.jpeg' then
        begin
          jpg := LoadJPGImage(OpenDialog1.FileName);
          base64String := JPGToBase64(jpg);
          jpg.Free;
        end
      else
      if ext = '.jfif' then
        begin
          jpg := LoadJPGImage(OpenDialog1.FileName);
          base64String := JPGToBase64(jpg);
          jpg.Free;
        end
      else
      if ext = '.png' then
        begin
          png := LoadPNGImage(OpenDialog1.FileName);
          base64String := PNGToBase64(png);
          png.Free;
        end
      else
      if ext = '.gif' then
        begin
          gif := LoadGIFImage(OpenDialog1.FileName);
          base64String := GIFToBase64(gif);
          gif.Free;
        end
      else
      if ext = '.bmp' then
        begin
          bmp := LoadBMPImage(OpenDialog1.FileName);
          base64String := BMPToBase64(bmp);
          bmp.Free;
        end
      else
      if ext = '.ico' then
        begin
          ico := LoadICOImage(OpenDialog1.FileName);
          base64String := ICOToBase64(ico);
          ico.Free;
        end
      else
      if ext = '.tif' then
        begin
          tif := LoadTIFFImage(OpenDialog1.FileName);
          base64String := TIFFToBase64(tif);
          tif.Free;
        end
      else
      if ext = '.tiff' then
        begin
          tif := LoadTIFFImage(OpenDialog1.FileName);
          base64String := TIFFToBase64(tif);
          tif.Free;
        end;
      if base64String <> '' then
        DisplayBase64(base64String, Image1);
    end;
end;

end.

Convert Base64 string to picture, using BGRABitmap

This unit is from forum member KodeZwerg. You must install the BGRABitmap component. 

unit ubase64image;

{$mode ObjFPC}{$H+}

interface

uses
  Classes, SysUtils, Graphics, ExtCtrls,
  Base64,
  BGRABitmap, BGRABitmapTypes, BGRAGraphics, BGRASVG, BGRAOpenRaster, BGRAPhoxo, BGRAPaintNet;

function FileToStream(const AFilename: string): TStream;
function StreamToBase64(const AStream: TStream): AnsiString;
function Base64ToStream(const ABase64String: AnsiString): TStream;
procedure AssignBase64ToImage(const ABase64String: AnsiString; const AImage: TImage; const AFastMode: Boolean = False);

implementation

function FileToStream(const AFilename: string): TStream;
var
  FileStream: TFileStream;
begin
  FileStream := TFileStream.Create(AFileName, fmOpenRead or fmShareDenyWrite);
  try
    Result := TMemoryStream.Create;
    try
      Result.CopyFrom(FileStream, FileStream.Size);
    finally
      Result.Position := 0;
    end;
  finally
    FileStream.Free;
  end;
end;

function StreamToBase64(const AStream: TStream): string;
var
  EncodedStream: TStringStream;
  Encoder: TBase64EncodingStream;
begin
  EncodedStream := TStringStream.Create('');
  Encoder := TBase64EncodingStream.Create(EncodedStream);
  try
    AStream.Position := 0;
    Encoder.CopyFrom(AStream, AStream.Size);
    Encoder.Flush;
    Result := EncodedStream.DataString;
    AStream.Position := 0;
  finally
    Encoder.Free;
    EncodedStream.Free;
  end;
end;

function Base64ToStream(const ABase64String: AnsiString): TStream;
var
  DecodedStream: TBase64DecodingStream;
  Base64Stream: TStringStream;
begin
  Base64Stream := TStringStream.Create(ABase64String);
  try
    DecodedStream := TBase64DecodingStream.Create(base64stream);
    try
      Result := TMemoryStream.Create;
      try
        Result.CopyFrom(DecodedStream, DecodedStream.Size);
      finally
        Result.Position := 0;
      end;
    finally
      DecodedStream.Free;
    end;
  finally
    Base64Stream.Free;
  end;
end;

function BGRABitmapToPNGStream(const ABGRABitmap: TBGRABitmap): TStream;
begin
  Result := TMemoryStream.Create;
  try
    ABGRABitmap.SaveToStreamAsPng(Result);
  finally
    Result.Position := 0;
  end;
end;

function BGRABitmapToBitmap(const ABGRABitmap: TBGRABitmap): TBitmap;
begin
  Result := TBitmap.Create;
  try
    Result.PixelFormat := ABGRABitmap.Bitmap.PixelFormat;
    Result.Transparent := ABGRABitmap.HasTransparentPixels or ABGRABitmap.HasSemiTransparentPixels;
    Result.SetSize(ABGRABitmap.Width, ABGRABitmap.Height);
    Result.Canvas.Lock;
    try
      Result.Canvas.Draw(0, 0, ABGRABitmap.Bitmap);
    finally
      Result.Canvas.Unlock;
    end;
  finally
  end;
end;

procedure AssignBase64ToImage(const ABase64String: AnsiString; const AImage: TImage;
  const AFastMode: Boolean = False);
var
  BGRABitmap: TBGRABitmap;
  Stream: TStream;
  bmp: TBitmap;
begin
  AImage.Picture.Clear;
  Stream := Base64ToStream(ABase64String);
  if (DetectFileFormat(Stream) <> ifUnknown) then
    begin
      BGRABitmap := TBGRABitmap.Create;
      try
        try
          BGRABitmap.LoadFromStream(Stream);
        finally
          Stream.Free;
        end;
        if AFastMode then
          begin
            bmp := BGRABitmapToBitmap(BGRABitmap);
            try
              AImage.Transparent := bmp.Transparent;
              AImage.Picture.Assign(bmp);
            finally
              bmp.Free;
            end;
          end
        else
          begin
            Stream := BGRABitmapToPNGStream(BGRABitmap);
            try
              AImage.Transparent := BGRABitmap.HasTransparentPixels or BGRABitmap.HasSemiTransparentPixels;
              AImage.Picture.PNG.LoadFromStream(Stream);
            finally
              Stream.Free;
            end;
          end;
      finally
        BGRABitmap.Free;
      end;
    end
    else
      Stream.Free;
end;

initialization
  BGRASVG.RegisterSvgFormat;
  BGRAOpenRaster.RegisterOpenRasterFormat;
  BGRAPhoxo.RegisterPhoxoFormat;
  BGRAPaintNet.RegisterPaintNetFormat;
end.
Retrieved from "http://wiki.freepascal.org/index.php?title=Base64&oldid=157105"