Base64
From Lazarus wiki
Revision as of 15:48, 14 August 2023 by Alextpp (talk | contribs) (→Convert Base64 string to picture)
Various code example to handle Base64 encoded strings.
Convert Base64 string to picture
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.