How to display picture(jpg) with TDBImage from TBlobField? - delphi

Question

I want to display image from database that was set to blobdata type.
But when i pair with TDBImage show error
anyone can help?

Answer 1

I have been using this code to load any kind of image from Database.
uses
Vcl.Graphics, PNGImage, JPEG;
function GetHeader(const AFile: string; const AByteCount: integer): string;
const
HEADER_STR = '%s_HEADER: array [0 .. %d] of byte = (%s)';
var
_HeaderStream: TMemoryStream;
_FileStream: TMemoryStream;
_Buf: integer;
_Ext: string;
_FullByteStrArr: string;
_ByteStr: string;
i: integer;
begin
Result := '';
if not FileExists(AFile) then
Exit;
_HeaderStream := TMemoryStream.Create;
_FileStream := TMemoryStream.Create;
try
_FileStream.LoadFromFile(AFile);
_FileStream.Position := 0;
_HeaderStream.CopyFrom(_FileStream, 5);
if _HeaderStream.Size > 4 then
begin
_HeaderStream.Position := 0;
_ByteStr := '';
_FullByteStrArr := '';
for i := 0 to AByteCount do
begin
_HeaderStream.Read(_Buf, 1);
_ByteStr := IntToHex(_Buf, 2);
_FullByteStrArr := _FullByteStrArr + ', $' +
Copy(_ByteStr, Length(_ByteStr) - 1, 2);
end;
_FullByteStrArr := Copy(_FullByteStrArr, 3, Length(_FullByteStrArr));
_Ext := UpperCase(ExtractFileExt(AFile));
_Ext := Copy(_Ext, 2, Length(_Ext));
Result := Format(HEADER_STR, [_Ext, AByteCount, _FullByteStrArr]);
end;
finally
FreeAndNil(_FileStream);
FreeAndNil(_HeaderStream);
end;
end;
function GetImageFromBlob(const ABlobField: TBlobField): TGraphic;
CONST
JPG_HEADER: array [0 .. 2] of byte = ($FF, $D8, $FF);
GIF_HEADER: array [0 .. 2] of byte = ($47, $49, $46);
BMP_HEADER: array [0 .. 1] of byte = ($42, $4D);
PNG_HEADER: array [0 .. 3] of byte = ($89, $50, $4E, $47);
TIF_HEADER: array [0 .. 2] of byte = ($49, $49, $2A);
TIF_HEADER2: array [0 .. 2] of byte = (77, 77, 00);
PCX_HEADER: array [0 .. 2] of byte = (10, 5, 1);
var
_HeaderStream: TMemoryStream;
_ImgStream: TMemoryStream;
_GraphicClassName: string;
_GraphicClass: TGraphicClass;
begin
Result := nil;
_HeaderStream := TMemoryStream.Create;
_ImgStream := TMemoryStream.Create;
try
ABlobField.SaveToStream(_ImgStream);
_ImgStream.Position := 0;
_HeaderStream.CopyFrom(_ImgStream, 5);
if _HeaderStream.Size > 4 then
begin
if CompareMem(_HeaderStream.Memory, #JPG_HEADER, SizeOf(JPG_HEADER)) then
_GraphicClassName := 'TJPEGImage'
else if CompareMem(_HeaderStream.Memory, #GIF_HEADER, SizeOf(GIF_HEADER))
then
_GraphicClassName := 'TGIFImage'
else if CompareMem(_HeaderStream.Memory, #PNG_HEADER, SizeOf(PNG_HEADER))
then
_GraphicClassName := 'TPNGImage'
else if CompareMem(_HeaderStream.Memory, #BMP_HEADER, SizeOf(BMP_HEADER))
then
_GraphicClassName := 'TBitmap'
else if CompareMem(_HeaderStream.Memory, #TIF_HEADER, SizeOf(TIF_HEADER))
then
_GraphicClassName := 'TWICImage'
else if CompareMem(_HeaderStream.Memory, #TIF_HEADER2, SizeOf(TIF_HEADER2))
then
_GraphicClassName := 'TWICImage'
else if CompareMem(_HeaderStream.Memory, #PCX_HEADER, SizeOf(PCX_HEADER))
then
_GraphicClassName := 'PCXImage';
RegisterClasses([TIcon, TMetafile, TBitmap, TJPEGImage, TPngImage,
TWICImage]);
_GraphicClass := TGraphicClass(FindClass(_GraphicClassName));
if (_GraphicClass <> nil) then
begin
Result := _GraphicClass.Create; // Create appropriate graphic class
_ImgStream.Position := 0;
Result.LoadFromStream(_ImgStream);
end;
end;
finally
FreeAndNil(_ImgStream);
FreeAndNil(_HeaderStream);
end;
end;
{ --- Usage --- }
procedure TForm1.BitBtn5Click(Sender: TObject);
begin
qImage.Close;
qImage.ParamByName('prm_id').Value := Edit2.Text;
qImage.Open;
Image1.Picture.Assign(GetImageFromBlob(qImageany_kind_image));
Image1.Picture.SaveToFile('C:\Users\Edijs\Desktop\test.' +
GraphicExtension(TGraphicClass
(GetClass(Image1.Picture.Graphic.ClassName))));
end;

Answer 2

In your case you can use just the *.bmp files , to use *.jpeg files
You must use JPEG unit :
Uses
JPEG;