fpexif: Fix detection of EXIF structure if a JFIF extension APP0 marker segment is in file (JFXX). Extract JFXX thumbnail.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7194 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/fpexif/examples/file_renamer/frmain.pas

@@ -179,17 +179,17 @@ begin
   imgInfo := TImgInfo.Create;
   try
     imgInfo.LoadFromFile(ShellTreeView.Path + Item.Caption);
-    if not (imgInfo.HasExif and imgInfo.HasThumbnail) then begin
+    if not (imgInfo.HasThumbnail) then begin
       ThumbImg.Picture.LoadFromFile(ShellTreeView.Path + Item.Caption);
       exit;
     end;
 
     ms := TMemoryStream.Create;
     try
-      imgInfo.ExifData.SaveThumbnailToStream(ms);
+      imgInfo.SaveThumbnailToStream(ms);
       if ms.Size > 0 then begin
         ms.Position := 0;
-        ThumbImg.Picture.LoadfromStream(ms);
+        ThumbImg.Picture.LoadFromStream(ms);
       end else
         ThumbImg.Picture.Clear;
     finally

components/fpexif/examples/metadata_viewer/MetadataViewer.lpi

@@ -66,6 +66,11 @@
       <Debugging>
         <UseExternalDbgSyms Value="True"/>
       </Debugging>
+      <Options>
+        <Win32>
+          <GraphicApplication Value="True"/>
+        </Win32>
+      </Options>
     </Linking>
   </CompilerOptions>
   <Debugging>

components/fpexif/examples/metadata_viewer/mdvmain.pas

@@ -320,10 +320,10 @@ begin
         end;
       end;
 
-      if FImgInfo.HasThumbnail and Assigned(FImgInfo.ExifData) then begin
+      if FImgInfo.HasThumbnail then begin
         ms := TMemoryStream.Create;
         try
-          FImgInfo.ExifData.SaveThumbnailToStream(ms);
+          FImgInfo.SaveThumbnailToStream(ms);
           ms.Position := 0;
           PreviewImage.Picture.LoadFromStream(ms);
           RotateBitmap(PreviewImage.Picture.Bitmap, FImageOrientation);

components/fpexif/examples/simple_demo/ExifSimpleDemo.lpi

@@ -1,11 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <CONFIG>
   <ProjectOptions>
-    <Version Value="11"/>
+    <Version Value="12"/>
     <PathDelim Value="\"/>
     <General>
+      <Flags>
+        <CompatibilityMode Value="True"/>
+      </Flags>
       <SessionStorage Value="InProjectDir"/>
-      <MainUnit Value="0"/>
       <Title Value="ExifSimpleDemo"/>
       <ResourceType Value="res"/>
       <UseXPManifest Value="True"/>

components/fpexif/examples/simple_demo/sdmain.lfm

@@ -130,7 +130,7 @@ object MainForm: TMainForm
       Left = 312
       Height = 19
       Top = 10
-      Width = 128
+      Width = 127
       BorderSpacing.Left = 8
       Caption = 'Truncate binary tags'
       Checked = True
@@ -143,7 +143,7 @@ object MainForm: TMainForm
       AnchorSideLeft.Side = asrBottom
       AnchorSideTop.Control = CbVerbosity
       AnchorSideTop.Side = asrCenter
-      Left = 448
+      Left = 447
       Height = 19
       Top = 10
       Width = 123
@@ -233,7 +233,7 @@ object MainForm: TMainForm
     Left = 620
     Height = 15
     Top = 347
-    Width = 19
+    Width = 18
     Anchors = [akLeft, akBottom]
     BorderSpacing.Bottom = 4
     Caption = 'Tag'

components/fpexif/examples/simple_demo/sdmain.pas

@@ -308,12 +308,16 @@ procedure TMainForm.LoadThumbnail;
 var
   ms: TMemoryStream;
 begin
-  if (FImgInfo.ExifData = nil) or (not FImgInfo.Exifdata.HasThumbnail) then
+  if not FImgInfo.HasThumbnail then
     exit;
 
+  //if (FImgInfo.ExifData = nil) or (not FImgInfo.Exifdata.HasThumbnail) then
+  //  exit;
+
   ms := TMemoryStream.Create;
   try
-    FImgInfo.ExifData.SaveThumbnailToStream(ms);
+    FImgInfo.SaveThumbnailToStream(ms);
+//    FImgInfo.ExifData.SaveThumbnailToStream(ms);
     ms.Position := 0;
     Thumbnail.Picture.LoadfromStream(ms);
   finally

components/fpexif/fpemetadata.pas

@@ -58,6 +58,7 @@ type
     FWarnings: TStrings;
     FMetadataKinds: TMetadataKinds;
     FHeaderSegment: TBytes;
+    FJFXXThumbnail: TBytes;
     FComment: String;
   private
     FExifData: TExifData;
@@ -80,6 +81,7 @@ type
     procedure LoadFromStream(AStream: TStream);
     procedure Save;
     procedure SaveToFile(const AFileName: String; AImgFile: String = '');
+    procedure SaveThumbnailToStream(AStream: TStream);
 
     function CreateExifData(ABigEndian: Boolean = false): TExifData;
     function CreateIptcData: TIptcData;
@@ -132,6 +134,13 @@ type
   end;
   PJpegJFIFSegment = ^TJpegJFIFSegment;
 
+  TJpegJFXXSegment = packed record
+    Identifier: packed array[0..4] of AnsiChar;   // 'JFXX'#0
+    ThumbnailFormat: byte;   // 10: JPEG, 11: 1 byte-per-pixel palettized, 12: 3 byte-per-pixel RGB
+  end;
+  // ThumbnailData are following
+  PJpegJFXXSegment = ^TJpegJFXXSegment;
+
   TJpegSOF0Segment = packed record
     DataPrecision: Byte;
     ImageHeight: Word;
@@ -331,7 +340,8 @@ end;
 
 function TImgInfo.HasThumbnail: boolean;
 begin
-  Result := (FExifData <> nil) and FExifData.HasThumbnail;
+  Result := ((FExifData <> nil) and FExifData.HasThumbnail)
+         or (Length(FJFXXThumbnail) > 0);
 end;
 
 function TImgInfo.HasWarnings: boolean;
@@ -433,6 +443,9 @@ begin
 end;
 
 procedure TImgInfo.ReadJpeg(AStream: TStream);
+const
+  sJFIF: String[5] = 'JFIF'#0;
+  sJFXX: String[5] = 'JFXX'#0;
 var
   marker: Byte;
   size: Word;
@@ -441,6 +454,7 @@ var
   buf: TBytes;
   reader: TBasicMetadataReader;
   bigEndian: Boolean;
+  hdr: TBytes;
  {$IFNDEF FPC}
   sa: ansistring;
  {$ENDIF}
@@ -517,17 +531,32 @@ begin
         end;
       M_JFIF:
         begin
+          SetLength(hdr, size);
+          AStream.Read(hdr[0], size);
+          with PJpegJFIFSegment(@hdr[0])^ do begin
+            if CompareMem(@Identifier[0], @sJFIF[1], Length(sJFIF)) then
+            begin
+              // JFIF APP0 marker segment
               SetLength(FHeaderSegment, size);
-          AStream.Read(FHeaderSegment[0], size);
+              Move(hdr[0], FHeaderSegment[0], size);
-          with PJpegJFIFSegment(@FHeaderSegment[0])^ do begin
-            if not (
-              (Identifier[0]='J') and (Identifier[1]='F') and
-              (Identifier[2]='I') and (Identifier[3]='F') and
-              (Identifier[4]=#0) )
-            then
-              exit;
               if (JFIFVersion[0] <> 1) then
                 exit;
+            end else
+            if CompareMem(@Identifier[0], @sJFXX[1], Length(sJFXX)) then
+            begin
+              // JFXX extension APP0 marker segment  (optional)
+              // alternative location of a thumbnail image:
+              // https://en.wikipedia.org/wiki/JPEG_File_Interchange_Format#JFIF_extension_APP0_marker_segment
+              {
+              // --- not supported at the moment.
+              SetLength(FJFXXHeaderSegment, size);
+              Move(hdr[0], FJFXXHeaderSegment[0], size);
+              }
+              // --- not working... not a valid jpeg structure.
+
+              SetLength(FJFXXThumbnail, size - SizeOf(TJpegJFXXSegment)); //(AStream.Position - p));
+              Move(hdr[SizeOf(TJpegJFXXSegment)], FJFXXThumbnail[0], Length(FJFXXThumbnail));
+            end;
           end;
         end;
       M_SOF0:
@@ -573,6 +602,15 @@ begin
   SaveToFile(FFileName);
 end;
 
+procedure TImgInfo.SaveThumbnailToStream(AStream: TStream);
+begin
+  if (FExifData <> nil) and ExifData.HasThumbnail then
+    FExifData.SaveThumbnailToStream(AStream)
+  else
+  if Length(FJFXXThumbnail) > 0 then
+    AStream.Write(FJFXXThumbnail[0], Length(FJFXXThumbnail));
+end;
+
 procedure TImgInfo.SaveToFile(const AFileName: String; AImgFile: String = '');
 var
   ms: TMemoryStream;