Writing PNG images using streams fails in V2.0 when targeting .ods format.

[Russ]

There is an issue when writing PNG images to worksheets using streams in V2.0 that didn't manifest in V1.16:

When PNG image(s) are written to a sheet using a stream through the TsWorkSheet.WriteImage() and the resultant workbook is then written to disk in .ods format, when attempting to open the document in Libre Office Calc, a read error "Format error discovered in the file in sub-document content.xml at 1,4468(row,col)" is thrown. When the image is written using the File version of the TsWorksheet.WriteImage() function where the image is loaded from a PNG file, then everything works. There are no problems with .xlsx format.

The .ods archives were unpacked and the problems found are the following:

• In the Picture directory there are no images.
• In content.xml the field <draw:image xlink:href="Pictures/" has no images listed.
• manifest.xml has the same problem.

In addition, if the user (me ) uses the same stream to load multiple images and forgets to clear the stream between loading images, then the application hangs. There is a fix that stops the app from hanging, but won't stop the wrong image from being loaded.
   
A patch is attached.

The test project:

Code: Pascal  [Select][+][-]

1. program project1;
2. uses
3.   SysUtils, Classes, Graphics, LCLIntf, fpSpreadsheet, fpsTypes, fpsallformats;
4. var
5.   wbook: TsWorkbook;
6.   wsheet: TsWorksheet;
7.   image1: TPortableNetworkGraphic;
8.   image2: TPortableNetworkGraphic;
9.   astream: TMemoryStream;
10.  
11. begin
12.   wbook := TsWorkbook.create;
13.   image1 := TPortableNetworkGraphic.Create;
14.   image2 := TPortableNetworkGraphic.Create;
15.   astream:= TMemoryStream.Create;
16.   try
17.     (* In the target application the image is created by the app and not loaded from a file. *)
18.     image1.LoadFromFile('Image1.png');
19.     image2.LoadFromFile('Image2.png');
20.  
21.     (* Writing the image to the sheet directly from a file works for both .ods and .xlsx formats. *)
22.     //wsheet := wbook.AddWorksheet('Image1');
23.     //wsheet.WriteImage(0, 0, 'Image1.png');
24.     //wsheet := wbook.AddWorksheet('Image2');
25.     //wsheet.WriteImage(0, 0, 'Image2.png');
26.     //wbook.WriteToFile('Test1_WriteImage(File).xlsx', true);
27.     //wbook.WriteToFile('Test1_WriteImage(File).ods', true);
28.     //wbook.clear;
29.  
30.     (* Copying a spreadsheet containing the image from excel to calc format works. *)
31.     //wbook.ReadFromFile('Test1_WriteImage(File).xlsx');
32.     //wbook.WriteToFile('Test2_SpreadsheetCopy.ods', true);
33.  
34.     (*
35.       Writing the image to the sheet using a stream works on V1.16, but not on V2.00.
36.       Attempting to open image_03.ods in Calc results in an error:
37.       Format error discovered in the file in sub-document content.xml at 1,4466(row,col).
38.     *)
39.     wbook.Clear;
40.     wsheet := wbook.AddWorksheet('Image 1');
41.     image1.SaveToStream(astream);
42.     wsheet.WriteImage(0, 0, astream, 1.0, 1.0);
43.     wsheet := wbook.AddWorksheet('Image 2');
44.  
45.     astream.Clear; // If this was forgotten, the application used to hang - now loads Image1 for Image2.
46.     image2.SaveToStream(astream);
47.     wsheet.WriteImage(0, 0, astream, 1.0, 1.0);
48.     wbook.WriteToFile('Test3_WriteImage(Stream).xlsx', true);
49.     wbook.WriteToFile('Test3_WriteImage_01(Stream).ods', true);
50.  
51.     OpenDocument('Test3_WriteImage_01(Stream).ods');
52.  
53.   finally
54.     wbook.Free;
55.     image1.Free;
56.     image2.Free;
57.     astream.Free;
58.   end;
59. end.

[wp]

Thanks for analyzing the situation and providing a patch. Applied to ccr-svn.