.net - C# - logic for splitting the PDF / TIFF file when there is a blank page detected

Question

I want to have a better logic for getting the splitter (markers) when blank page is detected and remove blanks pages and return it to UI showing the splitters.

Scenario 1 :

1. User upload 1 file (5) page => Page 1 - blank, Page 2 - not blank, Page 3 - Blank, Page 4 - not blank, Page 5 - blank
2. Detect blank pages and create splitters.
3. Remove blank pages (P1, P3, P5)
4. create new file which will have only not blank pages. (P2, P4)
5. Return the markers to UI
6. Final result for splitters should be : 0, 1

Scenario 2 :

1. User upload 1 file (9) page => P1 P2 - blank, P3 P4 not blank, P5 P6 - Blank, P7 - not blank, P8 P9 - blank
2. Detect blank pages and create splitters.
3. Remove blank pages (P1, P2, P5, P7, P8, P9)
4. create new file which will have only not blank pages. (P3, P4, P7)
5. Return the markers to UI
6. Final result for splitters should be : 0, 2

PS: 0 in the splitters will always be there as it indicates the index where new file starts.

this is what I have for now and its working fine BUT i would like to have a better logic for the same.

 public List<int> GetMarkers(string mergedFile, SplitAndMergeFilesRequestDto optionsDto)
    {
        //improvements - remove invalid markers if higher than page count
        //improvements - deal with blank pages only (1,2,3 blank pages)
        //improvements - write tests

        var markersToReturn = new List<int>();
        var frameCount = RegisteredDecoders.GetImageInfo(mergedFile).FrameCount;

        for (int i = 0; i < frameCount; i++)
        {
            bool blankPageDetected = false;
            string tempFileName = GetFullPathForMergedFile();

            for (var frameIndex = 0; frameIndex < RegisteredDecoders.GetImageInfo(mergedFile).FrameCount; frameIndex++)
            {
                using (Stream readStream = new FileStream(mergedFile, FileMode.Open, FileAccess.Read))
                {
                    using (var img = new AtalaImage(readStream, frameIndex, null))
                    {
                        Log.Information($"Checking for BlankPage. FrameIndex: {frameIndex}");

                        if (IsBlankPage(img))
                        {
                            readStream.Seek(0, SeekOrigin.Begin);
                            var tiffDocument = new TiffDocument(readStream);
                            tiffDocument.Pages.RemoveAt(frameIndex);
                            tiffDocument.Save(tempFileName);

                            if (!markersToReturn.Contains(frameIndex))
                            {
                                markersToReturn.Add(frameIndex);
                            }

                            blankPageDetected = true;
                            Log.Information($"BlankPage found at FrameIndex: {frameIndex}");
                            break;
                        }
                    }
                }
            }

            if (blankPageDetected)
            {
                File.Copy(tempFileName, mergedFile, true);
                File.Delete(tempFileName);
            }
            else
            {
                break;
            }
        }

        Log.ForContext<BlankPageStrategyCalculateMarkersService>()
            .Information("SplitAndMerge - Created SplitMarkers: {@SplitMarkers}", markersToReturn);

        if (!markersToReturn.Contains(0))
        {
            markersToReturn.Insert(0, 0);
        }

        return markersToReturn;
    }

question from:https://stackoverflow.com/questions/65517007/c-sharp-logic-for-splitting-the-pdf-tiff-file-when-there-is-a-blank-page-det

Answer 1

Waitting for answers