Deleting slides from presentation Leave feedback

There are many presentation document formats — PPT, PPTX, ODP and many more. They all have one common thing — the slides. Each presentation document has one or more slides, and these slides may be treated as containers of different content: text, geometric shapes, raster and vector images, animations, video, audio, comments, embedded objects and many more. The GroupDocs.Editor from its beginning had an ability to edit presentations, but only on a per-slide basis: a user can edit only the content of one slide at a time.

Initially, when the content of the slide was edited, it was only possible to save it as a new one-slide presentation. In particular, the pipeline was the next: user loads a presentation to the Editor class, selects the slide to edit with help of PresentationEditOptions, obtains EditableDocument, edits the HTML-content of the slide, saves this content back to the EditableDocument, and finally generates a new presentation file with one slide using the Editor.Save() method.

After release of the version 20.4, when the new SlideNumber property was introduced, this pipeline was expanded — it became possible to insert an edited slide into the original presentation using two ways:

by replacing the original slide, that was initially set for editing, onto its edited version,
and by putting the edited slide to “co-exist” together with its original version before edit.

This mechanism is explained in detail in a separate article.

Starting from the version 25.11, it is possible not only to edit and replace slides in the resultant presentation, but also delete them from it. The PresentationSaveOptions class now contains one new property — a int[] SlideNumbersToDelete, which basically is an array of integers, where each integer represents a number of one slide that should be removed. Slide numbers here are 1-based, so the 1st slide has number 1, not 0.

With the new slides removal feature the GroupDocs.Editor performs the next algorithm during saving the presentation:

User edits a content of the slide in the WYSIWYG-editor, passes the edited content to the instance of the EditableDocument class using one of its static methods, creates and adjusts the PresentationSaveOptions, and passes the EditableDocument instance, PresentationSaveOptions instance, and output stream or file path for writing to the Editor.Save() method.
If the value of the SlideNumber property in the PresentationSaveOptions instance is set to the default value 0, the GroupDocs.Editor generates a new presentation with one slide inside it. The SlideNumbersToDelete property is ignored regardless of its value.
If the value of the SlideNumber property in the PresentationSaveOptions instance has some non-zero value, the GroupDocs.Editor treats it as a command to insert the edited slide into the original presentation.
Depending on the InsertAsNewSlide property, the GroupDocs.Editor replaces old slide, specified by the value of the SlideNumber property, on the new one, taken from the EditableDocument instance, or puts the new slide to be placed among existing slides without replacing any of them.
Finally, when all slide insertions and rearrangements are finished, the GroupDocs.Editor reads the value of the SlideNumbersToDelete property, iterates over all numbers and removes specified slides from the presentation.
The final presentation, with updated and deleted slides, is written to the output stream or file.

Example below shows full roundtrip of input PPT file: presentation with 21 slides inside is loaded, its second slide is converted to the EditableDocument, then HTML-markup is emitted from the EditableDocument instance, modified, and then edited HTML-markup is converted back to the another EditableDocument instance. From this point two instances of the PresentationSaveOptions class are created — one is intended for generating a first version of an output presentation with a new slide and without deletion and finally it has 22 slides in total (21 original + 1 edited). The second PresentationSaveOptions instance has the SlideNumbersToDelete property set to remove the first and last slides, so the 2nd version of an output presentation will have 20 slides in total (19 original + 1 edited).

Input PPT as well as two versions of the output PPTX files may be downloaded here:

using GroupDocs.Editor;
using GroupDocs.Editor.Formats;
using GroupDocs.Editor.Options;
// ...

// Load input presentation to the Editor and specify loading options
using (Editor editor = new Editor("Presentations-Tips.ppt", new PresentationLoadOptions()))
{
    // Prepare edit options and set 2nd slide to edit
    PresentationEditOptions editOptions = new PresentationEditOptions();
    editOptions.ShowHiddenSlides = true;
    editOptions.SlideNumber = 1;//2nd slide to edit, here SlideNumber is 0-based due to historical reasons

    //generate EditableDocument with original content of 2nd slide
    using (EditableDocument slide2OpenedForEdit = editor.Edit(editOptions))
    {
        // Get the HTML-markup from the EditableDocument with original content
        string originalHtmlContentOf2ndSlide = slide2OpenedForEdit.GetEmbeddedHtml();

        //emulate HTML content editing in WYSIWYG-editor in browser or somewhere else
        string editedHtmlContentOf2ndSlide = originalHtmlContentOf2ndSlide.Replace("Tips to be Covered", "Edited tips on 2nd slide");

        //generate EditableDocument with edited content of 2nd slide
        using (EditableDocument slide2AfterEdit = EditableDocument.FromMarkup(editedHtmlContentOf2ndSlide))
        {
            //prepare save options without deletions
            PresentationSaveOptions saveOptionsWithoutDelete = new PresentationSaveOptions(PresentationFormats.Pptx);
            // let it be the 2nd slide...
            saveOptionsWithoutDelete.SlideNumber = 2;//here SlideNumber is 1-based
            //... and we also save the original 2nd slide, which is pushed to the 3rd position
            saveOptionsWithoutDelete.InsertAsNewSlide = true;

            // So now the presentation must have 22 slides, not 21. Save it to file
            editor.Save(slide2AfterEdit, "Output22Slides-without-delete.pptx", saveOptionsWithoutDelete);

            // Create another save options, with deletions at this time
            PresentationSaveOptions saveOptionsWithDelete = new PresentationSaveOptions(PresentationFormats.Pptx);
            // let the new slide will be 2nd for now, but after deleting it will became the 1st later
            saveOptionsWithDelete.SlideNumber = 2;

            //... and we also save the original 2nd slide, which will be next sibling to the newly inserted
            saveOptionsWithDelete.InsertAsNewSlide = true;

            // delete the 1st and last slide
            saveOptionsWithDelete.SlideNumbersToDelete = new int[2]
            {
                1,//1st slide
                22//last slide is 22, not 21, because we inserted the edited 2nd slide as the new slide instance, without rewriting the original 2nd slide
            };
            // Save it again to distinct file. Output PPTX should have 20 slides now.
            editor.Save(slide2AfterEdit, "Output20Slides-with-delete.pptx", saveOptionsWithDelete);
        }
    }
}

VB.NET

Imports GroupDocs.Editor
Imports GroupDocs.Editor.Formats
Imports GroupDocs.Editor.Options
' ...

' Load input presentation to the Editor and specify loading options
Using editor As New Editor("Presentations-Tips.ppt", New PresentationLoadOptions())
    ' Prepare edit options and set 2nd slide to edit
    Dim editOptions As New PresentationEditOptions
    editOptions.ShowHiddenSlides = True
    editOptions.SlideNumber = 1 '2nd slide to edit, here SlideNumber is 0-based due to historical reasons

    ' generate EditableDocument with original content of 2nd slide
    Using slide2OpenedForEdit As EditableDocument = editor.Edit(editOptions)
        ' Get the HTML-markup from the EditableDocument with original content
        Dim originalHtmlContentOf2ndSlide As String = slide2OpenedForEdit.GetEmbeddedHtml()

        ' emulate HTML content editing in WYSIWYG-editor in browser or somewhere else
        Dim editedHtmlContentOf2ndSlide As String = originalHtmlContentOf2ndSlide.Replace("Tips to be Covered", "Edited tips on 2nd slide")

        ' generate EditableDocument with edited content of 2nd slide
        Using slide2AfterEdit As EditableDocument = EditableDocument.FromMarkup(editedHtmlContentOf2ndSlide)
            ' prepare save options without deletions
            Dim saveOptionsWithoutDelete As New PresentationSaveOptions(PresentationFormats.Pptx)

            ' let it be the 2nd slide...
            saveOptionsWithoutDelete.SlideNumber = 2
            '... and we also save the original 2nd slide, which is pushed to the 3rd position
            saveOptionsWithoutDelete.InsertAsNewSlide = True

            ' So now the presentation must have 22 slides, not 21. Save it to file
            editor.Save(slide2AfterEdit, "Output22Slides-without-delete.pptx", saveOptionsWithoutDelete)

            ' Create another save options, with deletions at this time
            Dim saveOptionsWithDelete As New PresentationSaveOptions(PresentationFormats.Pptx)
            ' let the new slide will be 2nd for now, but after deleting it will became the 1st later
            saveOptionsWithDelete.SlideNumber = 2
            '... and we also save the original 2nd slide, which will be next sibling to the newly inserted
            saveOptionsWithDelete.InsertAsNewSlide = True

            'delete the 1st and last slide
            saveOptionsWithDelete.SlideNumbersToDelete = New Int32(1) {
                1,' 1St slide
                22'last slide is 22, not 21, because we inserted the edited 2nd slide as the new slide instance, without rewriting the original 2nd slide
            }
            ' Save it again to distinct file. Output PPTX should have 20 slides now.
            editor.Save(slide2AfterEdit, "Output20Slides-with-delete.pptx", saveOptionsWithDelete)
        End Using
    End Using
End Using

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