Copy and Reorder Slides

CopySlide takes a slide from any open presentation and appends it to this one. MoveSlide then puts it where it belongs, because a copy always lands last. Between them they cover assembling a deck from parts: a standard title slide from one file, content from another, a fixed closing slide from a third.

Copying between presentations

pptFrom, err := presentation.Open("source.pptx")
if err != nil {
    return err
}
defer pptFrom.Close()

pptTo, err := presentation.Open("extract.pptx")
if err != nil {
    return err
}
defer pptTo.Close()

if _, err := pptTo.CopySlide(pptFrom.Slides()[0]); err != nil {
    return err
}
if err := pptTo.MoveSlide(len(pptTo.Slides())-1, 1); err != nil {
    return err
}
pptTo.SaveToFile("output.pptx")

Both files stay open until the copy is done, since CopySlide reads from the source presentation rather than from a detached slide value. The slide XML is marshalled and unmarshalled, so the copy is independent of the original and editing one does not affect the other.

If the source slide’s layout is not already in the destination, CopySlide brings it across along with the layout’s images, registers it on the destination master, and points the new slide at it. That is why a copied slide keeps its design instead of falling back to whatever the destination’s first layout looks like.

Passing a slide from the same presentation duplicates it. The layout lookup finds the layout already present, so only the slide part is copied.

Moving slides

MoveSlide indexes the slide list, zero-based, and returns an error when either argument is outside it. Moving a slide to its own position is a no-op rather than an error. The example moves the freshly copied slide to index 1, making it the second slide, not the first.

Positions are evaluated against the list as it is when you call, so moving several slides means recomputing indices after each call rather than planning them all up front.

Limitations

Only the layout’s relationships are carried onto the copied slide. The source slide’s own relationships are not, so a picture, chart or hyperlink placed directly on the slide being copied loses the part it points at. Slides whose content comes entirely from the layout and from text copy cleanly. This is read from CopySlide in the library source rather than observed, so verify against your own decks before relying on it.

Speaker notes attached to the source slide are not copied either.

Slides() returns fresh Slide values each call, and CopySlide wants one of those values, not an index. Calling len(pptTo.Slides())-1 immediately after a copy is the reliable way to name the slide that was just added.

Run the example

The example copies the first slide of source.pptx into extract.pptx, moves it into second position and writes output.pptx.

git clone https://github.com/unidoc/unioffice-examples.git
cd unioffice-examples/presentation/copy-reorder-slide
go run main.go

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