Add layout to existing powerpoint file

[mystvearn]

I'm trying to figure out how to add new layout to existing slide masters. I've read through the document as well as tried to use append (array) but couldn't figure out how to make it work. Am I missing something or the method is currently not available?

[scanny]

This is a good question. The short answer is it's not supported yet; we've actually had very few folks want to manipulate a "template" using python-pptx, perhaps because it's so easy to do by hand and generally only needs to be done once for a given set of presentations.

Note that you can open a template (starting-point) presentation of your choice when opening a presentation using prs = Presentation('arbitrary-deck.pptx') and that all the masters and layouts from that deck will then be available for your use in the presentation you make from that starting deck (which will often have zero slides, just for that reason).

If that approach doesn't suit, then if you can describe your use case that would help identifying the required features. Slide layouts have a particular set of behaviors, particularly involving adding placeholders, which is not allowed on slides. So while adding a new layout would be a start, there would be a lot more to it.

[mystvearn]

My use case is that I want to automate the layout design a bit. For example swapping positions of shapes in the template from left to right. So far I have achieved this part - editing the layout. The only issue is that the new layout will overwrite the existing layout. Even if I save the layout to a new slide then try to add it back using "prs.slide.add_slide(new_layout)". The way I work around this is adding some manual work by creating duplicates of the layout that I want to create varies and then modify these layouts.

Here is my code for modifying the layout:

def create_new_layout(old_layout):
    new_layout = old_layout
    new_layout.name = "CONTACT"
    swidth = prs.slide_width

    index = 0
    for shape in new_layout.shapes:
        new_layout.shapes[index].left = swidth-(shape.width+shape.left)
        index += 1

    return new_layout
from pptx import Presentation
from pprint import pprint

prs = Presentation("template.pptx")
properties = prs.core_properties
slides = prs.slides
layouts = prs.slide_layouts

contact_layout = layouts[4]
contact_layout = create_new_layout(contact_layout)
prs.save("template.pptx")

It would be great if there's a method, for example, layouts.append(new_layout) to append new layout into slide master.