Dragging from the rulers does not always create snap guides. If it doesn't, click on the slide background, "Snap guides", "Insert snap guide". In my case, after the first snap guide was manually inserted, it was possible to drag new one from the rulers.
How to edit a master slide
- Show master slides side pane
- Right click on master slide
- Edit Master...
- An icon appears in the toolbar: "Close Master View"
- Apply to all slides might not apply to the first slide created as the document was opened
Change styles in master slide
Do not change properties of text by selecting placeholder text in the Master View. Instead, open the Styles and formatting sidebar, and edit the styles in there.
This means the style changes are applied to pages in all layouts, not just the "Title, Content" layout that is the only one editable in the "Master View".
How to duplicate a master slide
There seems to be no feature implemented for this, but you can do it, if you insist:
- Save a copy of the document
- Rename the master slide
- Drag a slide, that uses the renamed master slide, from the copy of the document to the original one
It's needed enough that someone made a wikihow: https://www.wikihow.com/Copy-a-LibreOffice-Impress-Master-Slide.
How to change the master slide for a layout that is not "Title, Content"
I could not find a way to do it, but read on for a workaround.
I found an ask.libreoffice.org question that went unanswered.
I asked on
#libreoffice on IRC and got no answer:
Hello. I'm doing the layout for a presentation in impress, and I can edit all sorts of aspects of the master slide. It seems that I can only edit the "Title, Content" layout of the master slide, though. I'd like to edit, for example, the "Title only" layout so that the title appears in a different place than the top of the page. Is it possible to edit specific layouts in a master page?
In the master slide editor it seems impossible to select a layout, for example.
Alternatively I tried creating multiple master slides, but then if I want to create a master slide for a title page, there's no way to remove the outline box, or the title box.
My work around has been to create multiple master slides, one for each layout. For a title layout, I moved the outline box into a corner, and one has to remove it manually after create a new slide.
There seems to be no way of changing the position of elements not found in the "Title, Content" layout, like "Subtitle". On the other hand, given that one's working with an entirely different master slide, one can abuse the outline box as a subtitle.
Note that if you later decide to change a style element for all the slides, you'll need to go propagate the change to the "Styles and Formatting" menu of all master slides you're using.