How to create custom layouts in Impress?

I want to create several Impress layouts, different from those already provided. For example, with title field in one short column and content in second wide column, or a slide with only text content (no outline text) but no title.

I am not talking about master templates, which are in charge for decorative elements. I am talking about the layouts like those that are in a panel in sidebar, below Properties panel.

Might be a solution to do it with a macro, but I do not know so much about the API of Impress.

No, I’m not aware of any solution.

Finally, you should select and customize a layout for your purposes and then save it as a template.

Do you mean saving it as a master? or a template itself?

First as master, then as document template.

See also:

Create Master Slide and Presentation