The projection you are talking about is a projection that is printed on film and then projected, or is it a projection that is directly connected to the computer and played back? If it is what we usually call computer projection, we usually use ppt, which is produced and played using Power Point in Office software. Sound animations can be added or not added to the ppt. When playing the demonstration, it can be full screen and easily switched. . Of course, the pdf file can also be opened on a computer and viewed with a projector. Such an operation is no different from playing a word document or other documents. It is just viewed on the projector as a large computer screen. Generally speaking, it should be full screen. It's possible, but at this time it's more troublesome to control the position of the text and adjust it to a suitable size for presentation to the audience. After all, Pdf is generally not used for presentation projection, but a general electronic document publishing format.