I want to set the zoom level in TextEdit to a precise value so that the on-screen display has the same size as the printout. The "Zoom in" and "Zoom out" controls are too coarse for this.
The following workaround does at least provide a fixed user-settable zoom (TextEdit 1.13, OS X 10.13.6 [High Sierra]).
- Create and save a blank TextEdit doc (maybe make it Stationery via Finder Info)
- Open the doc in TextEdit (don't use "Open Recent") and select the Option button to "ignore rich text commands". (Or, open it in some text editor which doesn't do RTF.)
- Add the command
\viewscaleNNNin the header material; or, preferably, the command string
This does the following: set the left margin to 1 inch (1440 units, whatever they are), the right margin similarly, the window width and height to big enough that the doc will open showing a full page (otherwise you get the middle of the page but not the edges), the "viewkind" command (use 1 as shown for Page Layout view, called "Wrap to Page" in TextEdit), and finally the viewscaleNNN command, with "NNN" here being "140" setting the zoom to 140%, which is what is needed on my particular setup; experiment to find the percentage you like. These and many more RTF commands may be found here.
- Finally, save the doc and use it as stationery.