CODEWITHSUNDEEP
c++ncurses
var-username
var-username

Reputation: 33

Scrolling but wrapped pad in NCurses

I'm trying to make a text reader/pseudo-command-line a la man, but I'm having difficulty making the text scroll the way I'd like it to. At first I was having trouble getting new text to appear while scrolling, but eventually I found that pads would fix that for me, and I'm currently integrating them.

My question is, how can I get text to wrap within the pad? My program currently automatically refreshes when it is resized, so defining the pad to have as many columns as the terminal wouldn't fix everything. Can I get the pad to automatically resize itself as needed when my terminal receives a KEY_RESIZE? Not just the displayed size, but the size of the pad as well, such that text is pushed down a row due to the end of the pad. Additionally, will resizing it still keep the text, moving it down rows if necessary, or will I need to refresh the content of the pad?

Unfortunately, I'm having trouble finding resources with these details, and the documentation in ncurses doesn't elaborate on the behavior of resizing a pad.

Thanks a lot!

Edit after answered: ncurses doesn't do this, so I'm going to try instead making some arrays of strings, one to store the text from the file (broken at \n), and another for the line wrapping (refreshed on KEY_RESIZE, with each string having a max length of the terminal rows), parts of which are printed to the body window based on scrolling position and such. I'm making this edit so anyone else seeing this problem in the future can see what my solution is. I haven't done this yet, so I'll edit this again if it fails. Thanks again to Stack Overflow for helping with this!

Upvotes: 3

Views: 789

Answers (1)

Thomas Dickey
Thomas Dickey

Reputation: 54668

ncurses will not do what you intend in this case:

  • A pad is like a window, true, and addch will wrap -- but the viewport which you are using to display data in the pad is not a window, and wrapping at the right side of the pad is not necessarily related to that viewport.
  • Once the text has wrapped, ncurses will not remember what that was, and re-wrap text if you resize the window (or pad).
  • A pad is mainly useful when you want to display just part of a window, e.g., if the screen is not large enough for the text you want to display.

If you want to resize and re-wrap, your program should allow for rewriting all of the text in the window (to lay it out as you intend) and not rely on ncurses to decide how to re-wrap text.

Upvotes: 3

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