Right now, I have a console application I'm working on, which is supposed to display and update information to the console at a given interval. The problem I'm having is that with a carriage return, I can only update one line of text at a time. If I use a newline, the old line can no longer be updated using a carriage return.
What can I do here?
You might be able to find a curses library variant that works on your platform.
The correct answer is to use the curses library as mentioned by Mark. But if you're on Unix-like systems and can't be bothered with curses then the quick and dirty solution is to directly print out vt100 escape sequences:
http://ascii-table.com/ansi-escape-sequences-vt-100.php
I often do this especially in scripting languages that doesn't have a curses binding.
This is a really ugly solution, but in a pinch you could always just clear the console entirely and then reprint everything. This strategy looks a bit ugly in some cases; it may make things look blinky.
Related
Title says pretty much everything. Once upon a time when I was under 13, my older bro did in BorlandPascal a thing which amazed me. He defined kind of table [8][8] with values of 1 and 0, meaning respectively foreground and background. Having several of such tables he could somehow redefine default ASCII characters to look like in these tables. I have no idea how it was done, but it worked.
My question is: can I do similar thing in ncurses, and if I can then how to do it?
The short answer is no. What ncurses does is generating ANSI escape codes which are interpreted by the terminal. There are no codes for altering the font. (Althou there have been extensions propesed no commonly used terminal supports them, neither does ncurses.) And there is no generic way of communicating with the terminal through some kind of side channel for changing the font. But there might ways in some specific situations.
If you have direct access to a Linux console for example you could could do all sorts of things, much like in Borland Pascal. But it will likely be more messy and less impressive.
As the selected answer explains, this is not possible for NCurses to render custom glyphs. ncurses only manipulates the terminal screen state via escape codes (Clearing and rewriting lines to achieve interactivity).
However it should be noted that's very possible to use custom glyphs in the terminal via custom fonts.
This is what Powerline does (a popular terminal UI status line for vim, tmux and friends): https://github.com/powerline/fonts
By patching the fonts, you can inject your glyphs into the existing font being used by the terminal, which then you can access and render via ncurses as any other character.
Of course this is not ideal solution, but with some auto patching of the fonts, and careful testing, it makes it possible to build an app that uses custom glyphs—when your really in a pinch for more expressive UI tools than ncurses can offer.
Further reading: https://apw-bash-settings.readthedocs.io/en/latest/fontpatching.html
actually i'm thinking of creating a cool interface for my programming assignment , so i go around searching on how to do it so that such an effect can be create , below is the image .
The Question
1.)What is needed in order to create a program that run pseudographic(semigraphic or whatever they called it) that has menu like BIOS wizard did??I always see some program run in console but it could have graphical-like looking , for example blue environment , and user can use keyboard to choose a list of setting in a menu.
Thanks for spending time reading my question.
It's called Text-based user interface. There're several libraries for doing this. I think this is what you're looking for. :)
Cross platform, Interactive text-based interface with command completion
http://www.gnu.org/s/ncurses/
Ncurses(or maybe pdcurses) is probably what you need.
In the days of 16-bit Windows console windows used to support ANSI escape sequences (via the ansi.sys driver), but they no longer do.
For the apparent line graphics you need to use a platform specific solution anyway, so I recommend just writing an abstraction (functions, class) over the Windows APIs console functions.
The line graphics is done by using characters from the original IBM PC character set, codepage 437. At first you can just hardcode the various patterns. In order to make it seem more like line drawing to the code, or from the code's perspective, so to speak, you'll have to abstract things again. As I remember there is some partial but not complete system in the original codepage 437 character codes. But for Windows console you will need to use the Unicode character codes, which probably do not preserve the original system, so perhaps just define a map where these graphics characters are placed more systematically.
Possibly that already exists.
If you don't care about portability, the Windows API for this can be found here. It will supply all the functions you need, without the need to pack additional libraries with your application.
You can also look in to graphics.h, a non-standard Borland extension that a lot of older graphical games used to use. It goes far beyond the normal limits of the console, but is only supported by 16 bit systems, of which Microsoft has all but removed support for from Windows. You'd also need an ancient Borland compiler, or an emulation, though you probably want the original look and feel.
I am doing an exercise from The C++ Programming language (page 325, exercise 12.7, question 2).
It says:
Implement a simple graphics system using whatever graphics facilities
are available on your system (if you dont have a good graphics system
or have no experience with one, you might consider a simple "Huge bit
ASCII implementation" where a point is a character position and you
write by placing a suitable container, such as * in a position)
Now, what I gather from that, is that if I dont want to use GDI+ or Direct X then I can do this in a console app using chars like _,*, or -.
Am I thinking about this the right way?
If I am, am I right in thinking that I need to be able to draw a character anywhere on the console?
If so, how do I draw a char anywhere on the console?
Or I could be wrong and you can tell he what I might want to try (not GDI+ / DirectX if possible)
In order to draw a character anywhere to the console you really need to use an operating system specific library for console access, or a cross-platform console library.
If you were doing this for Windows you would use the Windows Console API (MSDN), a function that could draw a character to a specific location is FillConsoleOutputCharacter (MSDN).
It used to be that ANSI escape sequences could be used, but having read your question and investigated here, it seems these no longer exist.
The best option appears to be to use the windows console APIs, documented here.
There looks to be a pretty good example of how you might proceed here.
Good luck with this, it sounds interesting!
Fond memories of doing this in computer class, back when we had chaarcter sets with ▄ ▀ █. Double-resolution graphics ;). If you wanted one in column 8, you'd print 7 spaces in front of it. And if you wanted it at line 3, you'd print two \n in front. But yes, you'd have to consider up front what you were going to draw. To redraw one character, you'd have to redraw everything.
I want to partition the output screen into two parts (just like frames do it in HTML). So that one part may remain fixed and display some content which is updated based on input received from the other part.
I do not wish to venture into GUI stuff therefore OpenGL, SDL etc are ruled out (I wish to do it in command line mode). I have Borland C++ with graphics.h support, but it is just too old to carry on.
What alternatives do I have at my disposal (If not C++, a solution in C will also be Ok.)
You may want to take a look at curses-like libraries like PDCurses.
Other than that, you may use ANSI terminal escape sequences to control the cursor on a text window, this may be quicker if what you are doing is simple, otherwise use PDCurses and it will handle the escape sequences for you.
Check out Curses / NCurses.
I am trying to write a C++ program where the screen updates every 1 second. However, I want the screen to be similar to htop, where it updates and does not have to scroll with each update. That way, I don't have a step-by-step iteration in my terminal.
Does anyone know what this style is called or how to program it?
Thanks!
The usual way is with something like ncurses. If you're on Windows, it has console functions built in so you can do the same without any extra libraries (though they do take a while to understand). If you only want one line of output, you can use a '\r' to return to the beginning of the current line and/or \b to backspace over previous characters (handy if yoy only want to overwrite a few little bits and pieces).
You'll need a library like curses (on *nix) or pdcurses for Windows (conio functions would probably still work on windows).