I've been looking everywhere but cannot find an answer, is it possible to draw a pixel in C++ without a library, to the console, where I decide where to plot it(x,y).If not, how does a library manage to do this, I read it had something to do with the library gaining access to the drivers on the computer, but even then its still part of the C++ program.By the way I have never had formal programming education so this may seem silly.
This is possible, but highly dependendt on your operation system. You will have to use the OS API, because the C++ standard in itself doesn't have any idea of that kinda stuff.
For example, Windows has the SetPixel function that can be used on the console window. You can get the console window by using GetConsoleWindow and its context using GetDC.
That said, it's one of the less orthodox things to do, not portable and hard to predict - redraws of the console window will erase your content. Reconsider your options, and think about whether using a library might not be the better idea.
Related
My question is that, how Can I draw one single pixel on the screen using C++ native libraries and functions? I mean not to use external functions or libraries. How is it possible?
Something Like this:
int rgb = {255,150,113};
nativeLibrary.drawPixel(0,1, rgb);
A fancy example just it is.
You can't. C++ does not (yet) have any native graphics or GUI libraries.
C++ may eventually add graphics into the standard (they were considering it), but for right now, the C++ standard does not include graphics.
You can take advantage of other standards in order to write a pixel to the screen, though. If you're on Linux, there is already an answer up.
If you're using VGA, you can actually write directly to the VGA buffer (WARNING: WAY OUTDATED Like "meant for DOS" outdated). You would probably use C++'s inline assembly to set the render mode instead of whatever that page uses, then use a regular unsigned char* instead of a "far" pointer to access it. Although you probably aren't using VGA and probably don't want to use assembly (especially inline assembly).
So what do you do outside of that? Nothing, really. You need to use an external library specifically to render, so probably OpenGL or DirectX or some library making use of either.
Like the previous answer, there no native library to deal with images. However, if you are working in Windows API and particularly MFC, you may use CBitmap class.
I read something from here that said using GLUT is considered unprofessional. Swiftless has a fair amount of tutorials and I would consider him among NeHe as "go to OpenGL examples and tutorials". I have used GLUT in several languages in a few projects, though mostly for school projects. I find it very easy to make cross platform OpenGL apps with it.
Is using GLUT unprofessional? If so why?
GLUT is no longer under active development, that's one reason not to use it.
Another is that other wrappers (GLFW, SDL) are not only under active development, but generally more powerful.
Also the callback-oriented API of GLUT is usually not considered very usable. I mean, it works and it is certainly possible to use it, but both GLFW and SDL want you to write the main loop of your program yourself (SDL also has platform-independent yet explicit message handling) which, at least in my opinion, results in MUCH more clear and flexible code.
My conclusion: using some platform independent wrapper for OpenGL is certainly better than, say, WinAPI, but GLUT is probably not the best choice among the wrappers which are available.
No, it is not unprofessional. Use whatever is easiest and fits your requirements. I find freeglut better then glut (different license, and provides better flexibility), but it should be fairly easy to switch from glut to qt or sdl.
I can only argue for it being unprofessional on one point only: it may not be so portable to other platforms (such as Bada OS).
I have been looking all over the web for the simplest solution for this, and currently I have come across nothing that seems simple enough for my needs.
I am looking for a way to manipulate a matrix of pixels manually in C++, platform independent.
Does anyone know of a library that is simple to use that will help me obtain this?
Use SDL
Use OpenCV
By virtue of it being platform independent, you're probably not going to find a library that does only this. There are libraries like SDL and directFB that will let you do this, but not without extra baggage. X11 may even be a better choice. It supports things you don't need, but it also allows you to easily render pixels directly to the screen (or window, as the case may be).
I do have to say I'm fairly inexperienced when it comes to C++, don't be too harsh on me.
Recently stumbled unto the wonders of the win32 API and have chosen to practice using it (I'd rather not use MFC/wxWidgets/etc at this point, just for educational purposes).
Well, my real question is:
How do you properly code your win32 GUI stuff into classes. I mean, sure, you can make a class that saves individual window handles, allows for easier modification of window properties, has a more simplified version of CreateWindow(). But as I understand it you will need a messagepump and several callback functions for your created windows. How does that work when combining them with classes?
Could anyone point me in the right direction here? I don't mind reading (a lot of) example code as long as it is commented.
PS: I'm also having trouble finding good (read: easy) documentation on using 'resource files' for my window decorations. Bonuspoints for that! :)
I program in C++ for a living. I like C++.
That said, your life will be so much easier if you do your windows GUI in something .Net, e.g., C#. Win32 is very low-level and you will be building tons of stuff that you will get for free with the .Net libraries. Win32 is not a wonder, anymore. :-)
If you want to learn C++, pick something other than a GUI to do with it.
I personally would use MFC instead of reinventing the wheel here. However, if you insist you need to have an application object that is instantiated when the program is run and contains the message loop and a mechanism for forwarding messages to the correct window objects.
That's the way MFC does it, at least. I'm not sure if the MFC source code is available for download, but if you have access to Visual C++ install disks (any version) you should be able to install the source code on your computer to review.
The biggest problem I faced back when I used the Win32 API (have since moved on to Linux and cross-platform solutions) were the callbacks. Especially the winproc one, AKA the message pump. I found this, which should be a good hint. I did what that page suggests when I rolled my own wrapper.
Look at MFC or ATL/WFC. If you want to re-invent the wheel, the best reference source for how to do so is the wheel itself, especially since the source code is readily available.
I would suggest reading Windows++ by Paul Dilascia. It takes you through the whole process of building a class library in C++ on top of the Windows API. It's written for 16-bit Windows, but all of the concepts presented in the book still apply. Plus, you can get it really cheap since it's "out of date".
And make sure you learn about message crackers (#include <windowsx.h>), they will keep you from pulling out too much hair. ;-)
The best way to learn this is to go and readCharles Petzold's original book. He does a good job of showing how to set up the base message loop and how to build statements for routing the various events to handlers. The real problem here is that by reinventing everything you are going to be spending hours and hours writing and debugging windows event hanlding code instead of writing your own application.
Unless you have a compelling reason for doing this yourself, you woudl be far better served using someone else's construct like MFC.
The only reason I see for coding all this yourself is if you want a basic understanding of how it works before you switch over to MFC or something similar. At least this way you would see how it works under the covers before you can forget it forever.
Many years ago, I developed a set of classes to encapsulate the API (various reasons why we couldn't use MFC). I learned a lot from the MFC source code.
The big key is that every window has a UserInfo data member - you can use it for whatever you want. What you'll want to use it for is the class's this pointer.
Now, the other tricky thing is that the message handler callback function cannot be a normal class member function, as Windows uses C calls and not C++. So your callbacks must be statics. However, since you've saved the class's this pointer, its just a matter of getting the class's userinfo, casting it to your class's this pointer and then calling whatever (non-static) class functions you need.
If you plan it correctly, inheritance will work well, including all of the inheritance that the windows themselves exhibit (ie, an Edit is a Control is a Window).
The only reason I would recommend not reinventing the wheel is you are neither an expert at C++ nor the Win32 API. Trying to learn two unrelated subjects at once will not be productive. If you want to become better at C++, write a library for a subject you know a lot about. If you want to learn the Win32 API, program it raw to understand how it works before creating (or using) a wrapper for it.
There is a pretty good C++ Windows API tutorial on the Reliable Software site.
My main experience is with C && C++, so I'd prefer to remain with them. I don't want to use anything like QT, GTK, or wxWidgets or any tool kits. I'd like to learn native programming and this sort of defeats the purpose. With that in mind I'd also like to avoid Java.
I understand gnome and xfce and KDE and such are all Desktop Environments for Linux, and the base installed typically is X (Xorg). When coding for Linux, do you code for X, or for the desktop environment? Is there a standard Linux header for this (like win32 has windows.h) for Linux? or is it different coding methods for every desktop environment?
any help is greatly appreciated.
X is a hideous layer to program for and, despite your intent to avoid Java, QT or any of the excellent UI abstraction layers, you'll be doing yourself a disservice by coding to that level. I've done it (a long time ago when Motif was in its infancy on the platform we were using) and I would not do it again if there was an easier way.
Your use of the phrase "native programming" confuses me a little. If you want to learn native programming, it's to the APIs that you choose to call. Using similar reasoning, you shouldn't be coding in C either, instead opting for assembler (or direct machine code) since C provides an abstraction to the hardware.
If you want to learn X programming, that's fine. You'll end up with a lot more control over your interface but almost everyone else will be out-performing you in terms of delivery of software. Myself, I'd prefer to code to a higher-level API that I can use on many platforms - it gives me both faster delivery times and more market potential.
You don't build a house out of atoms, you build it out of bricks. My suggestion is to use the tools, that's what they're there for.
I don't want to use anything like QT, GTK, or wxWidgets or any tool kits. I'd like to learn native programming and this sort of defeats the purpose.
No you don't. Back in an early version of X11, like R1 or R2, I coded a complete "Hello, world" program in Xlib alone.
Roughly 700 lines of C.
You don't want to go there.
I guess you could write C code directly against Xlib, but you'd end up recreating all the functionality that GTK+ or QT provide that X doesn't alone.
Unix (and by extension, Linux) doesn't actually define anything to do with GUIs. X, which is commonly used, doesn't define anything to do with widgets or styles or anything of that nature - it's concerned mostly with drawing primitives and event handling. Essentially, if you wanted to write in pure X, you'd be defining the shape and behaviour of every element on screen. If you were crazy enough to abandon X, you'd be working at the graphics framebuffer level...
You're better off using some toolkit - if you're looking for light-weight, why not try FLTK?
GTK, QT and wx are toolkits that build on X to provide a friendlier API.
If you don't use an existing toolkit you'll need to write things at a very low level - directly handling mouse and keyboard events. If you want a button or a textbox you'll have to write it yourself using the low level xlib primitives.
Before trying this you're probably better off picking the toolkit of your preferred desktop environment and starting with that.
There is simply no such thing as "native" in this case. Windows and OS X just have an official option, while X does not.
The "native" interface for Linux & most other Unix-like OSs is Xlib, the lowest-level C API for X11.
GTK, Qt & others are all (so far as I know) implemented in terms of Xlib at their core. As others have said, Xlib gives you maximal control but you'll have to work for it (and others may run circles around you in terms of delivering a product).
As a point of reference, I personally implemented a fairly feature-rich & modern (i.e. flowable) cross-platform (Win32 + X11) GUI library in C++. Total count is about 29 KLOC of C++, of which about 2500 lines each was required for the X11 & Win32 shimming. The rest is for platform-neutral Widget implementations. Unless you're prepared to make a commitment like that, I strongly recommend going with one of the higher level libraries (Qt would probably be my choice, though I can't stand the preprocessor approach).
BTW, a big plus for Xlib is its raw portability--any Unix box with a screen will have it, and it can be made to work on Windows & OS X as well.
I feel it necessary to counterpoint the unanimity of the other answers here. X11 is indeed low level. But to "truly" understand what's going on, you should have some familiarity with how X11 works. Since all the toolkits work on top of X, you're using it whether you like it or not. There is nice tutorial online somewhere that I'm too lazy to search for. It guides you through building a simple Hello World. To do it, you'll have to learn how to create a window, request events, map the window, and process events in a loop. You could even go so far as to order some used books on Amazon. The O'Reilly vols 1 and 2 (for now get the cheapest editions, but nothing earlier than X11R4) are essential for reference and to get the full story of how the pieces work together. For learning, however, the best book is X Window Applications Programming by Eric Johnson and Kevin Reichard.
At some point along this journey, as everyone else says, you will find you've had enough. Two pages of code just to select a visual, and then you still have to populate a colormap before you can paint your custom bitmap. And then two days of rewriting and debugging to realize that it all does work; you just forgot to XFlush()!
The struggle is important, because you'll appreciate the toolkits more once you find the one you like.
I would suggest lesstif/motif as well. It also builds on top of X and the learning curve is, in my opinion, isn't as steep as GTK or Qt. The UI's you build with it aren't going to be as sophisticated as ones you could build with GTK or Qt though. More information can be found here.
As others have mentioned you probably don't want to X it's a pain.
Why not choose one among, say, Qt, wxWidgets and GTK and learn its internals, rather than its API? I do not mean just for the sake of it, but with the aim of contributing to the parts you find most appealing. In this way you'd fulfill your goal and get to do something useful, for you and also for others. I think this would be more rewarding than assigning yourself the rather artificial task of building an application with what amount to the wrong tools.
oh yeah, there is such "native" things:
FBUI, svgalib, directfb, exa(kdrive), SDL, Allegro..+Wayland, although not mainstream.
http://home.comcast.net/~fbui/
http://www.svgalib.org/
http://directfb.org/
http://xorg.freedesktop.org/wiki/ExaStatus
+
http://wayland.freedesktop.org/