A Line

Is there a way to get a program to draw a line between two points?

Any simple tutorials on the web would be very useful.

here's one - wether or not this is what you are looking for

http://www.cprogramming.com/tutorial/tut3.html

Anyone else?

Well you could start with which OS / Compiler / graphics library you're using.

Windows XP / Dev-C++ / none

So far I have this:

http://www.adrianxw.dk/SoftwareSite/...Consoles3.html

Here's a little example using LineTo (must use windows 2000 or later):

Code:

---

#define _WIN32_WINNT 0x0500 //specifies the windows version is windows 2000 (to use GetConsoleWindow)
#include <windows.h>
#include <iostream>


int main()
{
  HWND hwnd = GetConsoleWindow();
  if (!hwnd)
    std::cout<<"Error getting console window handle!";
 
  HPEN hPen = CreatePen(PS_SOLID,5,RGB(255,255,255)); //create a solid white pen of width 5
 
  HDC hdc = GetDC(hwnd); //get the device context
 
  SelectObject(hdc,hPen); //select white pen
  MoveToEx(hdc,0,0,NULL); //move to 0,0
  LineTo(hdc,100,100); //draw from 0,0 to 100,100
 
  ReleaseDC(hwnd,hdc); //release the device context
 
  DeleteObject(hPen); //delete the pen
}

---

When tryign to compile that i get:

implicit declaration of function `int GetConsoleWindow(...)'

initialization to `HWND__ *' from `int' lacks a cast

What do those errors mean?

> implicit declaration of function `int GetConsoleWindow(...)'
Either you spelt it wrong, or you're not including the correct header files.

Well I just copied that code into a new source file.

Go to the menu...


File>new>project>windows application>

Type in a name for your file. Then copy and paste your code in there.

Does it need to be put in with all the stuff about making a window?

No try jawib's code on its own.

Why doesn't it work then?

By not work you mean?

Are you getting any compiler errors?

Yes which I posted earlier...both on the line:

Code:

---

HWND hwnd = GetConsoleWindow();

---

I don't know then.

I will try a different compiler.

Good lord. Just install a simple graphics lib, Like Allegro or SDL and draw some lines.
http://www.libsdl.org/index.php
http://www.talula.demon.co.uk/allegro/

Well, the code posted is exactly what I need but it doesn't work and I don't know why.

I there any other code that I can use?

You might try using GetForegroundWindow() instead of GetConsoleWindow(). I don't know why the code I posted doesn't work for you (it compiles fine with visual studio, so it must be an issue with your compiler's headers)

Any reason why it wouldn't work with Dev-C++

I compile it with foreground window and I think there is a linking error...it compiles but won't run...

Anybody know what I would need to do to get the program working?

I went ahead and tried this with the latest Dev-C++ version and it works fine. You just need to link libgdi32.a and add a pause at the end so that the program doesn't terminate automatically.

How do I link the library?

Go to project options->parameters then under "Linker" click the "Add Library or Object" button, go to the lib directory and find the lib file.

Erm, I am using version 4 of Dev-C++

I honestly don't know what the differences between the versions of Dev-C++ are. Either way, make sure you actually created a project (if you just open a .cpp file you won't be able to change the linker options). There has to be a setting somewhere once you've done that...

I have found where to add the library and I have tried adding it the way it tells me and it still doesnt work.