C++ Pixels In Console Window

Question

In C++ using Code::Blocks v10.05, how do I draw a single pixel on the console screen? Is this easy at all, or would it be easier to just draw a rectangle? How do I color it?

Answer 1

I have drawn the straight line using windows.h in code::blocks. I can't explain it in details, but I can provide you a code and procedure to compile it in code::blocks.

1. go to setting menu and select compiler and debugger.
2. Click on linker tab and add a link library libgdi32.a which is at C:\Program Files\CodeBlocks\MinGW\lib directory.

Now compile this program

#include 

#include 

#define ROUND(a) ((int) (a + 0.5))

/* set window handle */

static HWND sHwnd;

static COLORREF redColor=RGB(255,0,0);

static COLORREF blueColor=RGB(0,0,255);

static COLORREF greenColor=RGB(0,255,0);


void SetWindowHandle(HWND hwnd){

sHwnd=hwnd;

}

/* SetPixel */

void setPixel(int x,int y,COLORREF& color=redColor){

if(sHwnd==NULL){

    MessageBox(NULL,"sHwnd was not initialized !","Error",MB_OK|MB_ICONERROR);

    exit(0);

}

HDC hdc=GetDC(sHwnd);

SetPixel(hdc,x,y,color);

ReleaseDC(sHwnd,hdc);

return;

// NEVERREACH //

}


void drawLineDDA(int xa, int ya, int xb, int yb){

   int dx = xb - xa, dy = yb - ya, steps, k;

   float xIncrement, yIncrement, x = xa, y = ya;

   if(abs(dx) > abs(dy)) steps = abs(dx);

   else steps = abs(dy);

   xIncrement = dx / (float) steps;

   yIncrement = dy / (float) steps;

   setPixel(ROUND(x), ROUND(y));

   for(int k = 0; k < steps; k++){

    x += xIncrement;

    y += yIncrement;

    setPixel(x, y);

 }

}

/* Window Procedure WndProc */

LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam){

 switch(message){

    case WM_PAINT:

        SetWindowHandle(hwnd);

        drawLineDDA(10, 20, 250, 300);

        break;

    case WM_CLOSE: // FAIL THROUGH to call DefWindowProc

        break;

    case WM_DESTROY:

        PostQuitMessage(0);

        return 0;

    default:

    break; // FAIL to call DefWindowProc //

  }

 return DefWindowProc(hwnd,message,wParam,lParam);

}

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int      iCmdShow){

static TCHAR szAppName[] = TEXT("Straight Line");

WNDCLASS wndclass;

wndclass.style         = CS_HREDRAW|CS_VREDRAW ;

wndclass.lpfnWndProc   = WndProc ;

wndclass.cbClsExtra    = 0 ;

wndclass.cbWndExtra    = 0 ;

wndclass.hInstance     = hInstance ;

wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;

wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;

wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;

wndclass.lpszMenuName  = NULL ;

wndclass.lpszClassName = szAppName ;

// Register the window //

if(!RegisterClass(&wndclass)){

    MessageBox(NULL,"Registering the class failled","Error",MB_OK|MB_ICONERROR);

    exit(0);

}

// CreateWindow //

HWND hwnd=CreateWindow(szAppName,"DDA - Programming Techniques",

            WS_OVERLAPPEDWINDOW,

             CW_USEDEFAULT,

             CW_USEDEFAULT,

             CW_USEDEFAULT,

             CW_USEDEFAULT,

             NULL,

             NULL,

             hInstance,

             NULL);

if(!hwnd){

    MessageBox(NULL,"Window Creation Failed!","Error",MB_OK);

    exit(0);

  }

  // ShowWindow and UpdateWindow //

  ShowWindow(hwnd,iCmdShow);

 UpdateWindow(hwnd);

 // Message Loop //

 MSG msg;

 while(GetMessage(&msg,NULL,0,0)){

    TranslateMessage(&msg);

    DispatchMessage(&msg);

 }

  /* return no error to the operating system */

  return 0;

}

In this program I have used DDA line drawing algorithm. Pixel drawing tasks is done by setPixel(ROUND(x), ROUND(y)) function. This is windows programing which you can learn details here