/* Filename:  Simple.cpp

   Programmers:  Brian LaSitis, Br. David Carlson

   Date:  March 4, 2003

   This Win32 program illustrates simple graphics by drawing one line diagram in a window.
   There is no interaction with the user.

   Although much of the Windows code in the program is not understandable to beginning
   students, the WM_PAINT section in the WndProc function is fairly easy to follow.
   Students who have a basic understanding of calling class functions can read this
   section of code and modify it to draw something of their choosing.

   Tested with:
      Microsoft Visual C++ 6.0
      Microsoft Visual C++ .NET
  
   To compile this program in Visual C++ 6.0, create a new project of type "Win32 Application"
   (not Win32 Console application) and then make sure that "empty project" is selected.
   Do not select Console application.  You can then create a new C++ source file for this project
   and paste in this code.

   To compile this program in Visual C++ .NET, create a Visual C++ project of type "Win32 project"
   (not Console application) and under Application settings be sure that Windows application and
   Empty project are checked.  You can then create a new C++ file for this project and
   paste in this code.
*/

#include <windows.h>

// Function prototype:

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);


// For a Win32 app, there is a WinMain function, not a main function.  Ignore the gory Windows details.
INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, INT iCmdShow)
   {
   TCHAR szAppName[] = "WinApp";
   TCHAR szWndName[] = "Simple Drawing";

   HWND hWnd;
   MSG msg;
   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;

   if (! RegisterClass(&wndclass))
      {
      MessageBox(NULL, "Could not create window.", "Error", 0);
      return 0;
      }

   hWnd = CreateWindow(szAppName, szWndName, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT,   CW_USEDEFAULT, 580, 400, NULL, NULL, hInstance, NULL);

   ShowWindow(hWnd, iCmdShow);
   UpdateWindow(hWnd);

   while (GetMessage(&msg, NULL, 0, 0))
      {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
      }

   return (int) msg.wParam;
   }


// This function processes the various messages for the window.
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
   {
   switch (message)
      {
      case WM_CREATE:
         return 0;

      case WM_PAINT:
         HDC hDC;
         PAINTSTRUCT ps;
         HPEN hOldPen, hNewPen;

         hDC = BeginPaint(hWnd, &ps);
         hNewPen = CreatePen(PS_SOLID, 1, RGB(0, 180, 180));   // aqua color (mixes green and blue)
         hOldPen = (HPEN) SelectObject(hDC, hNewPen);

         //*** Students: try changing the section between this comment line and the one marked below. ***

         // Print a message string:
         TextOut(hDC, 50, 50, "Line drawing", 12);

          // Draw a rectangle:
         MoveToEx(hDC, 100, 200, NULL);
         LineTo(hDC, 300, 200);
         LineTo(hDC, 300, 300);
         LineTo(hDC, 100, 300);
         LineTo(hDC, 100, 200);

         // And top it with a triangle:
         LineTo(hDC, 200, 100);
         LineTo(hDC, 300, 200);

         //*** Students: this is the end of the section that you might try to change. *** 

         EndPaint(hWnd, &ps);
         return 0;

      case WM_DESTROY:
         PostQuitMessage(0);
         return 0;
      }

   return DefWindowProc(hWnd, message, wParam, lParam);
   }