#include <stdio.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
        char temp[80];
        PAINTSTRUCT ps;
        HDC hdc;
        static int count;
        switch(uMsg)
        {
        case WM_CREATE:
                count = 0;
                break;
        case WM_PAINT:
                hdc = BeginPaint(hWnd, &ps);
                sprintf(temp, "Count = %d", count);
                TextOut(hdc, 50, 50, temp, strlen(temp));
                EndPaint(hWnd, &ps);
                break;
        case WM_LBUTTONDOWN:
                count++;
                InvalidateRect(hWnd,NULL,TRUE);
                break;
        case WM_RBUTTONDOWN:
                count--;
                InvalidateRect(hWnd,NULL,TRUE);
                break;
        case WM_DESTROY:
                PostQuitMessage(0);
                break;
        }
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
}




#include <stdio.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
        char temp[80];
        PAINTSTRUCT ps;
        HDC hdc;
        static int count;
        static int m_bFlag;
        switch(uMsg)
        {
        case WM_CREATE:
                count = 0;
                m_bFlag= 1;
                break;
        case WM_PAINT:
                hdc = BeginPaint(hWnd, &ps);
                if(m_bFlag)
                    strcpy(temp,"Toggle");
                else
                    strcpy(temp,"");

                TextOut(hdc, 50, 50, temp, strlen(temp));
                EndPaint(hWnd, &ps);
                break;
        case WM_LBUTTONDOWN:
                m_bFlag = !m_bFlag;
                // 화면을 즉각즉각 재출력을 해주는 함수(자주쓰이는 함수)
                InvalidateRect(hWnd,NULL,TRUE);
                break;
        case WM_DESTROY:
                PostQuitMessage(0);
                break;
        }
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
/*

  Data를 Toggle하는 방법
  1. 1,0 toggle
        int flag = 1;
        flag = 1 - flag (flag = !flag)
  2. 1,-1 toggle
        int flag = 1;
        flag = flag*-1 (flag *= -1)
  3. 0,1,2 순차적으로 반복하는 round toggle
        int flag = 0;
        flag++;
        flag %= 3;


  변수이름에 m_을 표시하는 이유
    Member변수라는 뜻이다. 이는 class로 프로그램을 작성할때 주로 사용하는
    Naming Rule이며, MFC프로그래밍 스타일의 습관을 그대로 따랐다.
  */
  
  
  

#include <stdio.h>
POINT CenterPoint(RECT& r);
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
        PAINTSTRUCT ps;
        HDC hdc;

        static char     m_Str[80];
        static POINT    m_Point;
        static RECT     m_Bound;

        switch(uMsg)
        {
        case WM_CREATE:
                strcpy(m_Str, "Catch me~~");
                GetClientRect(hWnd, &m_Bound);
                m_Point = CenterPoint(m_Bound);
                // string 길이의 반만큼 옆으로 가도록 함
                m_Point.x -= (strlen(m_Str)*8)/2;
                break;
        case WM_PAINT:
                hdc = BeginPaint(hWnd, &ps);
                TextOut(hdc, m_Point.x, m_Point.y, m_Str, strlen(m_Str));
                EndPaint(hWnd, &ps);
                break;
        case WM_LBUTTONDOWN:
                m_Point.x -= 20;
                InvalidateRect(hWnd,NULL,TRUE);
                break;
        case WM_RBUTTONDOWN:
                m_Point.x += 20;
                InvalidateRect(hWnd,NULL,TRUE);
                break;
        case WM_DESTROY:
                PostQuitMessage(0);
                break;
        }
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
POINT CenterPoint(RECT& r)
{
    POINT p;
    p.x = (r.left + r.right)/2;
    p.y = (r.top + r.bottom)/2;
    return p;
}


/*
  <windef.h>에 보면 다음과 같이 선언
  typedef struct tagPOINT
  {
    LONG x;
    LONG y;
  } POINT;
  typedef struct tagRECT
  {
    LONG left;
    LONG top;
    LONG right;
    LONG bottom;
  } RECT;

  BOOL GetClientRect {
    HWND hWnd,      // handle to window
    LPRECT lpRect   // address of structure for client coordinates
  }

  *) 윈도우 타이틀바를 제외한 전체 영역을 client area 라한다. 이 client area를
     갖다주는 함수가 GetClientRect 함수이다.
  *) 좌표는 언제나 POINT 타입으로 표현된다.
  *) GetTextMetrics() 함수는 시스템 폰트의 크기를 알수있다.

  */