마우스로 사각형 움직이기

전체적인 구조의 코드는 너무 기니깐, LRESULT CALLBACK WndProc()함수의 코드만 적도록 하겠다...

//전역변수

int g_is_clicked = 0;
RECT g_rect = { 50, 50, 50, 50 };
POINT g_prev_pos;

 

LREULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
if(uMsg == MW_DESTROY)PostQuitMessage(0);

else if(uMsg == WM_PAINT){

PAINTSTRUCT ps;

HDC h_dc = BeginPaint(hWnd,&ps);

 

Rectangle(h_dc,g_rect.left,g_rect.top,g_rect.right,g_rect.bottom);

 

EndPaint(hWnd,&ps);

return 0;

}

else if(uMsg == WM_LBUTTONDOWN){

g_is_clicked = 1;

g_prev_pos.x = LOWORD(lParam);

g_prev_pos.y = HIWORD(lParam);

 

if(g_prev_pos.x <= g_rect.right && g_prev_pos.x>=g_rect.left&&

g_prev_pos.y <=g_rect.top && g_prev_pos.y >=g_rect.bottom){

g_is_clicked = 1;

SetCapture(hWnd); //사각형이 클라이언트(유효화영역)에서 나가도 마우스로 움직일수 있게 해주는 API함수

}

}

else if(uMsg == WM_LBUTTONUP){
g_is_clicked = 0;

ReleaseCapture();

}

else if(uMsg == WM_MOUSEMOVE){

if(g_is_clicked){

int x = LOWORD(lParam);

int y = HIWORD(lParam);

 

int h_interval  = x - g_prev_pos.x;

int v_interval = y - g_prev_pos.y;

 

g_rect.left += h_interval;

g_rect.right += h_interval;

g_rect.top += v_interval;

h_interval.bottom += v_interval;

 

g_prev_pos.x = x;

g_prev_pos.y = y;

 

InvalidateRect(hWnd,NULL,TRUE);

}

}

return DefWindowProc(hWnd,uMsg,wParam,lParam);

}