특정영역만 스크롤하기 (ScrollWindow, GetClientRect, scrollbar, SetScrollRange, SetScrollPos)

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPSTR lpszClass="ScrRect";

int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
         ,LPSTR lpszCmdParam,int nCmdShow)
{
    HWND hWnd;
    MSG Message;
    WNDCLASS WndClass;
    g_hInst=hInstance;
    
    WndClass.cbClsExtra=0;
    WndClass.cbWndExtra=0;
    WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
    WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
    WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    WndClass.hInstance=hInstance;
    WndClass.lpfnWndProc=(WNDPROC)WndProc;
    WndClass.lpszClassName=lpszClass;
    WndClass.lpszMenuName=NULL;
    WndClass.style=CS_HREDRAW | CS_VREDRAW;
    RegisterClass(&WndClass);

    hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW |
        WS_VSCROLL,
        CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
        NULL,(HMENU)NULL,hInstance,NULL);
    ShowWindow(hWnd,nCmdShow);
    
    while(GetMessage(&Message,0,0,0)) {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
    return Message.wParam;
}

int yPos;
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    int i;
    char str[128];
    int yInc;
    RECT crt,rt;
    switch(iMessage) {
    case WM_CREATE:
        CreateWindow("button","?1",WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
            20,20,100,25,hWnd,(HMENU)0,g_hInst,NULL);
        CreateWindow("button","?2",WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
            20,50,100,25,hWnd,(HMENU)1,g_hInst,NULL);
        SetScrollRange(hWnd, SB_VERT, 0, 100*20, TRUE);
        SetScrollPos(hWnd, SB_VERT, 0, TRUE);
        return 0;
    case WM_VSCROLL:
        yInc=0;
        switch (LOWORD(wParam)) {
        case SB_LINEUP:
            yInc=-20;
            break;
        case SB_LINEDOWN:
            yInc=20;
            break;
        case SB_PAGEUP:
            yInc=-200;
            break;
        case SB_PAGEDOWN:
            yInc=200;
            break;
        case SB_THUMBTRACK:
            yInc=HIWORD(wParam)-yPos;
            break;
        default:
            break;
        }
        if (yPos+yInc < 0)
            yInc=-yPos;
        if (yPos+yInc > 20*100)
            yInc=20*100-yPos;
        yPos=yPos+yInc;
        GetClientRect(hWnd,&crt);
        SetRect(&rt,150,100,crt.right,200);//crt.bottom);
        ScrollWindow(hWnd, 0, -yInc, &rt, &rt);
//        ScrollWindowEx(hWnd, 0, -yInc, &rt, &rt);        // 32bit
//        ScrollWindow(hWnd, 0, -yInc, NULL, NULL);
        SetScrollPos(hWnd, SB_VERT, yPos, TRUE);
        return 0;
    case WM_PAINT:
        hdc=BeginPaint(hWnd, &ps);
        for (i=0;i<100;i++) {
            wsprintf(str,"Line Number : %d",i);
            TextOut(hdc,150,i*20-yPos,str,strlen(str));
        }
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}