32비트 스크롤바 (GetScrollInfo, SCROLLINFO)

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPSTR lpszClass="Scroll32";

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_CLIPCHILDREN,
        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;
}

#define ID_SCROLL 100
HWND hScroll;
int Value;
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    char str[128];
    SCROLLINFO si;                // 스크롤바 구조체
    switch(iMessage) {
    case WM_CREATE:
        hScroll=CreateWindow("scrollbar",NULL,WS_CHILD | WS_VISIBLE | SBS_HORZ,
            10,100,600,20,hWnd,(HMENU)ID_SCROLL,g_hInst,NULL);
        Value=60000;
        SetScrollRange(hScroll,SB_CTL,0,123456,TRUE);
        SetScrollPos(hScroll,SB_CTL,Value,TRUE);
        return 0;
    case WM_HSCROLL:
        switch (LOWORD(wParam)) {
        case SB_LINELEFT:
            Value=max(0,Value-10);
            break;
        case SB_LINERIGHT:
            Value=min(123456,Value+10);
            break;
        case SB_PAGELEFT:
            Value=max(0,Value-1000);
            break;
        case SB_PAGERIGHT:
            Value=min(123456,Value+1000);
            break;
        case SB_THUMBTRACK:
            si.cbSize=sizeof(SCROLLINFO);
            si.fMask=SIF_TRACKPOS;
            GetScrollInfo(hScroll,SB_CTL,&si);    // wParam 은 UINT 16bit 인데 스크롤바는 32bit이므로 변환과정이 필요하다.
            Value=si.nTrackPos;
            //Value=HIWORD(wParam);
            break;
        }
        SetScrollPos((HWND)lParam,SB_CTL,Value,TRUE);
        InvalidateRect(hWnd,NULL,TRUE);
        return 0;
    case WM_PAINT:
        hdc=BeginPaint(hWnd, &ps);
        wsprintf(str,"Value is %d",Value);
        TextOut(hdc,50,50,str,strlen(str));
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}