키보드,마우스로 스크롤 하기 (panning, ScrollWindow, SetScrollPos, SendMessage, SB_)

#define _WIN32_WINNT 0x500
#include <windows.h>

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

int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
         ,LPSTR lpszCmdParam,int nCmdShow)
{
    HWND hWnd;
    MSG Message;
    WNDCLASS WndClass;
    g_hInst=hInstance;
    
    if(!hPrevInstance) {
        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_HSCROLL | WS_VSCROLL,
         CW_USEDEFAULT,CW_USEDEFAULT,640,480,
         NULL,(HMENU)NULL,hInstance,NULL);
    ShowWindow(hWnd,nCmdShow);
    
    while(GetMessage(&Message,0,0,0)) {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
    return Message.wParam;
}

int yPos,xPos;
int yMax,xMax;
BOOL bCapture;
int Mx,My;
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    int i;
    char str[128];
    HDC hdc;
    PAINTSTRUCT ps;
    int xInc, yInc;
    SCROLLINFO si;
    switch(iMessage) {
    case WM_CREATE:
        xPos=0;
        yPos=0;
        xMax=1024;
        yMax=768;
        return 0;
    // 비례 스크롤 바
    case WM_SIZE:
        si.cbSize=sizeof(SCROLLINFO);
        si.fMask=SIF_ALL | SIF_DISABLENOSCROLL;
        si.nMin=0;
        si.nMax=768;
        si.nPage=HIWORD(lParam);
        si.nPos=yPos;
        SetScrollInfo(hWnd, SB_VERT, &si, TRUE);

        si.nMax=1024;
        si.nPage=LOWORD(lParam);
        si.nPos=xPos;
        SetScrollInfo(hWnd, SB_HORZ, &si, TRUE);
        return 0;
    case WM_HSCROLL:
        xInc=0;
        switch (LOWORD(wParam)) {
        case SB_LINEUP:
            xInc=-1;
            break;
        case SB_LINEDOWN:
            xInc=1;
            break;
        case SB_PAGEUP:
            xInc=-20;
            break;
        case SB_PAGEDOWN:
            xInc=20;
            break;
        case SB_THUMBTRACK:
            xInc=HIWORD(wParam)-xPos;
            break;
        default:
            break;
        }
        // 새로운 위치는 최소한 0 이상
        if (xPos+xInc < 0)
            xInc=-xPos;
        // 새로운 위치는 최대한 xMax 이하
        if (xPos+xInc > xMax)
            xInc=xMax-xPos;
        // 새로운 위치 계산
        xPos=xPos+xInc;
        // 스크롤시키고 썸 위치를 다시 계산한다.
        ScrollWindow(hWnd, -xInc, 0, NULL, NULL);
        SetScrollPos(hWnd, SB_HORZ, xPos, TRUE);
        return 0;
    case WM_VSCROLL:
        yInc=0;
        switch (LOWORD(wParam)) {
        case SB_LINEUP:
            yInc=-1;
            break;
        case SB_LINEDOWN:
            yInc=1;
            break;
        case SB_PAGEUP:
            yInc=-20;
            break;
        case SB_PAGEDOWN:
            yInc=20;
            break;
        case SB_THUMBTRACK:
            yInc=HIWORD(wParam)-yPos;
            break;
        default:
            break;
        }
        // 새로운 위치는 최소한 0 이상
        if (yPos+yInc < 0)
            yInc=-yPos;
        // 새로운 위치는 최대한 yMax 이하
        if (yPos+yInc > yMax)
            yInc=yMax-yPos;
        // yInc=max(-yPos, min(yInc, yMax-yPos));
        // 새로운 위치 계산
        yPos=yPos+yInc;
        // 스크롤시키고 썸 위치를 다시 계산한다.
        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<1024;i+=50) {
            wsprintf(str,"%d",i);
            TextOut(hdc,i-xPos,0-yPos,str,strlen(str));
            TextOut(hdc,i-xPos,750-yPos,str,strlen(str));
        }
        for (i=0;i<768;i+=50) {
            wsprintf(str,"%d",i);
            TextOut(hdc,0-xPos,i-yPos,str,strlen(str));
            TextOut(hdc,1000-xPos,i-yPos,str,strlen(str));
        }
        MoveToEx(hdc,500-xPos,100-yPos,NULL);
        LineTo(hdc,500-xPos,668-yPos);
        MoveToEx(hdc,100-xPos,380-yPos,NULL);
        LineTo(hdc,924-xPos,380-yPos);
        Ellipse(hdc,200-xPos,200-yPos,800-xPos,500-yPos);
        EndPaint(hWnd, &ps);
        return 0;
    // 키보드 지원
    case WM_KEYDOWN:
        switch (wParam) {
        case VK_UP:
            SendMessage(hWnd, WM_VSCROLL, MAKELONG(SB_PAGEUP,0),0);
            break;
        case VK_DOWN:
            SendMessage(hWnd, WM_VSCROLL, MAKELONG(SB_PAGEDOWN,0),0);
            break;
        case VK_LEFT:
            SendMessage(hWnd, WM_HSCROLL, MAKELONG(SB_PAGEUP,0),0);
            break;
        case VK_RIGHT:
            SendMessage(hWnd, WM_HSCROLL, MAKELONG(SB_PAGEDOWN,0),0);
            break;
        }
        return 0;
    // 왼쪽 버튼을 누르면 패닝을 시작한다.
    case WM_LBUTTONDOWN:
        Mx=LOWORD(lParam);
        My=HIWORD(lParam);
        bCapture=TRUE;
        SetCapture(hWnd);
        return 0;
    // 마우스를 누른채로 이동하면 스크롤 시킨다.
    case WM_MOUSEMOVE:
        if (bCapture == TRUE) {
            int Nx, Ny;
            // 현재 마우스 위치 계산
            Nx=(int)(short)LOWORD(lParam);
            Ny=(int)(short)HIWORD(lParam);

            // y증가값 계산
            yInc=My-Ny;
            if (yPos+yInc < 0) yInc=-yPos;
            if (yPos+yInc > yMax) yInc=yMax-yPos;
            yPos=yPos+yInc;

            // x증가값 계산
            xInc=Mx-Nx;
            if (xPos+xInc < 0) xInc=-xPos;
            if (yPos+xInc > xMax) xInc=xMax-xPos;
            xPos=xPos+xInc;

            // 스크롤 및 스크롤 바 위치 갱신
            ScrollWindow(hWnd,-xInc,-yInc,NULL,NULL);
            SetScrollPos(hWnd,SB_VERT,yPos,TRUE);
            SetScrollPos(hWnd,SB_HORZ,xPos,TRUE);

            // 현재 위치 저장
            My=Ny;
            Mx=Nx;
        }
        return 0;
    // 패닝 종료
    case WM_LBUTTONUP:
        bCapture=FALSE;
        ReleaseCapture();
        return 0;
    case WM_MOUSEWHEEL:
        MessageBeep(0);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}