[핵심 API로 배우는 윈도우프로그래밍(강경우, 한빛아카데미)] 5장 8번 풀이

#include <Windows.h>
#include<tchar.h>
#include<string.h>
#include<math.h>
#include<stdio.h>
#include"resource.h"
#pragma comment(linker,"/entry:WinMainCRTStartup /subsystem:console")
 
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam);
HINSTANCE hInst;
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    HWND hwnd;
    MSG msg;
    hInst = hInstance;
    WNDCLASS WndClass;
    WndClass.style = CS_HREDRAW | CS_VREDRAW;
    WndClass.lpfnWndProc = WndProc;
    WndClass.cbClsExtra = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hInstance = hInstance;
    WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    WndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    WndClass.lpszMenuName = NULL;
    WndClass.lpszClassName = _T("Window Class Name");
    WndClass.lpszMenuName = MAKEINTRESOURCE(IDR_MENU1);
    RegisterClass(&WndClass);
 
    hwnd = CreateWindow(
        _T("Window Class Name"),
        _T("홍길동의 첫 번째 윈도우"),
        WS_OVERLAPPEDWINDOW,
        50,
        50,
        1000,
        700,
        NULL,
        NULL,
        hInstance,
        NULL);
 
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
 
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}
 
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
    HDC hdc, mem1dc;
    PAINTSTRUCT ps;
    HPEN hPen, oldPen;
    static HBITMAP hBit, oldBit;
    static int BY = 1;
    static bool DUP = false;
    static int posX[5], posY[5];
    switch (iMsg)
    {
    case WM_CREATE:
        hBit = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP5));
        break;
 
    case WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case ID_3BY3:
            BY = 3;
            break;
        case ID_4BY4:
            BY = 4;
            break;
        case ID_5BY5:
            BY = 5;
            break;
        }
        InvalidateRgn(hwnd, NULL, TRUE);
        break;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        mem1dc = CreateCompatibleDC(hdc);
        oldBit = (HBITMAP)SelectObject(mem1dc, hBit);
        switch (BY)
        {
        case 3:
            posX[0] = 1; posX[1] = 0; posX[2] = 2;
            posY[0] = 0; posY[1] = 2; posY[2] = 1;
            break;
        case 4:
            posX[0] = 1; posX[1] = 0; posX[2] = 3; posX[3] = 2;
            posY[0] = 3; posY[1] = 2; posY[2] = 1; posY[3] = 0;
            break;
        case 5:
            posX[0] = 1; posX[1] = 0; posX[2] = 3; posX[3] = 2; posX[4] = 4;
            posY[0] = 4; posY[1] = 2; posY[2] = 1; posY[3] = 3; posY[4] = 0;
            break;
        }
 
        for (int i = 0; i < BY; i++)
        {
            for (int j = 0; j < BY; j++)
            {
                BitBlt(hdc, i * (819.0f / BY), j * (614.0f / BY), 819.0f / BY, 614.0f / BY, mem1dc, (819.0f / BY)*posX[i], (614.0f / BY)*posY[j], SRCCOPY);
            }
        }
        SelectObject(mem1dc, hBit);
        DeleteDC(mem1dc);
        EndPaint(hwnd, &ps);
        break;
    case WM_DESTROY:
        DeleteObject(hBit);
        PostQuitMessage(0);
        break;
 
    }
    return DefWindowProc(hwnd, iMsg, wParam, lParam);
}