[핵심 API로 배우는 윈도우프로그래밍(강경우, 한빛아카데미)] 4장 5번 풀이

#include <Windows.h>
#include<tchar.h>
#include<string.h>
#include<math.h>
#include"resource.h"
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam);
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    HWND hwnd;
    MSG msg;
 
    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,
        100,
        100,
        1000,
        1000,
        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;
    PAINTSTRUCT ps;
    HPEN hPen;
    HBRUSH hBrush;
    CHOOSECOLOR COLOR;
    static COLORREF temp[16],PenColor=RGB(0,0,0),FaceColor=RGB(255,255,255);
 
    static bool isClick = false;
    static int mX1, mY1,mX2,mY2;
    static int Figure=0;
 
    switch (iMsg)
    {
    case WM_CREATE:
        break;
    case  WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case ID_PENCOLOR:
            for (int i = 0; i < 16; i++)
                temp[i] = RGB(rand() % 256, rand() % 256, rand() % 256);
            memset(&COLOR, 0, sizeof(CHOOSECOLOR));
            COLOR.lStructSize = sizeof(CHOOSECOLOR);
            COLOR.hwndOwner = hwnd;
            COLOR.lpCustColors = temp;
            COLOR.Flags = CC_FULLOPEN;
            if (ChooseColor(&COLOR) != 0)
            {
                PenColor = COLOR.rgbResult;
            }
            break;
        case ID_FACECOLOR:
            for (int i = 0; i < 16; i++)
                temp[i] = RGB(rand() % 256, rand() % 256, rand() % 256);
            memset(&COLOR, 0, sizeof(CHOOSECOLOR));
            COLOR.lStructSize = sizeof(CHOOSECOLOR);
            COLOR.hwndOwner = hwnd;
            COLOR.lpCustColors = temp;
            COLOR.Flags = CC_FULLOPEN;
            if (ChooseColor(&COLOR) != 0)
            {
                FaceColor = COLOR.rgbResult;
            }
            break;
        case ID_LINE:
            Figure = 1;
            break;
        case ID_ELLIPSE:
            Figure = 2;
            break;
        case ID_RECTANGLE:
            Figure = 3;
            break;
        }
        break;
    case WM_LBUTTONDOWN:
        //hdc = GetDC(hwnd);
        isClick = true;
        mX1 = LOWORD(lParam);
        mY1 = HIWORD(lParam);
        //ReleaseDC(hwnd, hdc);
        break;
    case WM_LBUTTONUP:
        hdc = GetDC(hwnd);
        isClick = false;
        hPen = CreatePen(PS_SOLID, 1, PenColor);
        SelectObject(hdc, hPen);
        hBrush = CreateSolidBrush(FaceColor);
        SelectObject(hdc, hBrush);
        mX2 = LOWORD(lParam);
        mY2 = HIWORD(lParam);
        switch (Figure)
        {
        case 1:
            MoveToEx(hdc, mX1, mY1,NULL);
            LineTo(hdc, mX2, mY2);
            break;
        case 2:
            Ellipse(hdc, mX1, mY1, mX2, mY2);
            break;
        case 3:
            Rectangle(hdc, mX1, mY1, mX2, mY2);
            break;
        }
        ReleaseDC(hwnd, hdc);
        break;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
 
        EndPaint(hwnd, &ps);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
 
    }
    return DefWindowProc(hwnd, iMsg, wParam, lParam);
}