오너드로우 버튼 (Owner Draw button, WM_DRAWITEM, CreateCompatibleDC, SelectObject, LoadBitmap)

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPSTR lpszClass="OwnerBtn2";

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,
        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;
}

#include "resource.h"
HBITMAP hUp,hDown;
#define ID_OWNERBTN 100
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    HDC hMemDC;
    LPDRAWITEMSTRUCT lpdis;
    switch(iMessage) {
    case WM_CREATE:
        CreateWindow("button",NULL,WS_CHILD | WS_VISIBLE | BS_OWNERDRAW,
            10,10,81,70,hWnd,(HMENU)ID_OWNERBTN,g_hInst,NULL);
        hUp=LoadBitmap(g_hInst,MAKEINTRESOURCE(IDB_BTNUP));
        hDown=LoadBitmap(g_hInst,MAKEINTRESOURCE(IDB_BTNDOWN));
        return 0;
    case WM_DRAWITEM:
        lpdis=(LPDRAWITEMSTRUCT)lParam;
        hMemDC=CreateCompatibleDC(lpdis->hDC);
        if (lpdis->itemState & ODS_SELECTED) {
            SelectObject(hMemDC, hDown);
        } else {
            SelectObject(hMemDC, hUp);
        }
        BitBlt(lpdis->hDC,0,0,81,70,hMemDC,0,0,SRCCOPY);
        DeleteDC(hMemDC);
        return 0;
    case WM_COMMAND:
        switch (LOWORD(wParam)) {
        case ID_OWNERBTN:
            MessageBox(hWnd,"오너 드로우 버튼을 선택했네요","확인",MB_OK);
        }
        return 0;
    case WM_DESTROY:
        DeleteObject(hUp);
        DeleteObject(hDown);
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}