getDC

// 01WM_PAINT与GetDC.cpp : 定义应用程序的入口点。
//

#include "stdafx.h"
#include "01WM_PAINT与GetDC.h"

#define MAX_LOADSTRING 100

#define MYBUTTON1  10001

#define MYBUTTON2  10002

#define MYBUTTON3  10003
// 全局变量: 
HINSTANCE hInst;                                // 当前实例
TCHAR szTitle[MAX_LOADSTRING];                    // 标题栏文本
TCHAR szWindowClass[MAX_LOADSTRING];            // 主窗口类名

// 此代码模块中包含的函数的前向声明: 
ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPTSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

     // TODO:  在此放置代码。
    MSG msg;
    HACCEL hAccelTable;

    // 初始化全局字符串
    LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadString(hInstance, IDC_MY01WM_PAINTGETDC, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // 执行应用程序初始化: 
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_MY01WM_PAINTGETDC));

    // 主消息循环: 
    while (GetMessage(&msg, NULL, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}



//
//  函数:  MyRegisterClass()
//
//  目的:  注册窗口类。
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style            = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra        = 0;
    wcex.cbWndExtra        = 0;
    wcex.hInstance        = hInstance;
    wcex.hIcon            = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_MY01WM_PAINTGETDC));
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground    = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName    = MAKEINTRESOURCE(IDC_MY01WM_PAINTGETDC);
    wcex.lpszClassName    = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassEx(&wcex);
}

//
//   函数:  InitInstance(HINSTANCE, int)
//
//   目的:  保存实例句柄并创建主窗口
//
//   注释: 
//
//        在此函数中，我们在全局变量中保存实例句柄并
//        创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // 将实例句柄存储在全局变量中

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  函数:  WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  目的:    处理主窗口的消息。
//
//  WM_COMMAND    - 处理应用程序菜单
//  WM_PAINT    - 绘制主窗口
//  WM_DESTROY    - 发送退出消息并返回
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;
    static int nNum = 10;
    switch (message)
    {
    case  WM_CREATE:
        //创建按钮用于GetDC()
        CreateWindow(
            TEXT("button"),
            TEXT("hehe"),
            WS_VISIBLE | WS_CHILD,
            50, 50, 60, 30, hWnd,
            (HMENU)MYBUTTON1,
            hInst,
            NULL);
        //创建按钮用于GetWindowDC()
        CreateWindow(
            TEXT("button"),
            TEXT("hehe"),
            WS_VISIBLE | WS_CHILD,
            120, 50, 60, 30, hWnd,
            (HMENU)MYBUTTON2,
            hInst,
            NULL);
        CreateWindow(
            TEXT("button"),
            TEXT("hehe"),
            WS_VISIBLE | WS_CHILD,
            190, 50, 60, 30, hWnd,
            (HMENU)MYBUTTON3,
            hInst,
            NULL);

    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        // 分析菜单选择: 
        switch (wmId)
        {
        case  MYBUTTON1:
        {
            HDC hDc = GetDC(NULL);
            TextOut(hDc, 0, 0, TEXT("15PB"), 4);
            ReleaseDC(hWnd, hDc);
        }
            break;
        case MYBUTTON2:
        {
            HDC hDc = GetWindowDC(hWnd);
            TextOut(hDc, 0, 20, TEXT("15PB"), 4);
        }
            break;
        case  MYBUTTON3:
        {
            HDC hDc = CreateDC(TEXT("DISPLAY"), NULL, NULL, NULL);
            TextOut(hDc, 100, 100, TEXT("15PB"), 4);
        }
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_PAINT:
    {
        hdc = BeginPaint(hWnd, &ps);
        // TODO:  在此添加任意绘图代码...
        //用以验证有效区域和无效区域
        nNum++;
        TCHAR buf[20] = {};
        _stprintf_s(buf, 20, TEXT("%d"), nNum);
        TextOut(hdc, 100, 100, buf, _tcsclen(buf));
        EndPaint(hWnd, &ps);
        break;
    }
    case WM_NCPAINT:
    {
//         HDC hdc;
//         hdc = GetDCEx(hWnd, (HRGN)wParam, DCX_WINDOW | DCX_INTERSECTRGN);
//         TextOut(hdc, 0, 0, TEXT("15PB"), 4);
//         ReleaseDC(hWnd, hdc);
        return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

// “关于”框的消息处理程序。
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}