走进windows编程的世界-----消息处理函数（2）

一 WM_PAINT消息

 1 WM_PAINT的产生
   由于窗口的互相覆盖等,产生需要绘制的区域,那么会产生WM_PAINT消息.
   一般情况下,不直接发送WM_PAINT消息,通过API声明需要绘制区域,来产生WM_PAINT消息.
   例如,可以使用InvalidateRect声明一个需要重新绘制的区域.
  
  2 WM_PAINT的注意点
    2.1 如果一个消息队列中,有多个WM_PAINT消息,只有最后一个WM_PAINT消息会被处理.
    2.2 WM_PAINT消息处理中,要清空需要被绘制的区域. BeginPaint
      
  3 WM_PAINT的使用
    3.1 WM_PAINT开始时,必须调用BeginPaint
    3.2 绘制图形
    3.3 WM_PAINT处理后,必须调用EndPaint

 看下面的示例代码：

/* File : winpaint.cpp
 * Auth : sjin
 * Date : 20140706
 * Mail : 413977243@qq.com
 */

#include <Windows.h>
#include <stdio.h>


HINSTANCE g_hInst = NULL;

void OnPaint(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
    PAINTSTRUCT ps = {0};
	/*WM_PAINT开始时，必须调用的*/
    HDC hDC = BeginPaint(hWnd, &ps);

    CHAR szText[] = "Hello WM_PAINT";
	/*在指定的坐标下输出一行字*/
    TextOut(hDC, 100, 100, szText, strlen(szText));

	/*绘制一个矩形*/
    Rectangle(hDC, 200, 200, 300, 300);

	EndPaint(hWnd,&ps);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
    switch(nMsg)
    {
    case WM_PAINT:
        OnPaint(hWnd, nMsg, wParam, lParam); 
		break;
    case WM_DESTROY:
        PostQuitMessage(0); 
		return 0;
    }
    return DefWindowProc(hWnd, nMsg, wParam, lParam);
}

BOOL RegisterWnd(LPSTR lpszClassName)
{
    WNDCLASSEX wce = {0};
    wce.cbClsExtra = 0;
    wce.cbSize = sizeof(wce);
    wce.cbWndExtra = 0;
    wce.hbrBackground = HBRUSH(COLOR_BTNFACE + 1);
    wce.hCursor = NULL;
    wce.hIcon = NULL;
    wce.hIconSm = NULL;
    wce.hInstance = g_hInst;
    wce.lpfnWndProc = WndProc;
    wce.lpszClassName = lpszClassName;
    wce.lpszMenuName = NULL;
    wce.style = CS_HREDRAW|CS_VREDRAW;

    ATOM nAtom = RegisterClassEx(&wce);
    if(0 == nAtom)
    {
        return FALSE;
    }
    return TRUE;
}

HWND CreateWnd(LPSTR lpszClassName)
{
    HWND hWnd = CreateWindowEx(0,
        lpszClassName, "MyWndPaint", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, g_hInst, NULL);
    return hWnd;
}

void DisplayWnd(HWND hWnd)
{
    ShowWindow(hWnd, SW_SHOW);
    UpdateWindow(hWnd);
}

void Message()
{
    MSG msg = {0};
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
     g_hInst = hInstance;
    RegisterWnd("MyWndPaint");
    HWND hWnd = CreateWnd("MyWndPaint");
    DisplayWnd(hWnd);
    Message();
    return 0;
}

三 键盘消息

  1 键盘消息
   按键消息
     WM_KEYDOWN 当键被按下时产生
     WM_KEYUP 当键被释放时产生
     WM_SYSKEYDOWN 当系统键被按下时产生 ALT/F10
     WM_SYSKEYUP 当系统键释放时产生
    字符消息
     WM_CHAR 当有字符键被按下时产生
      TranslateMessage会将WM_KEYDOWN消息中,可以显示的按键,转换成WM_CHAR的消息
  2 消息参数
    WPARAM - 虚拟键码
    LPARAM - 相关的按键信息.
  
  3 消息的使用
    3.1 当有按键消息时,首先进入系统消息队列,然后被程序的消息循环获取.
    3.2 消息的处理
  4 键盘消息的顺序
    对于可显示字符: WM_KEYDOWN,WM_CHAR,WM_KEYUP
    对于不可显示字符: WM_KEYDOWN,WM_KEYUP
    对于系统键:WM_SYSKEYDOWN,WM_SYSKEYUP
    如果按键一直不释放,会重复产生
         WM_KEYDOWN(WM_CHAR)

/* File : winKeyboard.cpp
 * Auth : sjin
 * Date : 2014-07-06
 * Mail : 413977243@qq.com
 */

#include <Windows.h>
#include <stdio.h>


HINSTANCE g_hInst = NULL;
HANDLE g_hStdOut = NULL;

LRESULT CALLBACK WinProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
    switch(nMsg)
    {
    case WM_KEYDOWN:/*键盘按下*/
        {
            CHAR szText[] = "WM_KEYDOWN
";
            switch(wParam)
            {
            case VK_LEFT:
            case VK_RIGHT:
            case VK_UP:
            case VK_DOWN:
                WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL);
                break;
            }
        }
        break;
    case WM_KEYUP:/*键盘抬起*/
        {
            CHAR szText[] = "WM_KEYUP
";
            WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL); break;
        }
        break;
    case WM_SYSKEYDOWN:/*系统键按下*/
        {
            CHAR szText[] = "WM_SYSKEYDOWN
";
            WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL); break;
        }
        break;
    case WM_SYSKEYUP:/*系统键抬起*/
        {
            CHAR szText[] = "WM_SYSKEYUP
";
            WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL); break;
        }
        break; 
    case WM_CHAR:/*字符键盘*/
        {
            CHAR szText[260] = {0};
            sprintf(szText, "WM_CHAR: %c
", wParam);
            WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL); break;
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0); return 0;
    }
    return DefWindowProc(hWnd, nMsg, wParam, lParam);
}

BOOL ResiterWnd(LPSTR lpszClassName)
{
    WNDCLASSEX wce = {0};
    wce.cbClsExtra = 0;
    wce.cbSize = sizeof(wce);
    wce.cbWndExtra = 0;
    wce.hbrBackground = HBRUSH(COLOR_BTNFACE+1);
    wce.hCursor = NULL;
    wce.hIcon = NULL;
    wce.hIconSm = NULL;
    wce.hInstance = g_hInst;
    wce.lpfnWndProc = WinProc;
    wce.lpszClassName = lpszClassName;
    wce.lpszMenuName = NULL;
    wce.style = CS_HREDRAW|CS_VREDRAW;

    ATOM nAtom = RegisterClassEx(&wce);
    if(0==nAtom)
    {
        return FALSE;
    }
    return TRUE;
}

HWND CreateWnd(LPSTR lpszClassName)
{
    HWND hWnd = CreateWindowEx(0, lpszClassName, "MyWnd",
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,CW_USEDEFAULT,
        NULL, NULL, g_hInst, NULL);
    return hWnd;
}

void ShowWnd(HWND hWnd)
{
    ShowWindow(hWnd, SW_SHOW);
    UpdateWindow(hWnd);
}

void Message()
{
    MSG msg = {0};
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

void NewConsole()
{
	/*产生控制台*/
    AllocConsole();

	/*获得控制台标准输出流句柄*/
    g_hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
    CHAR szText[] = "Debug Message......:
";
	/*将szText 写到控制台*/
    WriteConsole(g_hStdOut, szText, strlen(szText), NULL, NULL);
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
	/*产生命令行窗口，用来调试程序*/
    NewConsole();
     g_hInst = hInstance;
    ResiterWnd("MyWnd");
    HWND hWnd = CreateWnd("MyWnd");
    ShowWnd(hWnd);
    Message();

    return 0;
}

三  鼠标消息

  1 鼠标消息
    1) 基本鼠标消息
    WM_LBUTTONDOWN   左键按下
    WM_LBUTTONUP     左键抬起
    WM_RBUTTONDOWN   右键按下
    WM_RBUTTONUP     右键抬起
    WM_MOUSEMOVE     鼠标移动
    2) 双击消息
    WM_LBUTTONDBLCLK 左键双击 
    WM_RBUTTONDBLCLK 右键双击
    3) 滚轮消息
    WM_MOUSEWHEEL    鼠标滚轮

  2 消息的参数
    WPARAM - 当前键盘和鼠标按键状态，例如MK_CONTROL/MK_SHIFT,MK_LBUTTON等
    LPARAM - 当前鼠标的坐标,坐标的原点是窗口客户区的左上角.
       X坐标 - LOWORD(lParam),低16位
       Y坐标 - HIWORD(lParam),高16位
    参数具体内容和具体鼠标消息有稍微不同. 
    
  3 消息的使用
  
    3.1 基本鼠标消息,只需在窗口处理函数增加消息处理即可. 当消息来临,获取鼠标和按键状态.例如:

case WM_MOUSEMOVE:
{
    int nX = LOWORD(lParam);
    int nY = HIWORD(lParam);
}