本文介绍了Windows系统中键盘消息的处理机制，包括按键消息与字符消息的区别及处理流程。详细解析了TranslateMessage函数如何将按键消息转化为字符消息，以及DispatchMessage如何发送这些消息到窗口。此外，还提供了两个示例程序，分别演示了按键消息处理和字符消息处理的方法。
键盘是windows的基础输入设备，用户通过键盘可以通过键盘上的按键来控制系统与输入内容。为满足键盘的这两个功能要求系统将键盘产生的消息区分为按键消息和字符消息（当然具体处理的时候并没有严格限定按键消息只能用于控制系统，字符消息只能用于输入文字，用户自定义处理可以识别按键信息用于输入，使用字符信息用于控制）。
按键消息有系统按键消息和普通按键消息，系统按键消息经常由与Alt 相组合的按键产生，按下（Down）和释放（Up）消息通常是成对产生的。
对于系统而言就只存在按键消息，系统接收到按键消息之后放入到程序的消息队列中，GetMessage函数获取的按键消息后，通过TransMessage，将按键消息转化为字符消息，再放入到消息队列的最前端，字符消息通常被夹在keydown和keyup消息之间：
对于按键消息的内容，必然指定了键盘中被按下的是那一个键。有些键盘中的键的扫描码是不相同的，windows为了消除这些区别使用虚拟码来表示所有这些键盘上不同的键，使得程序员只需要处理输入的内容而不必关心按下键的扫描码代表的是哪个字符。Message的wParam用于表示虚拟键码。
而Msg的lParam则携带如下信息：
大部分的信息都可以忽略，只有在检测是否同时按下了alt键或者shift键的时候才会有用。
对于按键消息系统会调用TranslateMessage函数，将按键消息转换为字符消息用于输入内容。系统会根据目标对象是通过RegisterClassA还是RegisterClassW注册的类来将字符转化ANSI或Unicode的字符，保存在Msg的wParam参数中。
字符消息和按键消息最终都会被DispatchMessage发送到窗口或者窗口中具有焦点的子窗口中，字符消息中携带的字符code与系统的文字版本相关，不过大部分不需要关系。对于用于接收文字输入的子窗口通常需要有个插入符来表示文字输入的位置。一般而言一个程序之中只有一个子窗口会获得焦点，故而只有在获得焦点的时候创建插入符号而失去焦点的时候删除插入符号。
以下有两个程序风别表现按键消息处理和字符消息处理：
/*-----------------------------------------------
SYSMETS.H -- System metrics display structure
-----------------------------------------------*/
#define NUMLINES ((int) (sizeof sysmetrics / sizeof sysmetrics [0]))
struct
{
int iIndex ;
TCHAR * szLabel ;
TCHAR * szDesc ;
}
sysmetrics [] =
{
SM_CXSCREEN, TEXT ("SM_CXSCREEN"),
TEXT ("Screen width in pixels"),
SM_CYSCREEN, TEXT ("SM_CYSCREEN"),
TEXT ("Screen height in pixels"),
SM_CXVSCROLL, TEXT ("SM_CXVSCROLL"),
TEXT ("Vertical scroll width"),
SM_CYHSCROLL, TEXT ("SM_CYHSCROLL"),
TEXT ("Horizontal scroll height"),
SM_CYCAPTION, TEXT ("SM_CYCAPTION"),
TEXT ("Caption bar height"),
SM_CXBORDER, TEXT ("SM_CXBORDER"),
TEXT ("Window border width"),
SM_CYBORDER, TEXT ("SM_CYBORDER"),
TEXT ("Window border height"),
SM_CXFIXEDFRAME, TEXT ("SM_CXFIXEDFRAME"),
TEXT ("Dialog window frame width"),
SM_CYFIXEDFRAME, TEXT ("SM_CYFIXEDFRAME"),
TEXT ("Dialog window frame height"),
SM_CYVTHUMB, TEXT ("SM_CYVTHUMB"),
TEXT ("Vertical scroll thumb height"),
SM_CXHTHUMB, TEXT ("SM_CXHTHUMB"),
TEXT ("Horizontal scroll thumb width"),
SM_CXICON, TEXT ("SM_CXICON"),
TEXT ("Icon width"),
SM_CYICON, TEXT ("SM_CYICON"),
TEXT ("Icon height"),
SM_CXCURSOR, TEXT ("SM_CXCURSOR"),
TEXT ("Cursor width"),
SM_CYCURSOR, TEXT ("SM_CYCURSOR"),
TEXT ("Cursor height"),
SM_CYMENU, TEXT ("SM_CYMENU"),
TEXT ("Menu bar height"),
SM_CXFULLSCREEN, TEXT ("SM_CXFULLSCREEN"),
TEXT ("Full screen client area width"),
SM_CYFULLSCREEN, TEXT ("SM_CYFULLSCREEN"),
TEXT ("Full screen client area height"),
SM_CYKANJIWINDOW, TEXT ("SM_CYKANJIWINDOW"),
TEXT ("Kanji window height"),
SM_MOUSEPRESENT, TEXT ("SM_MOUSEPRESENT"),
TEXT ("Mouse present flag"),
SM_CYVSCROLL, TEXT ("SM_CYVSCROLL"),
TEXT ("Vertical scroll arrow height"),
SM_CXHSCROLL, TEXT ("SM_CXHSCROLL"),
TEXT ("Horizontal scroll arrow width"),
SM_DEBUG, TEXT ("SM_DEBUG"),
TEXT ("Debug version flag"),
SM_SWAPBUTTON, TEXT ("SM_SWAPBUTTON"),
TEXT ("Mouse buttons swapped flag"),
SM_CXMIN, TEXT ("SM_CXMIN"),
TEXT ("Minimum window width"),
SM_CYMIN, TEXT ("SM_CYMIN"),
TEXT ("Minimum window height"),
SM_CXSIZE, TEXT ("SM_CXSIZE"),
TEXT ("Min/Max/Close button width"),
SM_CYSIZE, TEXT ("SM_CYSIZE"),
TEXT ("Min/Max/Close button height"),
SM_CXSIZEFRAME, TEXT ("SM_CXSIZEFRAME"),
TEXT ("Window sizing frame width"),
SM_CYSIZEFRAME, TEXT ("SM_CYSIZEFRAME"),
TEXT ("Window sizing frame height"),
SM_CXMINTRACK, TEXT ("SM_CXMINTRACK"),
TEXT ("Minimum window tracking width"),
SM_CYMINTRACK, TEXT ("SM_CYMINTRACK"),
TEXT ("Minimum window tracking height"),
SM_CXDOUBLECLK, TEXT ("SM_CXDOUBLECLK"),
TEXT ("Double click x tolerance"),
SM_CYDOUBLECLK, TEXT ("SM_CYDOUBLECLK"),
TEXT ("Double click y tolerance"),
SM_CXICONSPACING, TEXT ("SM_CXICONSPACING"),
TEXT ("Horizontal icon spacing"),
SM_CYICONSPACING, TEXT ("SM_CYICONSPACING"),
TEXT ("Vertical icon spacing"),
SM_MENUDROPALIGNMENT, TEXT ("SM_MENUDROPALIGNMENT"),
TEXT ("Left or right menu drop"),
SM_PENWINDOWS, TEXT ("SM_PENWINDOWS"),
TEXT ("Pen extensions installed"),
SM_DBCSENABLED, TEXT ("SM_DBCSENABLED"),
TEXT ("Double-Byte Char Set enabled"),
SM_CMOUSEBUTTONS, TEXT ("SM_CMOUSEBUTTONS"),
TEXT ("Number of mouse buttons"),
SM_SECURE, TEXT ("SM_SECURE"),
TEXT ("Security present flag"),
SM_CXEDGE, TEXT ("SM_CXEDGE"),
TEXT ("3-D border width"),
SM_CYEDGE, TEXT ("SM_CYEDGE"),
TEXT ("3-D border height"),
SM_CXMINSPACING, TEXT ("SM_CXMINSPACING"),
TEXT ("Minimized window spacing width"),
SM_CYMINSPACING, TEXT ("SM_CYMINSPACING"),
TEXT ("Minimized window spacing height"),
SM_CXSMICON, TEXT ("SM_CXSMICON"),
TEXT ("Small icon width"),
SM_CYSMICON, TEXT ("SM_CYSMICON"),
TEXT ("Small icon height"),
SM_CYSMCAPTION, TEXT ("SM_CYSMCAPTION"),
TEXT ("Small caption height"),
SM_CXSMSIZE, TEXT ("SM_CXSMSIZE"),
TEXT ("Small caption button width"),
SM_CYSMSIZE, TEXT ("SM_CYSMSIZE"),
TEXT ("Small caption button height"),
SM_CXMENUSIZE, TEXT ("SM_CXMENUSIZE"),
TEXT ("Menu bar button width"),
SM_CYMENUSIZE, TEXT ("SM_CYMENUSIZE"),
TEXT ("Menu bar button height"),
SM_ARRANGE, TEXT ("SM_ARRANGE"),
TEXT ("How minimized windows arranged"),
SM_CXMINIMIZED, TEXT ("SM_CXMINIMIZED"),
TEXT ("Minimized window width"),
SM_CYMINIMIZED, TEXT ("SM_CYMINIMIZED"),
TEXT ("Minimized window height"),
SM_CXMAXTRACK, TEXT ("SM_CXMAXTRACK"),
TEXT ("Maximum dragable width"),
SM_CYMAXTRACK, TEXT ("SM_CYMAXTRACK"),
TEXT ("Maximum dragable height"),
SM_CXMAXIMIZED, TEXT ("SM_CXMAXIMIZED"),
TEXT ("Width of maximized window"),
SM_CYMAXIMIZED, TEXT ("SM_CYMAXIMIZED"),
TEXT ("Height of maximized window"),
SM_NETWORK, TEXT ("SM_NETWORK"),
TEXT ("Network present flag"),
SM_CLEANBOOT, TEXT ("SM_CLEANBOOT"),
TEXT ("How system was booted"),
SM_CXDRAG, TEXT ("SM_CXDRAG"),
TEXT ("Avoid drag x tolerance"),
SM_CYDRAG, TEXT ("SM_CYDRAG"),
TEXT ("Avoid drag y tolerance"),
SM_SHOWSOUNDS, TEXT ("SM_SHOWSOUNDS"),
TEXT ("Present sounds visually"),
SM_CXMENUCHECK, TEXT ("SM_CXMENUCHECK"),
TEXT ("Menu check-mark width"),
SM_CYMENUCHECK, TEXT ("SM_CYMENUCHECK"),
TEXT ("Menu check-mark height"),
SM_SLOWMACHINE, TEXT ("SM_SLOWMACHINE"),
TEXT ("Slow processor flag"),
SM_MIDEASTENABLED, TEXT ("SM_MIDEASTENABLED"),
TEXT ("Hebrew and Arabic enabled flag"),
SM_MOUSEWHEELPRESENT, TEXT ("SM_MOUSEWHEELPRESENT"),
TEXT ("Mouse wheel present flag"),
SM_XVIRTUALSCREEN, TEXT ("SM_XVIRTUALSCREEN"),
TEXT ("Virtual screen x origin"),
SM_YVIRTUALSCREEN, TEXT ("SM_YVIRTUALSCREEN"),
TEXT ("Virtual screen y origin"),
SM_CXVIRTUALSCREEN, TEXT ("SM_CXVIRTUALSCREEN"),
TEXT ("Virtual screen width"),
SM_CYVIRTUALSCREEN, TEXT ("SM_CYVIRTUALSCREEN"),
TEXT ("Virtual screen height"),
SM_CMONITORS, TEXT ("SM_CMONITORS"),
TEXT ("Number of monitors"),
SM_SAMEDISPLAYFORMAT, TEXT ("SM_SAMEDISPLAYFORMAT"),
TEXT ("Same color format flag")
} ;
/*----------------------------------------------------
SYSMETS4.C -- System Metrics Display Program No. 4
(c) Charles Petzold, 1998
----------------------------------------------------*/
#define WINVER 0x0500
#include <windows.h>
#include "sysmets.h"
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
//主函数建立处理框架
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("SysMets4") ;
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 = szAppName ;
if (!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT ("Program requires Windows NT!"),
szAppName, MB_ICONERROR) ;
return 0 ;
}
hwnd = CreateWindow (szAppName, TEXT ("Get System Metrics No. 4"),
WS_OVERLAPPEDWINDOW | WS_VSCROLL | WS_HSCROLL,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static int cxChar, cxCaps, cyChar, cxClient, cyClient, iMaxWidth ;
HDC hdc ;
int i, x, y, iVertPos, iHorzPos, iPaintBeg, iPaintEnd ;
PAINTSTRUCT ps ;
SCROLLINFO si ;
TCHAR szBuffer[10] ;
TEXTMETRIC tm ;
switch (message)
{
case WM_CREATE:
hdc = GetDC (hwnd) ;
//获取文字尺寸
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ; //均宽
cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2) * cxChar / 2 ; //大写宽度
cyChar = tm.tmHeight + tm.tmExternalLeading ; //字高
ReleaseDC (hwnd, hdc) ;
//最大宽度
iMaxWidth = 40 * cxChar + 22 * cxCaps ;
return 0 ;
case WM_SIZE:
cxClient = LOWORD (lParam) ;
cyClient = HIWORD (lParam) ;
//设置纵向滚动条信息，范围和一页的大小
si.cbSize = sizeof (si) ;
si.fMask = SIF_RANGE | SIF_PAGE ;
si.nMin = 0 ;
si.nMax = NUMLINES - 1 ;
si.nPage = cyClient / cyChar ;
SetScrollInfo (hwnd, SB_VERT, &si, TRUE) ;
//设置横向滚动条信息，范围和一页的大小
si.cbSize = sizeof (si) ;
si.fMask = SIF_RANGE | SIF_PAGE ;
si.nMin = 0 ;
si.nMax = 2 + iMaxWidth / cxChar ;
si.nPage = cxClient / cxChar ;
SetScrollInfo (hwnd, SB_HORZ, &si, TRUE) ;
return 0 ;
case WM_VSCROLL:
//获取纵向滚动条信息
si.cbSize = sizeof (si) ;
si.fMask = SIF_ALL ;
GetScrollInfo (hwnd, SB_VERT, &si) ;
//从si中取出当前位置
iVertPos = si.nPos ;
//根据消息类型计算位置
switch (LOWORD (wParam))
{
case SB_TOP: //滚动到顶端
si.nPos = si.nMin ;
break ;
case SB_BOTTOM: //滚动到底部
si.nPos = si.nMax ;
break ;
case SB_LINEUP: //往上翻一行(单击滚动条的按钮)
si.nPos -= 1 ;
break ;
case SB_LINEDOWN: //往下翻一行(单击滚动条的按钮)
si.nPos += 1 ;
break ;
case SB_PAGEUP: //往上翻一页(单击滚动条的空白处)
si.nPos -= si.nPage ;
break ;
case SB_PAGEDOWN: //往下翻一页(单击滚动条的空白处)
si.nPos += si.nPage ;
break ;
case SB_THUMBTRACK: //直接拖动滚动方块(并未释放)
si.nPos = si.nTrackPos ;
break ;
default:
break ;
}
//设置pos信息，并取出设置之后的si信息
si.fMask = SIF_POS ;
SetScrollInfo (hwnd, SB_VERT, &si, TRUE) ;
GetScrollInfo (hwnd, SB_VERT, &si) ;
//如果滚动条的位置发生了变化
if (si.nPos != iVertPos)
{
//滚动窗口绘图区域
ScrollWindow (hwnd, 0, cyChar * (iVertPos - si.nPos), NULL, NULL) ;
UpdateWindow (hwnd) ;
}
return 0 ;
case WM_HSCROLL: //与纵向滚动条处理类似
// Get all the vertial scroll bar information
si.cbSize = sizeof (si) ;
si.fMask = SIF_ALL ;
// Save the position for comparison later on
GetScrollInfo (hwnd, SB_HORZ, &si) ;
iHorzPos = si.nPos ;
switch (LOWORD (wParam))
{
case SB_LINELEFT:
si.nPos -= 1 ;
break ;
case SB_LINERIGHT:
si.nPos += 1 ;
break ;
case SB_PAGELEFT:
si.nPos -= si.nPage ;
break ;
case SB_PAGERIGHT:
si.nPos += si.nPage ;
break ;
case SB_THUMBPOSITION:
si.nPos = si.nTrackPos ;
break ;
default :
break ;
}
// Set the position and then retrieve it. Due to adjustments
// by Windows it may not be the same as the value set.
si.fMask = SIF_POS ;
SetScrollInfo (hwnd, SB_HORZ, &si, TRUE) ;
GetScrollInfo (hwnd, SB_HORZ, &si) ;
// If the position has changed, scroll the window
if (si.nPos != iHorzPos)
{
ScrollWindow (hwnd, cxChar * (iHorzPos - si.nPos), 0, NULL, NULL) ;
}
return 0 ;
case WM_KEYDOWN: //处理按键消息
switch (wParam)
{
case VK_HOME: //处理home键：纵向拉到最顶部
SendMessage (hwnd, WM_VSCROLL, SB_TOP, 0) ;
break ;
case VK_END: //处理end键：纵向拉到最底部
SendMessage (hwnd, WM_VSCROLL, SB_BOTTOM, 0) ;
break ;
case VK_PRIOR: //处理pageup：纵向往上翻页
SendMessage (hwnd, WM_VSCROLL, SB_PAGEUP, 0) ;
break ;
case VK_NEXT: //处理pagedown：纵向往下翻页
SendMessage (hwnd, WM_VSCROLL, SB_PAGEDOWN, 0) ;
break ;
case VK_UP: //处理向上按键：纵向向上移动一行
SendMessage (hwnd, WM_VSCROLL, SB_LINEUP, 0) ;
break ;
case VK_DOWN: //处理向下按键：纵向向下移动一行
SendMessage (hwnd, WM_VSCROLL, SB_LINEDOWN, 0) ;
break ;
case VK_LEFT: //处理向左按键：横向up移动一页
SendMessage (hwnd, WM_HSCROLL, SB_PAGEUP, 0) ;
break ;
case VK_RIGHT: //处理向右按键：横向down移动一页
SendMessage (hwnd, WM_HSCROLL, SB_PAGEDOWN, 0) ;
break ;
}
return 0 ;
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps) ;
//获取纵向滚动条的位置
si.cbSize = sizeof (si) ;
si.fMask = SIF_POS ;
GetScrollInfo (hwnd, SB_VERT, &si) ;
iVertPos = si.nPos ;
//获取横向滚动条的位置
GetScrollInfo (hwnd, SB_HORZ, &si) ;
iHorzPos = si.nPos ;
//找到需要能在客户区显示的item
iPaintBeg = max (0, iVertPos + ps.rcPaint.top / cyChar) ;
iPaintEnd = min (NUMLINES - 1, iVertPos + ps.rcPaint.bottom / cyChar) ;
//只画需要显示的item
for (i = iPaintBeg ; i <= iPaintEnd ; i++)
{
x = cxChar * (1 - iHorzPos) ;
y = cyChar * (i - iVertPos) ;
TextOut (hdc, x, y, sysmetrics[i].szLabel, lstrlen (sysmetrics[i].szLabel)) ;
TextOut (hdc, x + 22 * cxCaps, y, sysmetrics[i].szDesc, lstrlen (sysmetrics[i].szDesc)) ;
SetTextAlign (hdc, TA_RIGHT | TA_TOP) ;
TextOut (hdc, x + 22 * cxCaps + 40 * cxChar, y, szBuffer, wsprintf (szBuffer, TEXT ("%5d"), GetSystemMetrics (sysmetrics[i].iIndex))) ;
SetTextAlign (hdc, TA_LEFT | TA_TOP) ;
}
EndPaint (hwnd, &ps) ;
return 0 ;
case WM_DESTROY :
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
/*--------------------------------------
TYPER.C -- Typing Program
(c) Charles Petzold, 1998
--------------------------------------*/
#include <windows.h>
#define BUFFER(x,y) *(pBuffer + y * cxBuffer + x)
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
//建立窗口框架
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Typer") ;
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 = szAppName ;
if (!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT ("This program requires Windows NT!"),
szAppName, MB_ICONERROR) ;
return 0 ;
}
hwnd = CreateWindow (szAppName, TEXT ("Typing Program"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static DWORD dwCharSet = DEFAULT_CHARSET ;
static int cxChar, cyChar, cxClient, cyClient, cxBuffer, cyBuffer,
xCaret, yCaret ;
static TCHAR * pBuffer = NULL ;
HDC hdc ;
int x, y, i ;
PAINTSTRUCT ps ;
TEXTMETRIC tm ;
switch (message)
{
case WM_INPUTLANGCHANGE: //输入法发生变化，修改字符集
dwCharSet = wParam ;
// fall through
case WM_CREATE: //窗体创建
hdc = GetDC (hwnd) ;
//创建缺省字体，并设置为默认字体
SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ;
//获取字体大小
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ;
cyChar = tm.tmHeight ;
//删除刚创建的缺省字体，并选入系统字体
DeleteObject (SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
ReleaseDC (hwnd, hdc) ;
// fall through
case WM_SIZE:
//窗体大小重设
if (message == WM_SIZE)
{
cxClient = LOWORD (lParam) ;
cyClient = HIWORD (lParam) ;
}
//计算需要多大的内存来容纳字符串
cxBuffer = max (1, cxClient / cxChar) ;
cyBuffer = max (1, cyClient / cyChar) ;
//释放之前的内存
if (pBuffer != NULL)
free (pBuffer) ;
//重新申请一块内存
pBuffer = (TCHAR *) malloc (cxBuffer * cyBuffer * sizeof (TCHAR)) ;
//并置为空字符串
for (y = 0 ; y < cyBuffer ; y++)
for (x = 0 ; x < cxBuffer ; x++)
BUFFER(x,y) = ' ' ;
//设置插入符号的位置为0，0
xCaret = 0 ;
yCaret = 0 ;
//若为焦点窗口则重新设置插入符号位置
if (hwnd == GetFocus ())
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
InvalidateRect (hwnd, NULL, TRUE) ;
return 0 ;
case WM_SETFOCUS:
// 获得焦点时创建并设置输入光标位置
CreateCaret (hwnd, NULL, cxChar, cyChar) ;
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
ShowCaret (hwnd) ;
return 0 ;
case WM_KILLFOCUS:
// 失去焦点时隐藏并销毁插入符号
HideCaret (hwnd) ;
DestroyCaret () ;
return 0 ;
case WM_KEYDOWN: //通过按键消息控制插入符位置，VK_DELETE删除字符
switch (wParam)
{
case VK_HOME:
xCaret = 0 ;
break ;
case VK_END:
xCaret = cxBuffer - 1 ;
break ;
case VK_PRIOR:
yCaret = 0 ;
break ;
case VK_NEXT:
yCaret = cyBuffer - 1 ;
break ;
case VK_LEFT:
xCaret = max (xCaret - 1, 0) ;
break ;
case VK_RIGHT:
xCaret = min (xCaret + 1, cxBuffer - 1) ;
break ;
case VK_UP:
yCaret = max (yCaret - 1, 0) ;
break ;
case VK_DOWN:
yCaret = min (yCaret + 1, cyBuffer - 1) ;
break ;
case VK_DELETE: //删除字符
//当前行所有在被删除字符之后的字符都向前移动一位
for (x = xCaret ; x < cxBuffer - 1 ; x++)
BUFFER (x, yCaret) = BUFFER (x + 1, yCaret) ;
//最后一位设置为空
BUFFER (cxBuffer - 1, yCaret) = ' ' ;
//隐藏光标
HideCaret (hwnd) ;
//获取DC
hdc = GetDC (hwnd) ;
//设置缺省字体
SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ;
//输出文字
TextOut (hdc, xCaret * cxChar, yCaret * cyChar,
& BUFFER (xCaret, yCaret),
cxBuffer - xCaret) ;
//删除创建的缺省字体并选中默认字体
DeleteObject (SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
ReleaseDC (hwnd, hdc) ;
//重新显示光标
ShowCaret (hwnd) ;
break ;
}
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
return 0 ;
case WM_CHAR: //处理字符消息
for (i = 0 ; i < (int) LOWORD (lParam) ; i++)
{
switch (wParam)
{
case '\b': // backspace
if (xCaret > 0)
{
xCaret-- ;
SendMessage (hwnd, WM_KEYDOWN, VK_DELETE, 1) ;
}
break ;
case '\t': // tab
do
{
SendMessage (hwnd, WM_CHAR, ' ', 1) ;
}
while (xCaret % 8 != 0) ;
break ;
case '\n': // line feed
if (++yCaret == cyBuffer)
yCaret = 0 ;
break ;
case '\r': // carriage return
xCaret = 0 ;
if (++yCaret == cyBuffer)
yCaret = 0 ;
break ;
case '\x1B': // escape
for (y = 0 ; y < cyBuffer ; y++)
for (x = 0 ; x < cxBuffer ; x++)
BUFFER (x, y) = ' ' ;
xCaret = 0 ;
yCaret = 0 ;
InvalidateRect (hwnd, NULL, FALSE) ;
break ;
default: // character codes
//在当前字符插入符号所在位置插入字符并显示，过程与VK_DELETE相似
BUFFER (xCaret, yCaret) = (TCHAR) wParam ;
HideCaret (hwnd) ;
hdc = GetDC (hwnd) ;
SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ;
TextOut (hdc, xCaret * cxChar, yCaret * cyChar,
& BUFFER (xCaret, yCaret), 1) ;
DeleteObject (
SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
ReleaseDC (hwnd, hdc) ;
ShowCaret (hwnd) ;
if (++xCaret == cxBuffer)
{
xCaret = 0 ;
if (++yCaret == cyBuffer)
yCaret = 0 ;
}
break ;
}
}
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
return 0 ;
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps) ;
//选中字体
SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ;
//画出所有字符串
for (y = 0 ; y < cyBuffer ; y++)
TextOut (hdc, 0, y * cyChar, & BUFFER(0,y), cxBuffer) ;
//删除，并设置为默认字体
DeleteObject (SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
EndPaint (hwnd, &ps) ;
return 0 ;
case WM_DESTROY:
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
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