关于响应键盘的一个程序

[ncufunk]

#include <windows.h>
#include <stdlib.h>

#define BUFFER(x,y) *(pBuffer + y * cxBuffer + x)

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static char szAppName[] = "Typer" ;
HWND hwnd ;
MSG msg ;
WNDCLASSEX wndclass ;

wndclass.cbSize = sizeof (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 ;
wndclass.hIconSm = LoadIcon (NULL, IDI_APPLICATION) ;

RegisterClassEx (&wndclass) ;

hwnd = CreateWindow (szAppName, "键盘输入示例",
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 iMsg, WPARAM wParam, LPARAM lParam)
{
static char *pBuffer = NULL ;
static int cxChar, cyChar, cxClient, cyClient, cxBuffer, cyBuffer,
xCaret, yCaret ;
HDC hdc ;
int x, y, i ;
PAINTSTRUCT ps ;
TEXTMETRIC tm ;

switch (iMsg)
{
case WM_CREATE :
hdc = GetDC (hwnd) ;

SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ;
cyChar = tm.tmHeight ;

ReleaseDC (hwnd, hdc) ;
return 0 ;

case WM_SIZE :
// obtain window size in pixels

cxClient = LOWORD (lParam) ;
cyClient = HIWORD (lParam) ;

// calculate window size in characters

cxBuffer = max (1, cxClient / cxChar) ;
cyBuffer = max (1, cyClient / cyChar) ;

// allocate memory for buffer and clear it

if (pBuffer != NULL)
free (pBuffer) ;

if ((pBuffer = (char *) malloc (cxBuffer * cyBuffer)) == NULL)
MessageBox (hwnd, "Window too large. Cannot "
"allocate enough memory.", "Typer",
MB_ICONEXCLAMATION | MB_OK) ;
else
for (y = 0 ; y < cyBuffer ; y++)
for (x = 0 ; x < cxBuffer ; x++)
BUFFER(x,y) = ' ' ;

// set caret to upper left corner
xCaret = 0 ;
yCaret = 0 ;

if (hwnd == GetFocus ())
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;

return 0 ;

case WM_SETFOCUS :
// create and show the caret

CreateCaret (hwnd, NULL, cxChar, cyChar) ;
SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
ShowCaret (hwnd) ;
return 0 ;

case WM_KILLFOCUS :
// hide and destroy the caret
HideCaret (hwnd) ;
DestroyCaret () ;
return 0 ;

case WM_KEYDOWN :
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 :
for (x = xCaret ; x < cxBuffer - 1 ; x++)
BUFFER (x, yCaret) = BUFFER (x + 1, yCaret) ;

BUFFER (cxBuffer - 1, yCaret) = ' ' ;

HideCaret (hwnd) ;
hdc = GetDC (hwnd) ;

SelectObject (hdc,
GetStockObject (SYSTEM_FIXED_FONT)) ;

TextOut (hdc, xCaret * cxChar, yCaret * cyChar,
& BUFFER (xCaret, yCaret),
cxBuffer - xCaret) ;

ShowCaret (hwnd) ;
ReleaseDC (hwnd, hdc) ;
break ;
}

SetCaretPos (xCaret * cxChar, yCaret * cyChar) ;
return 0 ;

[ncufunk]

case WM_CHAR :
for (i = 0 ; i < (int) LOWORD (lParam) ; i++)
{
switch (wParam)
{
case '\b' : // backspace
if (xCaret > 0)
{
xCaret-- ;
SendMessage (hwnd, WM_KEYDOWN,
VK_DELETE, 1L) ;
}
break ;

case '\t' : // tab
do
{
SendMessage (hwnd, WM_CHAR, ' ', 1L) ;
}
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
BUFFER (xCaret, yCaret) = (char) wParam ;

HideCaret (hwnd) ;
hdc = GetDC (hwnd) ;

SelectObject (hdc,
GetStockObject (SYSTEM_FIXED_FONT)) ;

TextOut (hdc, xCaret * cxChar, yCaret * cyChar,
& BUFFER (xCaret, yCaret), 1) ;

ShowCaret (hwnd) ;
ReleaseDC (hwnd, hdc) ;

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) ;
SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;

for (y = 0 ; y < cyBuffer ; y++)
TextOut (hdc, 0, y * cyChar, & BUFFER(0,y), cxBuffer) ;

EndPaint (hwnd, &ps) ;
return 0 ;

case WM_DESTROY :
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
}
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其中xCaret, yCaret ;是什么意思？
还有：case WM_CHAR : 是用来干什么的 ？

[feeboby]

xCaret表示光标处横向字符数
yCaret表示光标处纵向字符数
case WM_CHAR ：处理键盘击键值的消息