头文件：

#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 draggable width"),
SM_CYMAXTRACK, TEXT ("SM_CYMAXTRACK"),
TEXT ("Maximum draggable 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")

} ;

源代码：

#define WINVER 0x0500
#include
#include "sysmets.h"
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("SysMets1") ;
HWND hwnd ;
MSG msg ;
WNDCLASS wndclass ;
wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = ;
wndclass.cbWndExtra = ;
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 ;
}
hwnd = CreateWindow (szAppName, TEXT ("Get System Metrics No. 1"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, , ))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static int cxChar, cxCaps, cyChar ;
HDC hdc ;
int i ;
PAINTSTRUCT ps ;
TCHAR szBuffer [] ;
TEXTMETRIC tm ;
switch (message)
{
case WM_CREATE:
hdc = GetDC (hwnd) ;
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ;
cxCaps = (tm.tmPitchAndFamily & ? : ) * cxChar / ;
cyChar = tm.tmHeight + tm.tmExternalLeading ;
ReleaseDC (hwnd, hdc) ;
return ;
case WM_PAINT :
hdc = BeginPaint (hwnd, &ps) ;
for (i = ; i < NUMLINES ; i++)
{
TextOut (hdc, , cyChar * i,
sysmetrics[i].szLabel,
lstrlen (sysmetrics[i].szLabel)) ;
TextOut (hdc, * cxCaps, cyChar * i,
sysmetrics[i].szDesc,
lstrlen (sysmetrics[i].szDesc)) ;
SetTextAlign (hdc, TA_RIGHT | TA_TOP) ;
TextOut (hdc, * cxCaps + * cxChar, cyChar * i, szBuffer,
wsprintf (szBuffer, TEXT ("%5d"),
GetSystemMetrics (sysmetrics[i].iIndex))) ;
SetTextAlign (hdc, TA_LEFT | TA_TOP) ;
}
EndPaint (hwnd, &ps) ;
return ;
case WM_DESTROY :
PostQuitMessage () ;
return ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}

关于#define WINVER 0x0500 这句话必须放在程序最开始.

因为VC6.0 的默认编译环境为WINVER=0x0400,也就是在Windows95，或WindowsNT4.0以及以上运行的 。

WINVER>=0X0500 指Win2000以上。有些API 或常数只有在Win2000以上才支持。

WINVER 定义了决定构建应用程序所需的最低平台SDK,而这又将在编译时确定哪些例程是由头文件找到的。

cxChar变量表示平均字符宽度，字符的总高度(包括外部间距)保存在 cyChar变量中，将大写字符的平均宽度保存在cxCaps中。

前缀c代表"count"，也就是"个数"。在这里代表像素数。它们被定义为静态变量，是因为它们必须在Windows处理其他消息时还有效。

变量 i 表示字符行数。

TEXTMETRIC 结构体用来保存字符尺寸的值。程序通过调用 GetSystemMetrics() 函数来获取用户界面尺寸，

同样的，通过调用GetTextMetrics() 函数，程序可以获取字体尺寸。

GetTextMetrics() 函数需要一个设备环境句柄，因为它会返回该设备环境中当前选定的字体的信息，

并将这些值复制到类型为 TEXTMETRIC的结构体中，该结构体有20个字段，但我们现在仅关心其中前7个。

typedef struct tagTEXTMETRIC {

LONG tmHeight; //字符高度

LONG tmAscent; //字符上部高度(基线以上)

LONG tmDescent; //字符下部高度(基线以下)

LONG tmInternalLeading, //由tmHeight定义的字符高度的顶部空间数目

LONG tmExternalLeading, //夹在两行之间的空间数目

LONG tmAveCharWidth, //平均字符宽度

LONG tmMaxCharWidth, //最宽字符的宽度

LONG tmWeight; //字体的粗细轻重程度

LONG tmOverhang, //加入某些拼接字体上的附加高度

LONG tmDigitizedAspectX, //字体设计所针对的设备水平方向

LONG tmDigitizedAspectY, //字体设计所针对的设备垂直方向

BCHAR tmFirstChar; //为字体定义的第一个字符

BCHAR tmLastChar; //为字体定义的最后一个字符

BCHAR tmDefaultChar; //字体中所没有字符的替代字符

BCHAR tmBreakChar; //用于拆字的字符

BYTE tmItalic, //字体为斜体时非零

BYTE tmUnderlined, //字体为下划线时非零

BYTE tmStruckOut, //字体被删去时非零

BYTE tmPitchAndFamily, //字体间距(低4位)和族(高4位)

BYTE tmCharSet; //字体的字符集

} TEXTMETRIC;

这些字段的值的单位取决于设备环境中当前选定的映射模式。默认的映射模式是MM_TEXT,所以它们的值是以像素为单位的。

在调用GetTextMetrics() 函数前，首先要定义一个结构变量，通常命名为 tm；

需要获取字号时，首先获取设备环境句柄，然后调用GetTextMetrics；

在等宽字体中，cxCaps设为cxChar的1.5倍。在TEXTMETRIC结构中，tmPitchAndFamily字段的低位决定字体

是否为等宽字体：1 代表变量字体，0 代表等宽字体。

在早期的Windows中，系统字体是一种等宽字体：所有字符的宽度是一样的。

但从 Windows 3.0开始，系统字体变成了变宽字体：每一个字符的宽度是不一样的。

例如字符"w"就比字符"i"要宽。很明显变宽字体比等宽字体可读性强。

系统字体是一种“点阵字体”：每个字符由像素点构成。在某种程度上，系统字体中字符的大小取决于显示器的大小：

系统字体的设计要求能够在显示器上起码显示25行80列字符。

值得重视的是，系统字体的尺寸取决于Windows运行时的显示分辨率，有时还取决于用户选定的系统字号。

注意了：头文件的结构体的大括号后面没有分号，所以头文件的意思就是：

sysmetrics[0].iIndex 也就是 SM_CXSCREEN ;

sysmetrics[0].szlabel 也就是 "SM_CXSCREEN" ;

sysmetrics[0].szDesc 也就是 "screen width in pixels" ;

……

……

……

至于第二个TextOut 里的 22*cxCaps 意思是在第一栏的字符最长的有20个字符，多出来的2个是为了留出两栏间的空隙。

使用 SetTextAlign() 函数的目的仅是为了让右边对齐。