本程序使用GetSystemMetrics获取windows各种图像选项，并输出字符到窗口中。
#define WINVER 0x0500
#include <windows.h>
#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 ; // 平均字符宽度
cxCaps = (tm.tmPitchAndFamily & ? : ) * cxChar / ; // 字体间距(低4位)和族(高4位)
cyChar = tm.tmHeight + tm.tmExternalLeading ; // 字符高度 + 夹在两行之间的空间数目 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) ;
}
在创建窗口时使用GetTextMetrics函数获取用户界面尺寸，获取设备上下文，包括字符宽度、高度等。
关于TEXTMETRIC结构体，定义如下：
typedef struct tagTEXTMETRIC {
LONG tmHeight;
LONG tmAscent;
LONG tmDescent;
LONG tmInternalLeading;
LONG tmExternalLeading;
LONG tmAveCharWidth;
LONG tmMaxCharWidth;
LONG tmWeight;
LONG tmOverhang;
LONG tmDigitizedAspectX;
LONG tmDigitizedAspectY;
TCHAR tmFirstChar;
TCHAR tmLastChar;
TCHAR tmDefaultChar;
TCHAR tmBreakChar;
BYTE tmItalic;
BYTE tmUnderlined;
BYTE tmStruckOut;
BYTE tmPitchAndFamily;
BYTE tmCharSet;
} TEXTMETRIC, *PTEXTMETRIC;
在绘图时，使用GetSystemMetrics获取系统图形信息，再调用TextOut函数输出文本至窗口。
int WINAPI GetSystemMetrics(
__in int nIndex
);
这里我们在头文件定义了sysmetrics数组，把需要得到的系统数据或者系统配置信息名称写好。
/*-----------------------------------------------
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 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")
} ;
整个程序结构与上一篇的几乎一致。
不过这个程序还是有很多不足，比如坐标通过直接定义，未考虑窗口尺寸大小，输出信息可能不能完全显示等，后面我们再通过修改程序进一步完善