windows程序设计读书笔记2——字符显示1

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