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 = 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 ("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, 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 ; HDC hdc ; int i ; PAINTSTRUCT ps ; TCHAR szBuffer [10] ; 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 & 1 ? 3 : 2) * cxChar / 2 ; // 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 0 ; case WM_PAINT : hdc = BeginPaint (hwnd, &ps) ; for (i = 0 ; i < NUMLINES ; i++) { TextOut (hdc, 0, cyChar * i, sysmetrics[i].szLabel, lstrlen (sysmetrics[i].szLabel)) ; TextOut (hdc, 22 * cxCaps, cyChar * i, sysmetrics[i].szDesc, lstrlen (sysmetrics[i].szDesc)) ; SetTextAlign (hdc, TA_RIGHT | TA_TOP) ; TextOut (hdc, 22 * cxCaps + 40 * cxChar, cyChar * i, 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) ; }
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