#include
#define NUMLINES ((int) (sizeof devcaps / sizeof devcaps [0]))
struct
{
int iIndex ;
TCHAR * szLabel ;
TCHAR * szDesc ;
}
devcaps [] =
{
HORZSIZE, TEXT ("HORZSIZE"), TEXT ("Width in millimeters:"),
VERTSIZE, TEXT ("VERTSIZE"), TEXT ("Height in millimeters:"),
HORZRES, TEXT ("HORZRES"), TEXT ("Width in pixels:"),
VERTRES, TEXT ("VERTRES"), TEXT ("Height in raster lines:"),
BITSPIXEL, TEXT ("BITSPIXEL"), TEXT ("Color bits per pixel:"),
PLANES, TEXT ("PLANES"), TEXT ("Number of color planes:"),
NUMBRUSHES, TEXT ("NUMBRUSHES"), TEXT ("Number of device brushes:"),
NUMPENS, TEXT ("NUMPENS"), TEXT ("Number of device pens:"),
NUMMARKERS, TEXT ("NUMMARKERS"), TEXT ("Number of device markers:"),
NUMFONTS, TEXT ("NUMFONTS"), TEXT ("Number of device fonts:"),
NUMCOLORS, TEXT ("NUMCOLORS"), TEXT ("Number of device colors:"),
PDEVICESIZE, TEXT ("PDEVICESIZE"), TEXT ("Size of device structure:"),
ASPECTX, TEXT ("ASPECTX"), TEXT ("Relative width of pixel:"),
ASPECTY, TEXT ("ASPECTY"), TEXT ("Relative height of pixel:"),
ASPECTXY, TEXT ("ASPECTXY"), TEXT ("Relative diagonal of pixel:"),
LOGPIXELSX, TEXT ("LOGPIXELSX"), TEXT ("Horizontal dots per inch:"),
LOGPIXELSY, TEXT ("LOGPIXELSY"), TEXT ("Vertical dots per inch:"),
SIZEPALETTE, TEXT ("SIZEPALETTE"), TEXT ("Number of palette entries:"),
NUMRESERVED, TEXT ("NUMRESERVED"), TEXT ("Reserved palette entries:"),
COLORRES, TEXT ("COLORRES"), TEXT ("Actual color resolution:")
} ;
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("DevCaps1") ;
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 ("Device Capabilities"),
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,cxClient,cyClient,xy,yy;
TCHAR szBuffer[10] ;
HDC hdc ;
int i ;
PAINTSTRUCT ps ;
TEXTMETRIC tm ;
switch (message)
{
case WM_CREATE:
hdc = GetDC (hwnd) ;
xy=1000;
yy=1000;
SetMapMode(hdc,MM_ISOTROPIC);
SetWindowExtEx(hdc,xy,yy,NULL);
SetViewportExtEx(hdc,cxClient,-cyClient,NULL);
SetViewportOrgEx(hdc,0,cyClient,NULL);
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ;
cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2) * cxChar / 2 ;
cyChar = tm.tmHeight + tm.tmExternalLeading ;
ReleaseDC (hwnd, hdc) ;
return 0 ;
case WM_SIZE:
cxClient=LOWORD(lParam);
cyClient=HIWORD(lParam);
return 0;
case WM_KEYDOWN:
switch(wParam)
{
case VK_LEFT:
xy=xy/2;
yy=yy/2;
SetWindowExtEx(hdc,xy,yy,NULL);
InvalidateRect(hwnd,NULL,TRUE);
break;
case VK_RIGHT:
xy=xy*2;
yy=yy*2;
SetWindowExtEx(hdc,xy,yy,NULL);
InvalidateRect(hwnd,NULL,TRUE);
break;
}
return 0;
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps) ;
for (i = 0 ; i < NUMLINES ; i++)
{
TextOut (hdc, 0, cyChar * i,
devcaps[i].szLabel,
lstrlen (devcaps[i].szLabel)) ;
TextOut (hdc, 14 * cxCaps, cyChar * i,
devcaps[i].szDesc,
lstrlen (devcaps[i].szDesc)) ;
SetTextAlign (hdc, TA_RIGHT | TA_TOP) ;
TextOut (hdc, 14 * cxCaps + 35 * cxChar, cyChar * i, szBuffer,
wsprintf (szBuffer, TEXT ("%5d"),
GetDeviceCaps (hdc, devcaps[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) ;
}
代码如上,是以windows程序设计第五章的devcaps1程序为例子的,只是在WM_CREATE里加了点,然后加了个wm_keydown,我想实现的效果是:每次按下左箭头,实际上视口逻辑单位缩小一半,那么在上面显示的文字应该放大一倍,但实际上没有变化,我想实现的效果类似于CAD画图时,滚动中键实现图片文字放大缩小的那种效果,请问应该如何才能实现,请知道的告诉下,谢谢了