第五章 绘图基础（SINEWAVE）

 1 //SINEWAVE.C -- Sine Wave Using Polyline (c) Charles Petzold, 1998
 2 #include <Windows.h>
 3 #include <math.h>
 4 
 5 #define NUM        1000
 6 #define TWOPI    (2 * 3.14159)
 7 
 8 LRESULT CALLBACK WndPorc(HWND, UINT, WPARAM, LPARAM);
 9 
10 int WINAPI WinMain( __in HINSTANCE hInstance
11                     , __in_opt HINSTANCE hPrevInstance
12                     , __in LPSTR lpCmdLine
13                     , __in int nShowCmd )
14 {
15     static TCHAR szAppName[] = TEXT("SineWave");
16     HWND hwnd;
17     MSG msg;
18     WNDCLASS wndclass;
19 
20     wndclass.style = CS_HREDRAW | CS_VREDRAW;
21     wndclass.lpfnWndProc = WndPorc;
22     wndclass.cbClsExtra = 0;
23     wndclass.cbWndExtra = 0;
24     wndclass.hInstance = hInstance;
25     wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
26     wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
27     wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
28     wndclass.lpszMenuName = NULL;
29     wndclass.lpszClassName = szAppName;
30 
31     if (!RegisterClass(&wndclass))
32     {
33         MessageBox(NULL, TEXT("Program requires Windows NT!")
34             , szAppName, MB_ICONERROR);
35         return 0;
36     }
37 
38     hwnd = CreateWindow(szAppName, TEXT("Sine Wave Using Polyline")
39         , WS_OVERLAPPEDWINDOW
40         , CW_USEDEFAULT, CW_USEDEFAULT
41         , CW_USEDEFAULT, CW_USEDEFAULT
42         , NULL, NULL, hInstance, NULL);
43 
44     ShowWindow(hwnd, nShowCmd);
45     UpdateWindow(hwnd);
46 
47     while (GetMessage(&msg, NULL, 0, 0))
48     {
49         TranslateMessage(&msg);
50         DispatchMessage(&msg);
51     }
52 
53     return msg.wParam;
54 }
55 
56 LRESULT CALLBACK WndPorc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
57 {
58     static int cxClient, cyClient;
59     HDC hdc;
60     int i;
61     PAINTSTRUCT ps;
62     POINT apt[NUM];
63 
64     switch (message)
65     {
66     case WM_SIZE:
67         cxClient = LOWORD(lParam);
68         cyClient = HIWORD(lParam);
69         return 0;
70 
71     case WM_PAINT:
72         hdc = BeginPaint(hwnd, &ps);
73         
74         MoveToEx(hdc, 0, cyClient / 2, NULL);
75         LineTo(hdc, cxClient, cyClient / 2);
76         
77         for (i = 0; i != NUM; ++i)
78         {
79             apt[i].x = i * cxClient / NUM;
80             apt[i].y = (int)(cyClient / 2 * (1 - sin(TWOPI * i / NUM)));
81         }
82 
83         Polyline(hdc, apt, NUM);
84         EndPaint(hwnd, &ps);
85         return 0;
86 
87     case WM_DESTROY:
88         PostQuitMessage(0);
89         return 0;
90     }
91 
92     return DefWindowProc(hwnd, message, wParam, lParam);
93 }