win32画正弦曲线

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#include <windows.h>#include <math.h>// - 数学函数#include  <sstream>// - C++格式化字符串需要using namespace std;LRESULT CALLBACK MywndProc(HWND hwnd,UINT uMsg,WPARAM wParam,LPARAM lParam);int WINAPI WinMain(HINSTANCE hInstacne,HINSTANCE hPreview,PSTR CmdLine,int CmdShow){WNDCLASS wndcls;wndcls.cbClsExtra = 0;wndcls.cbWndExtra = 0;wndcls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);wndcls.hCursor = LoadCursor(NULL,IDC_ARROW);wndcls.hIcon = LoadIcon(NULL,IDI_APPLICATION);wndcls.hInstance = hInstacne;wndcls.lpfnWndProc = MywndProc;    wndcls.lpszClassName = TEXT("bear");wndcls.lpszMenuName = NULL;wndcls.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;if(!RegisterClass(&wndcls)){MessageBox(NULL,TEXT("此程序需要Windows NT系统的支持!"),TEXT("小熊提示"),MB_ICONERROR);return 0;}HWND hwnd = CreateWindow(TEXT("bear"),TEXT("小熊"), WS_SYSMENU | WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SIZEBOX,100,100,500,600,NULL,NULL,hInstacne,NULL);    ShowWindow(hwnd,CmdShow);UpdateWindow(hwnd);MSG msg;while(GetMessage(&msg,NULL,0,0)){TranslateMessage(&msg);DispatchMessage(&msg);}return msg.wParam;}LRESULT CALLBACK MywndProc(HWND hwnd,UINT uMsg,WPARAM wParam,LPARAM lParam){HDC hdc;static int cxClient,cyClient;double y = 0;PAINTSTRUCT ps;double pa=3.1415;    switch(uMsg){case WM_SIZE:// - 窗口大小改变时的消息cxClient = LOWORD(lParam);// - 存储窗口的宽度cyClient = HIWORD(lParam);// - 存储窗口的高度return 0;case WM_PAINT:// - 窗口绘画消息hdc = BeginPaint(hwnd,&ps);// - 获取绘画DCSetViewportOrgEx(hdc,cxClient/2,cyClient/2,NULL);// - 将坐标点设置到窗口的中央SetMapMode(hdc,MM_LOENGLISH);//设置映射模式，让坐标正负方向与数学的xy轴一致TextOut(hdc,-150,170,"C++技术网 VIP会员解答",strlen("C++技术网 VIP会员解答"));TextOut(hdc,-150,150,"算法代码程序效果图",strlen("算法代码程序效果图"));// - 画坐标// - 从左到右MoveToEx(hdc,-cxClient/2,0,NULL);LineTo(hdc,cxClient/2,0);// - 从下到上MoveToEx(hdc,0,-cyClient/2,NULL);LineTo(hdc,0,cyClient/2);// - 水平刻度线for (float i=-cxClient;i<=cxClient;i+=3.14/4){// - C++格式化字符串ostringstream ostr;ostr << i/100;string str = ostr.str();// - 隔一定距离画水平刻度线if((int)i%50==0){// - 画水平刻度线MoveToEx(hdc,i,0,NULL);LineTo(hdc,i,5);}}// - 垂直刻度线和刻度值for (float i=-cyClient;i<=cyClient;i++){ostringstream ostr;ostr << i/100;string str = ostr.str();if((int)i%50==0){TextOut(hdc,5,i,str.c_str(),str.length());MoveToEx(hdc,0,i,NULL);LineTo(hdc,5,i);}}EndPaint(hwnd,&ps);return 0;    case WM_LBUTTONDOWN:hdc = GetDC(hwnd);// - 获取窗口绘制的DC// - 因为这个DC和WM_PAINT消息的DC不是同一个DC，所以还要设置原点坐标和坐标轴方向SetViewportOrgEx(hdc,cxClient/2,cyClient/2,NULL);//设置坐标原点SetMapMode(hdc,MM_LOENGLISH);//设置映射模式，让坐标正负方向与数学的xy轴一致MoveToEx(hdc,-cxClient/2,0,NULL);// - 移动原点到x轴最左边TextOut(hdc,-150,130,"三角函数sin曲线图",strlen("三角函数sin曲线图"));// - 输出函数说明信息// - 计算坐标值和绘图for (double x=-cxClient/2;x<=cxClient/2;x+=0.01){// - 通过公式来计算x,y的值，形成坐标点//y = x*x*x;//y = tan(x);y = sin(x);//y = x;//y = cos(x);// - 划线，因为间隔很小，所以看上去曲线比较光滑LineTo(hdc,x*15,y*100);// - 放大坐标的倍数，是让曲线扩展下，让曲线看起来更舒服}ReleaseDC(hwnd,hdc);return 0;case WM_DESTROY:PostQuitMessage(0);return 0;}return DefWindowProc(hwnd,uMsg,wParam,lParam);}
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