KGLab5_3

#include <windows.h>
#include <tchar.h>
#include <math.h>
#include <fstream>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
TCHAR WinName[] = _T("MainFrame");

static int sx,sy;
const int SCALE = 1000;
const int MARK = 4;
int n,i,j,first;
float x,y,X,Y,t,xA,xB,xC,xD,yA,yB,yC,yD,a0,a1,a2,a3,b0,b1,b2,b3,eps=0.04;

void DcInLp (POINT &point)
{
    point.x = point.x*SCALE/sx;
    point.y = SCALE - point.y * SCALE/sy;
}

void transform(HDC &hdc)
{
    SetMapMode (hdc, MM_ANISOTROPIC);
    SetWindowExtEx(hdc,SCALE,-SCALE,NULL);
    SetViewportExtEx(hdc,sx,sy,NULL);
    SetViewportOrgEx(hdc,0,sy,NULL);
}


int APIENTRY WinMain(HINSTANCE This, HINSTANCE Prev, LPSTR cmd, int mode)
{
    HWND hWnd;
    MSG msg;
    WNDCLASS wc;
    wc.hInstance = This;
    wc.lpszClassName = WinName;
    wc.lpfnWndProc = WndProc;
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.lpszMenuName = NULL;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    if(!RegisterClass(&wc)) return 0;
    hWnd = CreateWindow(WinName, _T("B-spline"),
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        HWND_DESKTOP,
        NULL,
        This,
        NULL);

    ShowWindow(hWnd, mode);
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0; }
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    static HBRUSH hRect,hSel;
    static HPEN hDash, hBezier;
    static POINT pt[20];
    static POINT point;
    RECT rt;
    static int count, index;
    static bool capture;
    int i;
    std::ifstream in;
    std::ofstream out;
    switch(message){
    case WM_CREATE:
        in.open("dat.txt");
        if (in.fail())
        {
            MessageBox (hWnd,_T("Файл не найден"),_T("Открытие файла"),MB_OK|MB_ICONEXCLAMATION);
            PostQuitMessage(0);
            return 1; }
        for (count = 0; in >> pt [count].x; count++) in >> pt[count].y;
        in.close();
        hDash = CreatePen (PS_DASH,1,0);
        hBezier = CreatePen (PS_SOLID, 4, RGB(255,0,0));
        hRect = CreateSolidBrush (RGB(128,0,128));
        hSel = CreateSolidBrush (RGB(255,0,0));
        break;
    case WM_SIZE:
        sx = LOWORD(lParam);
        sy = HIWORD(lParam);
        break;
    case WM_LBUTTONDOWN:
        point.x = LOWORD(lParam);
        point.y = HIWORD(lParam);
        DcInLp(point);
        for (i = 0; i <= count; i++)
        {
            SetRect(&rt, pt[i].x-MARK, pt[i].y-MARK, pt[i].x+MARK,pt[i].y+MARK);
            if(PtInRect(&rt, point))
            {
                index = i;
                capture = true;
                hdc = GetDC(hWnd);
                transform(hdc);
                FillRect(hdc, &rt, hSel);
                ReleaseDC(hWnd, hdc);
                SetCapture(hWnd);
                return 0; } }
        break;
    case WM_LBUTTONUP:
        if(capture)
        {
            ReleaseCapture();
            capture = false;
        }
        break;
    case WM_MOUSEMOVE:
        if (capture)
        {
            point.x = LOWORD (lParam);
            point.y = HIWORD (lParam);
            DcInLp (point);
            pt[index] = point;
            InvalidateRect (hWnd,NULL,TRUE);
        }
        break;
    case WM_PAINT:
        hdc = BeginPaint (hWnd,&ps);
        transform (hdc);
        SelectObject (hdc, hDash);
        Polyline (hdc, pt, count);
        SelectObject (hdc, hBezier);
        point.x = LOWORD(lParam);
        point.y = HIWORD(lParam);
        DcInLp(point);
        for (i = 0; i <= count; i++)
        {
            MoveToEx(hdc, pt[i].x-eps, pt[i].y-eps, NULL);
            LineTo(hdc, pt[i].x+eps,pt[i].y+eps);
            MoveToEx(hdc, pt[i].x+eps, pt[i].y-eps, NULL);
            LineTo(hdc, pt[i].x-eps,pt[i].y+eps);
        }
        first = 1;
        for (i=1;i<count-1;i++)
        { xA=pt[i-1].x;xB=pt[i].x;xC=pt[i+1].x;xD=pt[i+2].x;
        yA=pt[i-1].y;yB=pt[i].y;yC=pt[i+1].y;yD=pt[i+2].y;
        a3=(-xA+3*(xB-xC)+xD)/6; b3=(-yA+3*(yB-yC)+yD)/6;
        a2=(xA-2*xB+xC)/2; b2=(yA-2*yB+yC)/2;
        a1=(xC-xA)/2; b1=(yC-yA)/2;
        a0=(xA+4*xB+xC)/6; b0=(yA+4*yB+yC)/6;
        for (j=0;j<=count;j++)
        { t=(float)j/(float)count;
        X=((a3*t+a2)*t+a1)*t+a0; Y=((b3*t+b2)*t+b1)*t+b0;
        if (first)
        { first=0;
        MoveToEx(hdc,X,Y, NULL);
        }
        else LineTo(hdc,X,Y);
        } }
        EndPaint(hWnd,&ps);
        break;
    case WM_DESTROY:
        DeleteObject(hDash);
        DeleteObject(hBezier);
        DeleteObject(hRect);
        DeleteObject(hSel);
        out.open("dat.txt");
        for (i = 0; i<count; i++) out << pt[i].x << '\t'<< pt[i].y << '\n';
        out.close();
        PostQuitMessage(0);
        break;
    default: return DefWindowProc(hWnd, message, wParam, lParam);
    } return 0; }