Rasterization/Circle_Rasterization.cpp at main · MariamMedhatShawky/Rasterization · GitHub

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#include <windows.h>
#include <cmath>
#include <algorithm>
using namespace std;

void DrawLineDDA(HDC hdc, int x1, int y1, int x2, int y2, COLORREF c) {
    int dx = x2 - x1, dy = y2 - y1;
    if (abs(dx) >= abs(dy)) {
        if (x1 > x2) {
            swap(x1, x2);
            swap(y1, y2);
        }
        double m = (double)dy / dx, y = y1;

        for (int x = x1; x <= x2; x++) {
            SetPixel(hdc, x, (int)round(y), c);
            y += m;
        }
    } else {
        if (y1 > y2) { swap(x1, x2); swap(y1, y2); }
        double minv = (double)dx / dy, x = x1;

        for (int y = y1; y <= y2; y++){
            SetPixel(hdc, (int)round(x), y, c);
            x += minv;
        }
    }
}

void Draw8Points(HDC hdc, int xc, int yc, int x, int y, COLORREF c) {
    SetPixel(hdc, xc + x, yc + y, c); SetPixel(hdc, xc - x, yc + y, c);
    SetPixel(hdc, xc + x, yc - y, c); SetPixel(hdc, xc - x, yc - y, c);
    SetPixel(hdc, xc + y, yc + x, c); SetPixel(hdc, xc - y, yc + x, c);
    SetPixel(hdc, xc + y, yc - x, c); SetPixel(hdc, xc - y, yc - x, c);
}

void DrawCirclePolar(HDC hdc, int xc, int yc, int R, COLORREF c) {
    if (R <= 0) return;
    double dtheta = 1.0 / R;
    for (double th = 0; th <= 0.785398; th += dtheta)
        Draw8Points(hdc, xc, yc, (int)round(R * cos(th)), (int)round(R * sin(th)), c);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp) {
    static int xc, yc, hasC = 0;

    if (msg == WM_LBUTTONDOWN) {
        xc = LOWORD(lp); yc = HIWORD(lp); hasC = 1;
    }
    else if (msg == WM_RBUTTONDOWN && hasC) {
        int x1 = LOWORD(lp), y1 = HIWORD(lp);
        HDC hdc = GetDC(hwnd);
        int R = (int)round(sqrt(pow(x1 - xc, 2) + pow(y1 - yc, 2)));

        DrawCirclePolar(hdc, xc, yc, R, RGB(0,0,0));
        DrawLineDDA(hdc, xc - R, yc, xc + R, yc, RGB(0,0,0));
        DrawLineDDA(hdc, xc, yc - R, xc, yc + R, RGB(0,0,0));

        int f = (int)round(R * 0.7071);

        DrawLineDDA(hdc, xc - f, yc - f, xc + f, yc + f, RGB(0,0,0));
        DrawLineDDA(hdc, xc + f, yc - f, xc - f, yc + f, RGB(0,0,0));

        ReleaseDC(hwnd, hdc);
        hasC = 0;
    }
    else if (msg == WM_DESTROY) {
        PostQuitMessage(0);
    }
    return DefWindowProc(hwnd, msg, wp, lp);
}

int main() {
    HINSTANCE h = GetModuleHandle(NULL);
    WNDCLASS wc = { 0 };
    wc.lpfnWndProc = WndProc; wc.hInstance = h;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.lpszClassName = "CircleApp";
    RegisterClass(&wc);
    HWND hwnd = CreateWindow("CircleApp", "Graphics Task", WS_OVERLAPPEDWINDOW | WS_VISIBLE, 100, 100, 800, 600, NULL, NULL, h, NULL);
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg); DispatchMessage(&msg);
    }
    return 0;
}