vs使用Bresenham 画圆算法的完整工程

下面是在 Visual Studio 中使用 Bresenham 算法绘制圆形的完整工程：

1. 创建一个空的 Win32 控制台应用程序项目，命名为 `BresenhamCircle`。

2. 将以下代码保存为 `BresenhamCircle.cpp` 文件，并将其添加到项目中。

#include <iostream>
#include <windows.h>

using namespace std;

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    const char CLASS_NAME[] = "MyWindowClass";

    WNDCLASS wc = {};
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.lpszClassName = CLASS_NAME;

    RegisterClass(&wc);

    HWND hwnd = CreateWindowEx(
        0,
        CLASS_NAME,
        "Bresenham Circle",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
        NULL,
        NULL,
        hInstance,
        NULL
    );

    if (hwnd == NULL)
    {
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);

    MSG msg = {};
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        int x0 = ps.rcPaint.right / 2;
        int y0 = ps.rcPaint.bottom / 2;
        int r = 100;

        HPEN hPen = CreatePen(PS_SOLID, 2, RGB(255, 255, 255));
        HGDIOBJ hOldPen = SelectObject(hdc, hPen);

        int x = r, y = 0;
        int decision = 3 - 2 * r;

        while (x >= y)
        {
            // draw the eight octants
            SetPixel(hdc, x0 + x, y0 + y, RGB(255, 255, 255));
            SetPixel(hdc, x0 + y, y0 + x, RGB(255, 255, 255));
            SetPixel(hdc, x0 - y, y0 + x, RGB(255, 255, 255));
            SetPixel(hdc, x0 - x, y0 + y, RGB(255, 255, 255));
            SetPixel(hdc, x0 - x, y0 - y, RGB(255, 255, 255));
            SetPixel(hdc, x0 - y, y0 - x, RGB(255, 255, 255));
            SetPixel(hdc, x0 + y, y0 - x, RGB(255, 255, 255));
            SetPixel(hdc, x0 + x, y0 - y, RGB(255, 255, 255));

            y++;

            if (decision <= 0)
            {
                decision = decision + 4 * y + 6;
            }
            else
            {
                x--;
                decision = decision + 4 * (y - x) + 10;
            }
        }

        SelectObject(hdc, hOldPen);
        DeleteObject(hPen);

        EndPaint(hwnd, &ps);
    }
    break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }

    return 0;
}

3. 打开项目属性页，选择“配置属性”->“常规”，将“字符集”设置为“使用 Unicode 字符集”。

4. 在“链接器”->“系统”中，将“子系统”设置为“Windows (/SUBSYSTEM:WINDOWS)”。

5. 点击“确定”按钮保存项目属性设置。

6. 编译和运行程序，应该会看到一个白色的圆形在窗口中心。