C++GDI给绘制的三角形上色

要给C++中使用GDI绘制的三角形上色，可以使用GDI提供的函数来设置画刷（brush）的颜色和风格。

下面是一个示例代码，演示如何使用GDI绘制一个三角形并给其上色：

#include <windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // 创建窗口
    HWND hWnd;
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, IDI_APPLICATION);
    wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = "TriangleColoring";
    wcex.hIconSm = LoadIcon(wcex.hInstance, IDI_APPLICATION);

    if (!RegisterClassEx(&wcex))
    {
        MessageBox(NULL, "窗口注册失败！", "错误", MB_ICONERROR);
        return 1;
    }

    hWnd = CreateWindow("TriangleColoring", "Triangle Coloring Demo", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

    if (!hWnd)
    {
        MessageBox(NULL, "窗口创建失败！", "错误", MB_ICONERROR);
        return 1;
    }

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    // 消息循环
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

void DrawTriangle(HDC hdc)
{
    POINT points[3] = { {100, 100}, {200, 200}, {300, 100} };  // 定义三角形的三个顶点坐标

    // 创建画刷并设置颜色为红色
    HBRUSH hBrush = CreateSolidBrush(RGB(255, 0, 0));

    // 选择画刷
    HBRUSH hOldBrush = (HBRUSH)SelectObject(hdc,＊＊＊