c++ 生成一个窗口并把base64图像展示出来 不使用qt 使用GDI+

好的，以下是一个使用 GDI+ 在 C++ 中生成窗口并展示 base64 图像的示例代码：

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

#pragma comment (lib,"Gdiplus.lib")

using namespace Gdiplus;
using namespace std;

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    HWND hwnd;
    MSG msg;
    WNDCLASS wndclass;
    GdiplusStartupInput gdiplusStartupInput;
    ULONG_PTR gdiplusToken;

    // Initialize GDI+
    GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

    // Register the main window class
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = TEXT("Base64ImageDisplay");

    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"), TEXT("Error"), MB_ICONERROR);
        return 0;
    }

    // Create the main window
    hwnd = CreateWindow(TEXT("Base64ImageDisplay"), TEXT("Base64 Image Display"),
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
        640, 480, NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    // Enter the message loop
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    // Shutdown GDI+
    GdiplusShutdown(gdiplusToken);
    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    PAINTSTRUCT ps;
    HDC hdc;
    WCHAR* base64Image = L"iVBORw0KGgoAAAANSUhEUgAAABAAAAAQEAYAAABPYyMiAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVDhPYxgF/mYAAICDAv6iURfAAAAAElFTkSuQmCC";

    switch (message)
    {
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        Graphics graphics(hdc);

        // Decode base64 image
        ULONG size = 0;
        BYTE* bytes = NULL;
        Base64Decode((const char*)base64Image, &bytes, &size);

        // Load image from memory
        HGLOBAL hMem = GlobalAlloc(GMEM_MOVEABLE, size);
        LPVOID pMem = GlobalLock(hMem);
        memcpy(pMem, bytes, size);
        IStream* pStream = NULL;
        CreateStreamOnHGlobal(hMem, FALSE, &pStream);
        Image image(pStream);

        // Draw image
        graphics.DrawImage(&image, 0, 0, 640, 480);

        // Cleanup
        GlobalUnlock(hMem);
        GlobalFree(hMem);
        delete[] bytes;

        EndPaint(hwnd, &ps);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hwnd, message, wParam, lParam);
    }
    return 0;
}

该代码会创建一个名为 "Base64ImageDisplay" 的窗口，并在其中展示一个 base64 编码的图片。你可以将 `base64Image` 替换为你自己的 base64 图片字符串。

注意：此处使用了 GDI+ 库和 base64 解码函数 `Base64Decode()`，需要在编译时链接 GDI+ 库并包含 base64 解码函数的实现。