qt使用dxgi截屏保存

以下是使用Qt和DXGI进行屏幕截图并保存的示例代码：

#include <QCoreApplication>
#include <QImage>
#include <QFile>
#include <QDebug>
#include <d3d11.h>
#include <dxgi1_2.h>

// Helper function to check HRESULTs
#define CHECK_HR(hr, msg) \
    if (FAILED(hr)) { \
        qDebug() << msg << "failed with HRESULT" << hr; \
        return false; \
    }

bool saveScreenshot(const QString& filePath)
{
    HRESULT hr = S_OK;

    // Create DXGI factory
    IDXGIFactory1* pFactory = nullptr;
    hr = CreateDXGIFactory1(__uuidof(IDXGIFactory1), (void**)&pFactory);
    CHECK_HR(hr, "Failed to create DXGI factory");

    // Get primary adapter
    IDXGIAdapter1* pAdapter = nullptr;
    hr = pFactory->EnumAdapters1(0, &pAdapter);
    CHECK_HR(hr, "Failed to get primary adapter");

    // Create D3D device and swap chain
    D3D_FEATURE_LEVEL featureLevel = D3D_FEATURE_LEVEL_11_0;
    D3D_FEATURE_LEVEL featureLevels[] = { featureLevel };
    DXGI_SWAP_CHAIN_DESC swapChainDesc = { 0 };
    swapChainDesc.BufferCount = 1;
    swapChainDesc.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapChainDesc.OutputWindow = GetDesktopWindow();
    swapChainDesc.SampleDesc.Count = 1;
    swapChainDesc.Windowed = TRUE;
    ID3D11Device* pDevice = nullptr;
    ID3D11DeviceContext* pContext = nullptr;
    IDXGISwapChain* pSwapChain = nullptr;
    hr = D3D11CreateDeviceAndSwapChain(pAdapter, D3D_DRIVER_TYPE_UNKNOWN, NULL, 0, featureLevels, 1,
        D3D11_SDK_VERSION, &swapChainDesc, &pSwapChain, &pDevice, &featureLevel, &pContext);
    CHECK_HR(hr, "Failed to create D3D device and swap chain");

    // Get back buffer texture
    ID3D11Texture2D* pBackBuffer = nullptr;
    hr = pSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
    CHECK_HR(hr, "Failed to get back buffer texture");

    // Create a CPU-readable texture
    D3D11_TEXTURE2D_DESC textureDesc = { 0 };
    textureDesc.Width = GetSystemMetrics(SM_CXSCREEN);
    textureDesc.Height = GetSystemMetrics(SM_CYSCREEN);
    textureDesc.MipLevels = 1;
    textureDesc.ArraySize = 1;
    textureDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    textureDesc.SampleDesc.Count = 1;
    textureDesc.Usage = D3D11_USAGE_STAGING;
    textureDesc.BindFlags = 0;
    textureDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
    ID3D11Texture2D* pTexture = nullptr;
    hr = pDevice->CreateTexture2D(&textureDesc, NULL, &pTexture);
    CHECK_HR(hr, "Failed to create CPU-readable texture");

    // Copy back buffer to CPU-readable texture
    pContext->CopyResource(pTexture, pBackBuffer);

    // Read texture data
    D3D11_MAPPED_SUBRESOURCE mappedResource;
    hr = pContext->Map(pTexture, 0, D3D11_MAP_READ, 0, &mappedResource);
    CHECK_HR(hr, "Failed to map texture");
    QImage image(mappedResource.pData, textureDesc.Width, textureDesc.Height, QImage::Format_RGB32);
    pContext->Unmap(pTexture, 0);

    // Save image to file
    if (!image.save(filePath)) {
        qDebug() << "Failed to save screenshot to" << filePath;
        return false;
    }

    // Cleanup
    pContext->Release();
    pDevice->Release();
    pSwapChain->Release();
    pAdapter->Release();
    pFactory->Release();
    pTexture->Release();
    pBackBuffer->Release();

    return true;
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    if (saveScreenshot("screenshot.png")) {
        qDebug() << "Screenshot saved to screenshot.png";
    }

    return a.exec();
}

该代码使用DXGI和D3D11 API创建设备和交换链，然后获取主适配器和后缓冲器纹理。然后，它创建一个CPU可读的纹理，将后缓冲器纹理复制到该纹理中，然后将其映射到内存中以获取图像数据。最后，它使用Qt的QImage类将图像数据保存到文件中。请注意，此代码需要使用Windows SDK和DirectX SDK来构建。