Qt和DXGI进行屏幕截图并保存

答：针对 Qt，可以通过 QWidget::grab()函数截取指定 widget 内容，也可以通过 QScreen::grabWindow()函数截取整个屏幕。截取后可以用 QImage::save() 函数将截图保存为图片文件。

针对 DXGI，可以使用 Direct3D 11 的 API 来实现屏幕截图。具体步骤包括：先创建一个 ID3D11Texture2D 对象，然后将该对象绑定到当前的后台缓冲区上，接着使用 ID3D11DeviceContext::CopySubresourceRegion() 函数，将后台缓冲区的内容复制到刚刚创建的纹理对象中。最后可以使用 D3DX11SaveTextureToFile() 函数将纹理对象保存为图片文件。

相关问题

Qt和DXGI进行屏幕截图并保存示例代码

很抱歉，作为AI语言模型，我无法为您提供编写代码的实际指导。但是，我可以为您提供参考资源和示例代码，供您参考学习和应用。

以下是用Qt和DXGI进行屏幕截图并保存的示例代码：

// Qt 5.x and later with DirectX 11
QPixmap grab()
{
    ID3D11Device* device = nullptr;
    ID3D11DeviceContext* context = nullptr;
    IDXGIOutputDuplication* duplication = nullptr;
    IDXGIResource* resource = nullptr;

    QPixmap pixmap;
    QPixmap screenshot;
    RECT rect = { 0, 0, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN) };

    if (SUCCEEDED(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 0, nullptr, 0, D3D11_SDK_VERSION, &device, nullptr, &context)))
    {
        duplication = GetDuplication(device, context);
        if (duplication == nullptr)
        {
            return pixmap;
        }

        DXGI_OUTDUPL_FRAME_INFO frame_info;
        ID3D11Texture2D* texture = nullptr;
        D3D11_TEXTURE2D_DESC texture_desc;
        ZeroMemory(&texture_desc, sizeof(texture_desc));
        texture_desc.Width = rect.right - rect.left;
        texture_desc.Height = rect.bottom - rect.top;
        texture_desc.MipLevels = 1;
        texture_desc.ArraySize = 1;
        texture_desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
        texture_desc.SampleDesc.Count = 1;
        texture_desc.Usage = D3D11_USAGE_STAGING;
        texture_desc.BindFlags = 0;
        texture_desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
        texture_desc.MiscFlags = 0;

        if (FAILED(device->CreateTexture2D(&texture_desc, nullptr, &texture)))
        {
            duplication->Release();
            device->Release();
            context->Release();
            return pixmap;
        }

        POINT offset = { rect.left, rect.top };
        duplication->GetFramePointer(&frame_info, &texture, &offset);
        if (FAILED(texture->QueryInterface(IID_PPV_ARGS(&resource))))
        {
            duplication->ReleaseFrame();
            duplication->Release();
            device->Release();
            context->Release();
            texture->Release();
            return pixmap;
        }

        D3D11_MAPPED_SUBRESOURCE map_info;
        ZeroMemory(&map_info, sizeof(map_info));
        if (FAILED(context->Map(texture, 0, D3D11_MAP_READ, 0, &map_info)))
        {
            duplication->ReleaseFrame();
            duplication->Release();
            device->Release();
            context->Release();
            texture->Release();
            resource->Release();
            return pixmap;
        }

        screenshot = QPixmap::fromImage(QImage(static_cast<uchar*>(map_info.pData), texture_desc.Width, texture_desc.Height, QImage::Format_ARGB32));
        pixmap = screenshot.copy(rect);
        context->Unmap(texture, 0);

        duplication->ReleaseFrame();
        duplication->Release();
        device->Release();
        context->Release();
        texture->Release();
        resource->Release();
    }
    return pixmap;
}

IDXGIOutputDuplication* GetDuplication(ID3D11Device* device, ID3D11DeviceContext* context)
{
    IDXGIOutputDuplication* duplication = nullptr;
    IDXGIAdapter* adapter = nullptr;
    IDXGIOutput* output = nullptr;
    DXGI_OUTPUT_DESC output_desc;
    ZeroMemory(&output_desc, sizeof(output_desc));
    output_desc.Flags = DXGI_ENUMERATION_FLAG_PRIMARY;

    if (FAILED(CreateDXGIFactory(IID_PPV_ARGS(&factory)))) return nullptr;
    if (FAILED(factory->EnumAdapters(0, &adapter))) return nullptr;
    if (FAILED(adapter->EnumOutputs(0, &output))) return nullptr;
    if (FAILED(output->GetDesc(&output_desc))) return nullptr;

    D3D11_RENDER_TARGET_VIEW_DESC target_desc;
    ZeroMemory(&target_desc, sizeof(target_desc));
    target_desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    target_desc.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D;

    ID3D11Texture2D* texture = nullptr;
    if (FAILED(device->CreateTexture2D(&GetTargetDesc(output_desc.DesktopCoordinates), nullptr, &texture))) return nullptr;

    ID3D11RenderTargetView* target = nullptr;
    ID3D11Texture2D* backbuffer = nullptr;
    D3D11_TEXTURE2D_DESC desc;
    backbuffer->GetDesc(&desc);
    target_desc.Texture2D.MipSlice = 0;
    if (FAILED(device->CreateRenderTargetView(backbuffer, &target_desc, &target))) return nullptr;

    ID3D11Texture2D* stage_texture = nullptr;
    if (FAILED(device->CreateTexture2D(&desc, nullptr, &stage_texture))) return nullptr;

    ID3D11Device* device2 = nullptr;
    if (FAILED(device->QueryInterface(IID_PPV_ARGS(&device2)))) return nullptr;

    ID3D11DeviceContext* context2 = nullptr;
    if (FAILED(device2->CreateDeferredContext(0, &context2))) return nullptr;

    context2->CopyResource(stage_texture, backbuffer);
    context2->Flush();

    DXGI_OUTPUT_DESC output_desc2;
    ZeroMemory(&output_desc2, sizeof(output_desc2));
    output_desc2.Flags = DXGI_ENUMERATION_FLAG_PRIMARY;

    IDXGIOutput5* output2 = nullptr;
    adapter->EnumOutputs(0, (IDXGIOutput**)&output2);
    output2->DuplicateOutput(context, &duplication);

    return duplication;
}

此代码是用 C++ 和 Qt 框架实现的。如果您非常熟悉Qt和DXGI，那么您可能会发现此代码可能有些错误或漏洞，但这个示例应该可以为您提供一个很好的起点。请确保在尝试使用这段代码之前认真阅读并理解它，并仔细检查以确保它适合您的具体用例。

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。