ScreenGrab

A Direct3D 11 2D texture save routine for generating a "screenshot" from a render target texture. There is a function that will dump the 2D texture to a .DDS file, and another that will write using WIC (BMP, JPEG, PNG, TIFF, GIF, JPEG-XR / HD Photo, or other WIC supported file container).

These writers do not support array textures, 1D textures, 3D volume textures, cubemaps, or cubemap arrays. Mipmaps are also ignored. For those scenarios, use the DirectXTex library functionality. The ScreenGrab module is really designed to make a quick and light-weight solution for capturing screenshots at runtime.

MSAA textures are resolved before being written.

A standalone version is included in the DirectXTex package.

Header

#include <ScreenGrab.h>

Initialization

The library assumes that the client code will have already called CoInitialize, CoInitializeEx, or Windows::Foundation::Initialize as needed by the application before calling any Windows Imaging Component functionality.

For a Universal Windows Platform (UWP) app using /ZW, the Windows Runtime and COM is initialized by the C/C++ Run-Time. For C++/WinRT applications, this is done by calling winrt::init_apartment();.

For a classic Windows desktop application you have to do this explicitly:

#if (_WIN32_WINNT >= 0x0A00 /*_WIN32_WINNT_WIN10*/)
    Microsoft::WRL::Wrappers::RoInitializeWrapper initialize(RO_INIT_MULTITHREADED);
    if (FAILED(initialize))
        // error
#else
    HRESULT hr = CoInitializeEx(nullptr, COINITBASE_MULTITHREADED);
    if (FAILED(hr))
        // error
#endif

Functions

SaveDDSTextureToFile

Saves a texture to a DDS file on disk. It performs no format conversions, but will try to favor writing legacy .DDS files when possible for improved tool support.

HRESULT SaveDDSTextureToFile(ID3D11DeviceContext* pContext,
    ID3D11Resource* pSource, LPCWSTR fileName );

SaveWICTextureToFile

Saves a texture to a WIC-supported bitmap file on disk. The caller provides the desired WIC container format via guidContainerFormat and can optionally specify a desired WIC pixel format via targetFormat (which will result in E_FAIL if the requested pixel format is not supported by the WIC codec). If no WIC pixel format GUID is provided as the targetFormat parameter, it will default to a non-alpha format since 'screenshots' usually ignore the alpha channel in render targets.

HRESULT SaveWICTextureToFile( ID3D11DeviceContext* pContext,
    ID3D11Resource* pSource,
    REFGUID guidContainerFormat,
    LPCWSTR fileName,
    const GUID* targetFormat = nullptr,
    std::function<void(IPropertyBag2*)> setCustomProps = nullptr,
    bool forceSRGB = false );

Examples

This example saves a DDS screenshot and a JPEG screenshot given an immediate device context and swapchain backbuffer.

using namespace DirectX;
using namespace Microsoft::WRL;

ComPtr<ID3D11Texture2D> backBuffer;
HRESULT hr = swapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ),
   reinterpret_cast<LPVOID*>( backBuffer.GetAddressOf() ) );
if ( SUCCEEDED(hr) )
{
    hr = SaveDDSTextureToFile( immContext.Get(), backBuffer.Get(),
             L"SCREENSHOT.DDS" );
    DX::ThrowIfFailed(hr);

    hr = SaveWICTextureToFile( immContext.Get(), backBuffer.Get(),
             GUID_ContainerFormatJpeg, L"SCREENSHOT.JPG" );
}
DX::ThrowIfFailed(hr);

Here is an example of explicitly writing a screenshot as a 16-bit (5:6:5) BMP.

...
hr = SaveWICTextureToFile( immContext.Get(), backBuffer.Get(),
        GUID_ContainerFormatBmp, L"SCREENSHOT.BMP",
        &GUID_WICPixelFormat16bppBGR565 );

When writing WIC files, you can also provide a callback for setting specific encoding options.

...
hr = SaveWICTextureToFile( immContext.Get(), backBuffer.Get(),
         GUID_ContainerFormatTiff, L"SCREENSHOT.TIF", nullptr,
         [&](IPropertyBag2* props)
         {
             PROPBAG2 options[2] = { 0, 0 };
             options[0].pstrName = const_cast<wchar_t*>(L"CompressionQuality");
             options[1].pstrName = const_cast<wchar_t*>(L"TiffCompressionMethod");

             VARIANT varValues[2];
             varValues[0].vt = VT_R4;
             varValues[0].fltVal = 0.75f;

             varValues[1].vt = VT_UI1;
             varValues[1].bVal = WICTiffCompressionNone;

             (void)props->Write( 2, options, varValues );
          });

sRGB vs. Linear Color Space

With the modern presentation flip models, you don't actually use DXGI_FORMAT_*_SRGB with the backbuffer format. You only use it with the render target view if doing gamma-correct rendering. Therefore, when writing PNG screenshots directly from the swapchain backbuffer you can end up with a washed-out image. You solve this by using the optional parameter forceSRGB to influence the image metadata:

hr = SaveWICTextureToFile( immContext.Get(), backBuffer.Get(),
    GUID_ContainerFormatPng, L"SCREENSHOT.PNG",
    nullptr, nullptr, true );

Release Notes

• JPEG-XR / HD Photo supports nearly all WIC pixel formats including floating-point for both encoding and decoding.

• TIFF can contain floating-point data (128bpp or 96bpp), but the WIC built-in codec can only decode such images. It always converts floating-point data to unorm when encoding.

• Paletted WIC formats are not supported for writing by the SaveWICTextureToFile function.

• When writing PNG files, if the input image format is DXGI_FORMAT_*_SRGB, then the resulting file will have the sRGB rendering intent chunk. Otherwise, it will not have the sRGB chunk and instead will have an explicit gAMA chunk of 1.0.

WIC2

WIC2 is available on Windows 10, Windows 8.x, and on Windows 7 Service Pack 1 with KB 2670838 installed.

• If WIC2 is supported, then this function can make use of the new WIC pixel format GUID_WICPixelFormat96bppRGBFloat.

See Windows Imaging Component and Windows 8

Windows Store apps

For Save*TextureToFile to succeed, the application must have write access to the destination path. For Windows Store apps and Universal Windows Platform (UWP) app, the file access permissions are rather restricted so you'll need to make sure you use a fully qualified path to a valid write folder. A good location to use is the app data folder:

C++/CX

auto folder = Windows::Storage::ApplicationData::Current->LocalFolder;
// use folder->Path->Data() as the path base

C++/WinRT

#include "winrt/Windows.Storage.h"
auto folder = winrt::Windows::Storage::ApplicationData::Current().LocalFolder();
// use folder.Path().c_str() as the path base

If you are going to immediately copy it to another location via StorageFolder::MoveAndReplaceAsync, then use the app's temporary folder:

C++/CX

#include <ppltasks.h>
using namespace concurrency;

using Windows::Storage;
using Windows::Storage::Pickers;

auto folder = ApplicationData::Current->TemporaryFolder;

wchar_t fname[ _MAX_PATH ];
wcscpy_s( fname, folder->Path->Data() );
wcscat_s( fname, L"\\screenshot.jpg" );

// note that context use is not thread-safe
HRESULT hr = SaveWICTextureToFile( immContext.Get(), backBuffer.Get(),
    GUID_ContainerFormatJpeg, fname  );

DX::ThrowIfFailed(hr);

auto jpegExtensions = ref new Platform::Collections::Vector<String^>();
jpegExtensions->Append(".jpg");

auto pngExtensions = ref new Platform::Collections::Vector<String^>();
pngExtensions->Append(".png");

auto savePicker = ref new FileSavePicker();
savePicker->SuggestedStartLocation = PickerLocationId.PicturesLibrary;
savePicker->FileTypeChoices->Insert("Joint Photographic Experts Group", jpegExtensions);
savePicker->FileTypeChoices->Insert("Portable Network Graphics", pngExtensions);
savePicker->SuggestedFileName = "Screenshot";

create_task(savePicker->PickSaveFileAsync()).then([](StorageFile^ file)
{
    if ( file )
    {
        auto folder = Windows::Storage::ApplicationData::Current->TemporaryFolder;
        auto task = create_task( folder->GetFileAsync("screenshot.jpg") );
        task.then([file](StorageFile^ tempFile) ->IAsyncAction^
        {
            return tempFile->MoveAndReplaceAsync( file );
        });
    }
});

C++/WinRT

#include "winrt/Windows.Storage.h"
#include "winrt/Windows.Storage.Pickers.h"

using namespace winrt::Windows::Storage;
using namespace winrt::Windows::Storage::Pickers;

auto folder = ApplicationData::Current().TemporaryFolder();

wchar_t fname[_MAX_PATH];
wcscpy_s(fname, folder.Path().c_str());
wcscat_s(fname, L"\\screenshot.jpg");

// note that context use is not thread-safe
HRESULT hr = SaveWICTextureToFile(immContext.Get(), backBuffer.Get(),
    GUID_ContainerFormatJpeg, fname);

DX::ThrowIfFailed(hr);

FileSavePicker savePicker;
savePicker.SuggestedStartLocation(PickerLocationId::PicturesLibrary);
savePicker.FileTypeChoices().Insert(L"Joint Photographic Experts Group", winrt::single_threaded_vector<winrt::hstring>({ L".jpg" }));
savePicker.FileTypeChoices().Insert(L"Portable Network Graphics", winrt::single_threaded_vector<winrt::hstring>({ L".png" }));
savePicker.SuggestedFileName(L"Screenshot");

auto file = co_await savePicker.PickSaveFileAsync();
if (file)
{
    auto tempFolder = ApplicationData::Current().TemporaryFolder();
    auto tempFile = co_await file.CopyAsync(tempFolder, file.Name(), NameCollisionOption::GenerateUniqueName);
    if (tempFile)
    {
        co_await tempFile.MoveAndReplaceAsync(file);
    }
}

See File access and permissions (Windows Runtime apps), ApplicationData.TemporaryFolder property

Xbox One

When using Direct3D 11.x fast semantics and trying to capture a Render Target, it must be decompressed with DecompressResource before calling SaveDDSTextureToFile or SaveWICTextureToFile. The save functions will block until the resource copy is completed, so it should not be used with high frequency.