Rastreamento de código QR (C# e C++)
Antes de começar aqui, recomendamos que você dê uma olhada em nosso artigo de visão geral do rastreamento de código QR, que contém uma visão geral, uma tabela de suporte do dispositivo e práticas recomendadas.
Obtendo o pacote QR
Você pode baixar o pacote NuGet para detecção de código QR aqui.
Detecção de códigos QR
Adicionando o recurso de webcam
Você precisará adicionar a funcionalidade webcam ao seu manifesto para detectar códigos QR. Esse recurso é necessário, pois os dados nos códigos detectados no ambiente do usuário podem conter informações confidenciais.
A permissão pode ser solicitada ligando para QRCodeWatcher.RequestAccessAsync():
C#:
await QRCodeWatcher.RequestAccessAsync();
C++:
co_await QRCodeWatcher.RequestAccessAsync();
A permissão deve ser solicitada antes de construir um objeto QRCodeWatcher.
Embora a detecção de código QR exija o webcam recurso, a detecção ocorre usando as câmeras de rastreamento do dispositivo. Isso fornece um FOV de detecção mais amplo e melhor duração da bateria em comparação com a detecção com a câmera de foto/vídeo (PV) do dispositivo.
Detectando códigos QR em C++
using namespace winrt::Windows::Foundation;
using namespace winrt::Microsoft::MixedReality::QR;
class QRListHelper
{
public:
QRListHelper(MyApplication& app) :
m_app(app)
{}
IAsyncAction SetUpQRCodes()
{
if (QRCodeWatcher::IsSupported())
{
QRCodeWatcherAccessStatus status = co_await QRCodeWatcher::RequestAccessAsync();
InitializeQR(status);
}
}
private:
void OnAddedQRCode(const IInspectable&, const QRCodeAddedEventArgs& args)
{
m_app.OnAddedQRCode(args);
}
void OnUpdatedQRCode(const IInspectable&, const QRCodeUpdatedEventArgs& args)
{
m_app.OnUpdatedQRCode(args);
}
void OnEnumerationComplete(const IInspectable&, const IInspectable&)
{
m_app.OnEnumerationComplete();
}
MyApplication& m_app;
QRCodeWatcher m_qrWatcher{ nullptr };
void InitializeQR(QRCodeWatcherAccessStatus status)
{
if (status == QRCodeWatcherAccessStatus::Allowed)
{
m_qrWatcher = QRCodeWatcher();
m_qrWatcher.Added({ this, &QRListHelper::OnAddedQRCode });
m_qrWatcher.Updated({ this, &QRListHelper::OnUpdatedQRCode });
m_qrWatcher.EnumerationCompleted({ this, &QRListHelper::OnEnumerationComplete });
m_qrWatcher.Start();
}
else
{
// Permission denied by system or user
// Handle the failures
}
}
};
Obtendo o sistema de coordenadas para um código QR
Cada código QR detectado expõe um sistema de coordenadas espaciais alinhado com o código QR no canto superior esquerdo do quadrado de detecção rápida no canto superior esquerdo:
Ao usar diretamente o QR SDK, o eixo Z está apontando para o papel (não mostrado).
O SpatialCoordinateSystem de um código QR se alinha conforme mostrado. Você pode obter o sistema de coordenadas da plataforma chamando SpatialGraphInteropPreview::CreateCoordinateSystemForNode e passando o SpatialGraphNodeId do código.
O código C++ abaixo mostra como criar um retângulo e colocá-lo usando o sistema de coordenadas do código QR:
// Creates a 2D rectangle in the x-y plane, with the specified properties.
std::vector<float3> MyApplication::CreateRectangle(float width, float height)
{
std::vector<float3> vertices(4);
vertices[0] = { 0, 0, 0 };
vertices[1] = { width, 0, 0 };
vertices[2] = { width, height, 0 };
vertices[3] = { 0, height, 0 };
return vertices;
}
Você pode usar o tamanho físico para criar o retângulo QR:
std::vector<float3> qrVertices = CreateRectangle(code.PhysicalSideLength(), code.PhysicalSideLength());
O sistema de coordenadas pode ser usado para desenhar o código QR ou anexar hologramas ao local:
using namespace winrt::Windows::Perception::Spatial;
using namespace winrt::Windows::Perception::Spatial::Preview;
SpatialCoordinateSystem qrCoordinateSystem = SpatialGraphInteropPreview::CreateCoordinateSystemForNode(code.SpatialGraphNodeId());
Ao todo, seu QRCodeAddedHandler pode ser algo assim:
void MyApplication::OnAddedQRCode(const QRCodeAddedEventArgs& args)
{
QRCode code = args.Code();
std::vector<float3> qrVertices = CreateRectangle(code.PhysicalSideLength(), code.PhysicalSideLength());
std::vector<unsigned short> qrCodeIndices = TriangulatePoints(qrVertices);
XMFLOAT3 qrAreaColor = XMFLOAT3(DirectX::Colors::Aqua);
SpatialCoordinateSystem qrCoordinateSystem = SpatialGraphInteropPreview::CreateCoordinateSystemForNode(code.SpatialGraphNodeId());
std::shared_ptr<SceneObject> m_qrShape =
std::make_shared<SceneObject>(
m_deviceResources,
qrVertices,
qrCodeIndices,
qrAreaColor,
qrCoordinateSystem);
m_sceneController->AddSceneObject(m_qrShape);
}
Referência da API de rastreamento de código QR
namespace Microsoft.MixedReality.QR
{
/// <summary>
/// Represents a detected QR code.
/// </remarks>
public class QRCode
{
/// <summary>
/// Unique id that identifies this QR code for this session.
/// </summary>
public Guid Id { get; }
/// <summary>
/// Spatial graph node id for this QR code to create a coordinate system.
/// </summary>
public Guid SpatialGraphNodeId { get; }
/// <summary>
/// Version of this QR code. Version 1-40 are regular QR codes and M1 to M4 are Micro QR code formats 1-4.
/// </summary>
public QRVersion Version { get; }
/// <summary>
/// Physical width and height of this QR code in meters.
/// </summary>
public float PhysicalSideLength { get; }
/// <summary>
/// Decoded QR code data.
/// </summary>
public String Data { get; }
/// <summary>
/// Size of the RawData of this QR code.
/// </summary>
public UInt32 RawDataSize { get; }
/// <summary>
/// Gets the error-corrected raw data bytes.
/// Used when the platform is unable to decode the code's format,
/// allowing your app to decode as needed.
/// </summary>
public void GetRawData(byte[] buffer);
/// <summary>
/// The last detected time in 100ns QPC ticks.
/// </summary>
public System.TimeSpan SystemRelativeLastDetectedTime { get; }
/// <summary>
/// The last detected time.
/// </summary>
public System.DateTimeOffset LastDetectedTime { get; }
}
/// <summary>
/// Event arguments for a QRCodeWatcher's Added event.
/// </summary>
public class QRCodeAddedEventArgs
{
/// <summary>
/// Gets the QR Code that was added
/// </summary>
public QRCode Code { get; }
}
/// <summary>
/// Event arguments for a QRCodeWatcher's Removed event.
/// </summary>
public class QRCodeRemovedEventArgs
{
/// <summary>
/// Gets the QR Code that was removed.
/// </summary>
public QRCode Code { get; }
}
/// <summary>
/// Event arguments for a QRCodeWatcher's Updated event.
/// </summary>
public class QRCodeUpdatedEventArgs
{
/// <summary>
/// Gets the QR Code that was updated.
/// </summary>
public QRCode Code { get; }
}
/// <summary>
/// Represents the status of an access request for QR code detection.
/// </summary>
public enum QRCodeWatcherAccessStatus
{
/// <summary>
/// The system has denied permission for the app to detect QR codes.
/// </summary>
DeniedBySystem = 0,
/// <summary>
/// The app has not declared the webcam capability in its manifest.
/// </summary>
NotDeclaredByApp = 1,
/// <summary>
/// The user has denied permission for the app to detect QR codes.
/// </summary>
DeniedByUser = 2,
/// <summary>
/// A user prompt is required to get permission to detect QR codes.
/// </summary>
UserPromptRequired = 3,
/// <summary>
/// The user has given permission to detect QR codes.
/// </summary>
Allowed = 4,
}
/// <summary>
/// Detects QR codes in the user's environment.
/// </summary>
public class QRCodeWatcher
{
/// <summary>
/// Gets whether QR code detection is supported on the current device.
/// </summary>
public static bool IsSupported();
/// <summary>
/// Request user consent before using QR code detection.
/// </summary>
public static IAsyncOperation<QRCodeWatcherAccessStatus> RequestAccessAsync();
/// <summary>
/// Constructs a new QRCodeWatcher.
/// </summary>
public QRCodeWatcher();
/// <summary>
/// Starts detecting QR codes.
/// </summary>
/// <remarks>
/// Start should only be called once RequestAccessAsync has succeeded.
/// Start should not be called if QR code detection is not supported.
/// Check that IsSupported returns true before calling Start.
/// </remarks>
public void Start();
/// <summary>
/// Stops detecting QR codes.
/// </summary>
public void Stop();
/// <summary>
/// Get the list of QR codes detected.
/// </summary>
/// <remarks>
/// </remarks>
public IList<QRCode> GetList();
/// <summary>
/// Event representing the addition of a QR Code.
/// </summary>
public event EventHandler<QRCodeAddedEventArgs> Added;
/// <summary>
/// Event representing the removal of a QR Code.
/// </summary>
public event EventHandler<QRCodeRemovedEventArgs> Removed;
/// <summary>
/// Event representing the update of a QR Code.
/// </summary>
public event EventHandler<QRCodeUpdatedEventArgs> Updated;
/// <summary>
/// Event representing the enumeration of QR Codes completing after a Start call.
/// </summary>
public event EventHandler<Object> EnumerationCompleted;
}
/// <summary>
/// Version info for QR codes, including Micro QR codes.
/// </summary>
public enum QRVersion
{
QR1 = 1,
QR2 = 2,
QR3 = 3,
QR4 = 4,
QR5 = 5,
QR6 = 6,
QR7 = 7,
QR8 = 8,
QR9 = 9,
QR10 = 10,
QR11 = 11,
QR12 = 12,
QR13 = 13,
QR14 = 14,
QR15 = 15,
QR16 = 16,
QR17 = 17,
QR18 = 18,
QR19 = 19,
QR20 = 20,
QR21 = 21,
QR22 = 22,
QR23 = 23,
QR24 = 24,
QR25 = 25,
QR26 = 26,
QR27 = 27,
QR28 = 28,
QR29 = 29,
QR30 = 30,
QR31 = 31,
QR32 = 32,
QR33 = 33,
QR34 = 34,
QR35 = 35,
QR36 = 36,
QR37 = 37,
QR38 = 38,
QR39 = 39,
QR40 = 40,
MicroQRM1 = 41,
MicroQRM2 = 42,
MicroQRM3 = 43,
MicroQRM4 = 44,
}
}