XamlCompositionBrushBase 類別

參考

定義

命名空間:: Windows.UI.Xaml.Media

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

編輯

提供基類，用來建立使用 CompositionBrush繪製區域的 XAML 筆刷。

public ref class XamlCompositionBrushBase : Brush

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 262144)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class XamlCompositionBrushBase : Brush

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 262144)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public class XamlCompositionBrushBase : Brush

Public Class XamlCompositionBrushBase
Inherits Brush

繼承: Object Platform::Object IInspectable DependencyObject Brush XamlCompositionBrushBase

衍生: Windows.UI.Xaml.Media.AcrylicBrush

Windows.UI.Xaml.Media.RevealBrush

屬性: ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Windows 需求

裝置系列	Windows 10 Creators Update (已於 10.0.15063.0 引進)
API contract	Windows.Foundation.UniversalApiContract (已於 v4.0 引進)

範例

此範例顯示自訂筆刷的定義，該筆刷會繪製 UIElement 後方之模糊複本，其中筆刷會使用 Win2D 模糊效果和 CompositionBackdropBrush來套用：

public sealed class BackdropBlurBrush : XamlCompositionBrushBase
{
    public static readonly DependencyProperty BlurAmountProperty = DependencyProperty.Register(
        "BlurAmount",
        typeof(double),
        typeof(BackdropBlurBrush),
        new PropertyMetadata(0.0, new PropertyChangedCallback(OnBlurAmountChanged)
        )
    );

    public double BlurAmount
    {
        get { return (double)GetValue(BlurAmountProperty); }
        set { SetValue(BlurAmountProperty, value); }
    }

    private static void OnBlurAmountChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var brush = (BackdropBlurBrush)d;
        // Unbox and set a new blur amount if the CompositionBrush exists.
        brush.CompositionBrush?.Properties.InsertScalar("Blur.BlurAmount", (float)(double)e.NewValue);            
    }

    public BackdropBlurBrush()
    {
    }

    protected override void OnConnected()
    {
        // Delay creating composition resources until they're required.
        if (CompositionBrush == null)
        {
            var backdrop = Window.Current.Compositor.CreateBackdropBrush();                

            // Use a Win2D blur affect applied to a CompositionBackdropBrush.
            var graphicsEffect = new GaussianBlurEffect
            {
                Name = "Blur",
                BlurAmount = (float)this.BlurAmount,
                Source = new CompositionEffectSourceParameter("backdrop")
            };

            var effectFactory = Window.Current.Compositor.CreateEffectFactory(graphicsEffect, new[] { "Blur.BlurAmount" });
            var effectBrush = effectFactory.CreateBrush();

            effectBrush.SetSourceParameter("backdrop", backdrop);

            CompositionBrush = effectBrush;
        }
    }

    protected override void OnDisconnected()
    {
        // Dispose of composition resources when no longer in use.
        if (CompositionBrush != null)
        {
            CompositionBrush.Dispose();
            CompositionBrush = null;
        }
    }
}

Public NotInheritable Class BackdropBlurBrush
    Inherits XamlCompositionBrushBase

    Public Shared ReadOnly BlurAmountProperty As DependencyProperty = DependencyProperty.Register(
            "BlurAmount",
            GetType(Double),
            GetType(BackdropBlurBrush),
            New PropertyMetadata(0.0, New PropertyChangedCallback(AddressOf OnBlurAmountChanged)
            )
        )

    Public Property BlurAmount As Double
        Get
            Return DirectCast(GetValue(BlurAmountProperty), Double)
        End Get
        Set
            SetValue(BlurAmountProperty, Value)
        End Set
    End Property

    Private Shared Sub OnBlurAmountChanged(d As DependencyObject, e As DependencyPropertyChangedEventArgs)
        Dim brush = DirectCast(d, BackdropBlurBrush)
        ' Unbox And set a New blur amount if the CompositionBrush exists.
        brush.CompositionBrush?.Properties.InsertScalar("Blur.BlurAmount", Convert.ToSingle(DirectCast(e.NewValue, Double)))
    End Sub

    Protected Overrides Sub OnConnected()
        If Me.CompositionBrush Is Nothing Then

            Dim backdrop As CompositionBackdropBrush = Window.Current.Compositor.CreateBackdropBrush()

            ' Use a Win2D blur affect applied to a CompositionBackdropBrush.
            Dim graphicsEffect As GaussianBlurEffect = New GaussianBlurEffect()
            graphicsEffect.Name = "Blur"
            graphicsEffect.BlurAmount = Me.BlurAmount
            graphicsEffect.Source = New CompositionEffectSourceParameter("backdrop")

            Dim effectFactory As CompositionEffectFactory = Window.Current.Compositor.CreateEffectFactory(graphicsEffect, New String() {"Blur.BlurAmount"})
            Dim effectBrush As CompositionEffectBrush = effectFactory.CreateBrush()

            effectBrush.SetSourceParameter("backdrop", backdrop)

            CompositionBrush = effectBrush
        End If
    End Sub

    Protected Overrides Sub OnDisconnected()
        ' Dispose of composition resources when no longer in use.
        If CompositionBrush IsNot Nothing Then
            CompositionBrush.Dispose()
            CompositionBrush = Nothing
        End If
    End Sub
End Class

針對下列 C++/WinRT 程式碼範例，您必須將 Midl 檔案 (.idl) 檔案新增至您的專案。

// BackdropBlurBrush.idl
namespace MyApp
{
    [default_interface]
    runtimeclass BackdropBlurBrush : Windows.UI.Xaml.Media.XamlCompositionBrushBase
    {
        BackdropBlurBrush();
        static Windows.UI.Xaml.DependencyProperty BlurAmountProperty{ get; };
        Double BlurAmount;
    }
}

// pch.h
// You'll need to install the Microsoft Win2D NuGet package for this code example.
#include <winrt/Microsoft.Graphics.Canvas.Effects.h>
#include <winrt/Windows.Graphics.Effects.h>

// BackdropBlurBrush.h.
struct BackdropBlurBrush : BackdropBlurBrushT<BackdropBlurBrush>
{
    BackdropBlurBrush() = default;

    static Windows::UI::Xaml::DependencyProperty BlurAmountProperty() { return m_blurAmountProperty; }

    double BlurAmount()
    {
        return winrt::unbox_value<double>(GetValue(m_blurAmountProperty));
    }

    void BlurAmount(double value)
    {
        SetValue(m_blurAmountProperty, winrt::box_value(value));
    }

    void OnConnected();
    void OnDisconnected();

    static void OnBlurAmountChanged(Windows::UI::Xaml::DependencyObject const& d, Windows::UI::Xaml::DependencyPropertyChangedEventArgs const& e);

private:
    static Windows::UI::Xaml::DependencyProperty m_blurAmountProperty;
};

// WindowBlurBrush.cpp.
Windows::UI::Xaml::DependencyProperty BackdropBlurBrush::m_blurAmountProperty =
    Windows::UI::Xaml::DependencyProperty::Register(
        L"BlurAmount",
        winrt::xaml_typename<double>(),
        winrt::xaml_typename<MyApp::BackdropBlurBrush>(),
        Windows::UI::Xaml::PropertyMetadata{ winrt::box_value(0.), Windows::UI::Xaml::PropertyChangedCallback{ &BackdropBlurBrush::OnBlurAmountChanged } }
);

void BackdropBlurBrush::OnBlurAmountChanged(Windows::UI::Xaml::DependencyObject const& d, Windows::UI::Xaml::DependencyPropertyChangedEventArgs const& e)
{
    auto brush{ d.as<MyApp::BackdropBlurBrush>() };
    // Unbox and set a new blur amount if the CompositionBrush exists.
    if (brush.CompositionBrush() != nullptr)
    {
        brush.CompositionBrush().Properties().InsertScalar(L"Blur.BlurAmount", (float)winrt::unbox_value<double>(e.NewValue()));
    }
}

void BackdropBlurBrush::OnConnected()
{
    // Delay creating composition resources until they're required.
    if (!CompositionBrush())
    {
        auto backdrop{ Windows::UI::Xaml::Window::Current().Compositor().CreateBackdropBrush() };

        // Use a Win2D blur affect applied to a CompositionBackdropBrush.
        Microsoft::Graphics::Canvas::Effects::GaussianBlurEffect graphicsEffect{};
        graphicsEffect.Name(L"Blur");
        graphicsEffect.BlurAmount(this->BlurAmount());
        graphicsEffect.Source(Windows::UI::Composition::CompositionEffectSourceParameter(L"backdrop"));

        auto effectFactory{ Windows::UI::Xaml::Window::Current().Compositor().CreateEffectFactory(graphicsEffect, { L"Blur.BlurAmount" }) };
        auto effectBrush{ effectFactory.CreateBrush() };

        effectBrush.SetSourceParameter(L"backdrop", backdrop);

        CompositionBrush(effectBrush);
    }
}

void BackdropBlurBrush::OnDisconnected()
{
    // Dispose of composition resources when no longer in use.
    if (CompositionBrush())
    {
        CompositionBrush(nullptr);
    }
}

// WindowBlurBrush.h:
public ref class BackdropBlurBrush sealed :
    public Windows::UI::Xaml::Media::XamlCompositionBrushBase
{
public:
    BackdropBlurBrush();

    static property Windows::UI::Xaml::DependencyProperty^ BlurAmountProperty
    {
        Windows::UI::Xaml::DependencyProperty^ get() { return m_blurAmountProperty; }
    };

    property double BlurAmount
    {
        double get() 
        {
            return static_cast<double>(GetValue(BlurAmountProperty));
        }
        void set(double value) 
        {
            SetValue(BlurAmountProperty, value);
        }
    };

protected:
    virtual void OnConnected() override;
    virtual void OnDisconnected() override;	
    private:
    static Windows::UI::Xaml::DependencyProperty^ m_blurAmountProperty;
    static void OnBlurAmountChanged(Windows::UI::Xaml::DependencyObject^ d, Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ e);
};

// WindowBlurBrush.cpp:
DependencyProperty^ BackdropBlurBrush::m_blurAmountProperty = DependencyProperty::Register(
    "BlurAmount",
    Platform::String::typeid,
    BackdropBlurBrush::typeid,
    ref new PropertyMetadata(0.0, ref new PropertyChangedCallback(OnBlurAmountChanged))
);

BackdropBlurBrush::BackdropBlurBrush()
{
}

void BackdropBlurBrush::OnBlurAmountChanged(DependencyObject^ d, DependencyPropertyChangedEventArgs^ e)
{
    auto brush = static_cast<BackdropBlurBrush^>(d);
    // Unbox and set a new blur amount if the CompositionBrush exists
    if (brush->CompositionBrush != nullptr)
    {
        brush->CompositionBrush->Properties->InsertScalar("Blur.BlurAmount", (float)static_cast<double>(e->NewValue));
    }
}

void BackdropBlurBrush::OnConnected()
{
    // Delay creating composition resources until they're required
    if (CompositionBrush == nullptr)
    {
        auto backdrop = Window::Current->Compositor->CreateBackdropBrush();

        // Use a Win2D blur affect applied to a CompositionBackdropBrush
        auto graphicsEffect = ref new GaussianBlurEffect();
        graphicsEffect->Name = "Blur";
        graphicsEffect->BlurAmount = static_cast<float>(this->BlurAmount);
        graphicsEffect->Source = ref new CompositionEffectSourceParameter("backdrop");

        auto animatableProperties = ref new Platform::Collections::Vector<Platform::String^>();
        animatableProperties->Append("Blur.BlurAmount");

        auto effectFactory = Window::Current->Compositor->CreateEffectFactory(graphicsEffect, animatableProperties);
        auto effectBrush = effectFactory->CreateBrush();

        effectBrush->SetSourceParameter("backdrop", backdrop);

        CompositionBrush = effectBrush;
    }
}

void BackdropBlurBrush::OnDisconnected()
{
    // Dispose of composition resources when no longer in use
    if (CompositionBrush != nullptr)
    {
        delete CompositionBrush;
        CompositionBrush = nullptr;
    }
}

然後可以使用上述筆刷，就像任何其他 XAML 筆刷類型一樣來繪製 UIElements，例如：

針對 C++/WinRT，也請新增 #include "BackdropBlurBrush.h" 至 MainPage.h 。

<Ellipse Width="100" Height="100">
    <Ellipse.Fill>
        <local:BackdropBlurBrush BlurAmount="10" />
    </Ellipse.Fill>
</Ellipse>

備註

您可以使用 XamlCompositionBrushBase 來建立自訂筆刷。

例如，它可以用來建立一個筆刷，以使用CompositionEffectBrush將效果套用至 XAML UIElements，或使用SceneLightingEffect控制由 XamlLight所亮起之元素的反射屬性，或鏈結在一起的整個一系列效果，以產生更複雜的專案。

建立筆刷時，通常會延遲建立 CompositionBrush 和任何相關資源，直到使用筆刷為止。第一次在螢幕上使用筆刷來繪製元素時，會呼叫 OnConnected 方法，因此您可以覆寫 OnConnected ，只在需要時安全地建立資源。這表示您可以在 ResourceDictionary 中建立筆刷的實例，然後從 UI 定義的其他部分參考該筆刷資源，並只在實際使用筆刷時支付建立組合資源的成本。

當組合資源不再使用時，也是一個很好的做法。當筆刷實例不再使用在螢幕上的任何位置時，就會呼叫 OnDisconnected 方法，因此您可以覆寫 OnDisconnected 以安全地處置資源。如果在中斷連線之後再次使用筆刷，則會再次呼叫 OnConnected 。

建構函式

XamlCompositionBrushBase()

提供 XamlCompositionBrushBase 衍生類別的基類初始化行為。

屬性

CompositionBrush	取得或設定這個 XAML 筆刷所使用的 CompositionBrush 。
Dispatcher	取得這個物件相關聯的 CoreDispatcher 。 CoreDispatcher代表可在 UI 執行緒上存取DependencyObject的功能，即使程式碼是由非 UI 執行緒起始也一樣。 (繼承來源 DependencyObject)
FallbackColor	當 CompositionBrush 無法轉譯時，用於轉譯的色彩。
FallbackColorProperty	識別 FallbackColor 相依性屬性。
Opacity	取得或設定 Brush的不透明度。 (繼承來源 Brush)
RelativeTransform	取得或設定使用相對座標套用到筆刷的轉換。 (繼承來源 Brush)
Transform	取得或設定套用到筆刷的轉換。 (繼承來源 Brush)

方法

ClearValue(DependencyProperty)	清除相依性屬性的本機值。 (繼承來源 DependencyObject)
GetAnimationBaseValue(DependencyProperty)	傳回為相依性屬性建立的任何基底值，如果動畫未使用中，則適用此屬性。 (繼承來源 DependencyObject)
GetValue(DependencyProperty)	從 DependencyObject傳回相依性屬性的目前有效值。 (繼承來源 DependencyObject)
OnConnected()	第一次在螢幕上使用筆刷來繪製專案時叫用。在衍生類別中實作時，您可以建立 CompositionBrush 實例，並藉由設定 CompositionBrush 屬性提供給架構。當筆刷不再用來繪製任何元素時，將會呼叫OnDisconnected。
OnDisconnected()	當筆刷不再用來繪製任何專案時叫用。在衍生類別中實作時，您可以安全地處置撰寫筆刷和其他組合資源。如果筆刷稍後用來在中斷連線之後繪製任何元素，則會再次呼叫OnConnected。
PopulatePropertyInfo(String, AnimationPropertyInfo)	定義可以產生動畫效果的屬性。 (繼承來源 Brush)
PopulatePropertyInfoOverride(String, AnimationPropertyInfo)	在衍生類別中覆寫時，定義可以產生動畫效果的屬性。 (繼承來源 Brush)
ReadLocalValue(DependencyProperty)	如果已設定本機值，則傳回相依性屬性的本機值。 (繼承來源 DependencyObject)
RegisterPropertyChangedCallback(DependencyProperty, DependencyPropertyChangedCallback)	註冊通知函式，以接聽此DependencyObject實例上特定DependencyProperty的變更。 (繼承來源 DependencyObject)
SetValue(DependencyProperty, Object)	設定 DependencyObject上相依性屬性的本機值。 (繼承來源 DependencyObject)
UnregisterPropertyChangedCallback(DependencyProperty, Int64)	取消先前透過呼叫 RegisterPropertyChangedCallback註冊的變更通知。 (繼承來源 DependencyObject)

適用於

XamlCompositionBrushBase 類別

定義

Windows 需求

範例

備註

建構函式

屬性

方法

適用於

另請參閱

意見反應

意見反應

其他資源