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XamlCompositionBrushBase 類別

定義

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
屬性

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"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 CoreDispatcherCoreDispatcher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

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)

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

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