如何模糊 Windows 10 XAML 中的图像?

How do you blur an image in Windows 10 XAML?

我环顾了这个网站,但还没有找到在 XAML 中模糊图像的方法。我在 C# 中尝试了一些函数,但它们没有用。我想实现模糊背景图像,就像在 Audiocloud 应用程序 (https://store-images.s-microsoft.com/image/apps.28769.9007199266467874.da79334d-0f1c-4851-8e0b-7ee566918b20.0658cd96-487e-4e1f-a330-10fb030aaa22?w=443&h=788&q=60) 中一样。我将如何完成这项工作?

  1. 将 Microsoft Win2D.uwp NuGet 包添加到您的项目中。 (在解决方案资源管理器中右键单击您的项目 > "Manage NuGet packages...")
  2. 有这个例子XAML UI:

    <Grid>
        <Image x:Name="myBackground" Stretch="UniformToFill" />
        <Image x:Name="myImage" Width="360" Height="300" Source="Assets/test.png" Stretch="UniformToFill" ImageOpened="myImage_ImageOpened"/>
    </Grid>
    
  3. 在静态 class 中为 UIElement 创建扩展方法:

    static class Extension
    {
        public static async Task<IRandomAccessStream>
            RenderToRandomAccessStream(this UIElement element)
        {
            RenderTargetBitmap rtb = new RenderTargetBitmap();
            await rtb.RenderAsync(element);
    
            var pixelBuffer = await rtb.GetPixelsAsync();
            var pixels = pixelBuffer.ToArray();
            var displayInformation = DisplayInformation.GetForCurrentView();
    
            var stream = new InMemoryRandomAccessStream();
            var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
            encoder.SetPixelData(BitmapPixelFormat.Bgra8,
                                 BitmapAlphaMode.Premultiplied,
                                 (uint)rtb.PixelWidth,
                                 (uint)rtb.PixelHeight,
                                 displayInformation.RawDpiX,
                                 displayInformation.RawDpiY,
                                 pixels);
    
            await encoder.FlushAsync();
            stream.Seek(0);
    
            return stream;
        }
    }
    
  4. 使用它。例如在你的 public sealed partial class MainPage : Page:

    private async void BlurThisUI(UIElement sourceElement, Image outputImage)
    {
        using (var stream = await sourceElement.RenderToRandomAccessStream())
        {
            var device = new CanvasDevice();
            var bitmap = await CanvasBitmap.LoadAsync(device, stream);
    
            var renderer = new CanvasRenderTarget(device,
                                                  bitmap.SizeInPixels.Width,
                                                  bitmap.SizeInPixels.Height,
                                                  bitmap.Dpi);
    
            using (var ds = renderer.CreateDrawingSession())
            {
                var blur = new GaussianBlurEffect();
                blur.BlurAmount = 5.0f;
                blur.Source = bitmap;
                ds.DrawImage(blur);
            }
    
            stream.Seek(0);
            await renderer.SaveAsync(stream, CanvasBitmapFileFormat.Png);
    
            BitmapImage image = new BitmapImage();
            image.SetSource(stream);
            outputImage.Source = image;
        }
    }
    
  5. 调用它。在这个例子中,当图像被打开时(见上面的XAML:ImageOpened="myImage_ImageOpened"):

    private void myImage_ImageOpened(object sender, RoutedEventArgs e)
    {
        this.BlurThisUI(myImage, myBackground);
    }
    
  6. 感谢 Nikola Metulev this tutorial

备注

如您所见,您不仅可以使用它来模糊图像,还可以使用任何 UIElement(例如包含所有 UI 元素的网格,如按钮、复选框等)

全部使用

using System;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Graphics.Display;
using Windows.Graphics.Imaging;
using Windows.Storage.Streams;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using Microsoft.Graphics.Canvas;
using Microsoft.Graphics.Canvas.Effects;