背水一战 Windows 10 (65) - 控件（WebView）: 对 WebView 中的内容截图, 通过 Share Contract 分享 WebView 中的被选中的内容

<Page

    x:Class="Windows10.Controls.WebViewDemo.WebViewDemo5"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="using:Windows10.Controls.WebViewDemo"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d">

    <Grid Background="Transparent">

        <StackPanel Margin="10 0 10 10">

            <Button Name="btnCapture" Content="对此 WebView 中的当前内容截图" Click="btnCapture_Click" Margin="5" />

            <WebView Name="webView" Width="400" Height="300" Source="http://webabcd.cnblogs.com/" HorizontalAlignment="Left" Margin="5" />

            <StackPanel Margin="5" Orientation="Horizontal">

                <Image Name="imageOriginal" Width="400" Height="300" HorizontalAlignment="Left" />

                <Image Name="imageThumbnail" Width="400" Height="300" HorizontalAlignment="Left" Margin="10 0 0 0" />

            </StackPanel>

        </StackPanel>

    </Grid>

</Page>

/*

 * WebView - 内嵌浏览器控件（继承自 FrameworkElement, 请参见 /Controls/BaseControl/FrameworkElementDemo/）

 *     CapturePreviewToStreamAsync() - 对 WebView 当前显示的内容截图，并将图片写入指定的流

 *

 *

 * 本例用于演示如何对 WebView 中的内容截图

 */

using System;

using System.Runtime.InteropServices.WindowsRuntime;

using System.Threading.Tasks;

using Windows.Graphics.Imaging;

using Windows.Storage.Streams;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

using Windows.UI.Xaml.Media.Imaging;

namespace Windows10.Controls.WebViewDemo

{

    public sealed partial class WebViewDemo5 : Page

    {

        public WebViewDemo5()

        {

            this.InitializeComponent();

        }

        private async void btnCapture_Click(object sender, RoutedEventArgs e)

        {

            // 对 WebView 中的内容截图，并将原始图像数据放入内存流

            InMemoryRandomAccessStream ms = new InMemoryRandomAccessStream();

            await webView.CapturePreviewToStreamAsync(ms);

            // 显示原始截图

            BitmapImage bitmapImage = new BitmapImage();

            bitmapImage.SetSource(ms);

            imageOriginal.Source = bitmapImage;

            // 定义缩略图的大小（最长边定义为 180）

            int longlength = , width = , height = ;

            double srcwidth = webView.ActualWidth, srcheight = webView.ActualHeight;

            double factor = srcwidth / srcheight;

            if (factor < )

            {

                height = longlength;

                width = (int)(longlength * factor);

            }

            else

            {

                width = longlength;

                height = (int)(longlength / factor);

            }

            // 显示原始截图的缩略图

            BitmapSource thumbnail = await resize(width, height, ms);

            imageThumbnail.Source = thumbnail;

        }

        // 将指定的图片修改为指定的大小，并返回修改后的图片

        private async Task<BitmapSource> resize(int width, int height, IRandomAccessStream source)

        {

            WriteableBitmap thumbnail = new WriteableBitmap(width, height);

            BitmapDecoder decoder = await BitmapDecoder.CreateAsync(source);

            BitmapTransform transform = new BitmapTransform();

            transform.ScaledHeight = (uint)height;

            transform.ScaledWidth = (uint)width;

            PixelDataProvider pixelData = await decoder.GetPixelDataAsync(

                BitmapPixelFormat.Bgra8,

                BitmapAlphaMode.Straight,

                transform,

                ExifOrientationMode.RespectExifOrientation,

                ColorManagementMode.DoNotColorManage);

            pixelData.DetachPixelData().CopyTo(thumbnail.PixelBuffer);

            return thumbnail;

        }

    }

}

<Page

    x:Class="Windows10.Controls.WebViewDemo.WebViewDemo6"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="using:Windows10.Controls.WebViewDemo"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d">

    <Grid Background="Transparent">

        <StackPanel Margin="10 0 10 10">

            <Button Name="btnShare" Content="通过 Share Contract 分享 WebView 中的被选中的内容（如果没有选中任何内容，则分享网页地址）" Click="btnShare_Click" Margin="5" />

            <WebView Name="webView" Width="400" Height="300" Source="http://webabcd.cnblogs.com/" HorizontalAlignment="Left" Margin="5" />

        </StackPanel>

    </Grid>

</Page>

/*

 * WebView - 内嵌浏览器控件（继承自 FrameworkElement, 请参见 /Controls/BaseControl/FrameworkElementDemo/）

 *     CaptureSelectedContentToDataPackageAsync() - 将选中的内容转换为 DataPackage 对象

 *     DataRequested - 分享操作开始时触发的事件（事件参数 DataRequestedEventArgs）

 *

 * DataRequestedEventArgs

 *     GetDeferral() - 获取异步操作对象，同时开始异步操作，之后通过 Complete() 通知完成异步操作

 *

 *

 * 本例用于演示如何通过 Share Contract 分享 WebView 中的被选中的内容（如果没有选中任何内容，则分享网页地址）

 */

using System;

using Windows.ApplicationModel.DataTransfer;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

namespace Windows10.Controls.WebViewDemo

{

    public sealed partial class WebViewDemo6 : Page

    {

        private DataTransferManager _dataTransferManager;

        public WebViewDemo6()

        {

            this.InitializeComponent();

        }

        private void btnShare_Click(object sender, RoutedEventArgs e)

        {

            _dataTransferManager = DataTransferManager.GetForCurrentView();

            _dataTransferManager.DataRequested += _dataTransferManager_DataRequested;

            DataTransferManager.ShowShareUI();

        }

        // 分享 WebView 中的被选中的内容

        async void _dataTransferManager_DataRequested(DataTransferManager sender, DataRequestedEventArgs args)

        {

            DataRequest request = args.Request;

            DataRequestDeferral deferral = args.Request.GetDeferral();

            // 如果 dataPackage 是 null 的话，则说明用户没有选择任何内容

            DataPackage dataPackage = await webView.CaptureSelectedContentToDataPackageAsync();

            // 用于判断用户是否选中了分享内容

            bool hasSelection = false;

            try

            {

                hasSelection = (dataPackage != null) && (dataPackage.GetView().AvailableFormats.Count > );

            }

            catch (Exception ex)

            {

                switch (ex.HResult)

                {

                    // 无法为选中的内容生成 data package

                    case unchecked((int)0x80070490):

                        hasSelection = false;

                        break;

                    default:

                        throw;

                }

            }

            if (hasSelection)

            {

                dataPackage.Properties.Title = "Title（hasSelection）";

            }

            else

            {

                // 用户没有选择任何内容的话，则分享网页地址

                dataPackage = new DataPackage();

                dataPackage.SetWebLink(webView.Source);

                dataPackage.Properties.Title = "Title";

            }

            dataPackage.Properties.Description = "Description";

            request.Data = dataPackage;

            _dataTransferManager.DataRequested -= _dataTransferManager_DataRequested;

            deferral.Complete();

        }

    }

}