任何方式保存图像文件编程创建的UIElement？ [英] Any way to save an UIElement created programmatically in an image file?

问题描述

我想保存在一款Windows Phone 8.1（C＃）应用程序中的JPG / PNG / BMP图像编程方式创建的UIElement。

我使用使用方法RenderAsync（），但只适用于在XAML代码中创建用户界面元素的类RenderTargetBitmap。当我用它直接在C＃创建用户界面元素我有这样的例外：System.ArgumentException（值没有在预期的范围内）

我做错，还是这个类不允许的UIElement（S）的渲染程序创建的？有没有办法做到这一点在Windows Phone 8.1吗？ ！谢谢

下面是我使用的代码：

 私有静态异步无效RenderText（字符串文字，诠释的宽度，高度INT，INT字号，串imagename）
 {
 RenderTargetBitmap b =新RenderTargetBitmap（）; 
 
变种帆布=新的Grid（）; 
 
 canvas.Width =宽度; 
 canvas.Height =高度; 
 
 VAR背景=新的Canvas（）; 
 background.Height =宽度; 
 background.Width =高度; 
 
的SolidColorBrush背景色=新的SolidColorBrush（Colors.Red）; 
 background.Background =背景色; 
 
变种文本块=新的TextBlock（）; 
 textBlock.Text =文本; 
 textBlock.FontWeight = FontWeights.Bold; 
 textBlock.TextAlignment = TextAlignment.Left; 
 textBlock.Horizo​​ntalAlignment = Horizo​​ntalAlignment.Center; 
 textBlock.VerticalAlignment = VerticalAlignment.Stretch; 
 textBlock.Margin =新厚度（35）; 
 //textBlock.Width = b.PixelWidth  -  textBlock.Margin.Left * 2; 
 textBlock.TextWrapping = TextWrapping.Wrap; 
 textBlock.Foreground =新的SolidColorBrush（Colors.White）; //对瓷砖
 textBlock.FontSize =字号文本的颜色; 
 
 canvas.Children.Add（文字块）; 
 
等待b.RenderAsync（背景）; 
等待b.RenderAsync（画布）; 
 
 //获取像素
 
 VAR pixelBuffer =等待b.GetPixelsAsync（）; 
 
 
 //获取本地文件夹。 
 StorageFolder本地= Windows.Storage.ApplicationData.Current.LocalFolder; 
 
 //创建一个新的文件夹名称DataFolder。 
 VAR dataFolder =等待local.CreateFolderAsync（DataFolder，
 CreationCollisionOption.OpenIfExists）; 
 
 StorageFile文件=等待dataFolder.CreateFileAsync（imagename，CreationCollisionOption.ReplaceExisting）; 
 
 
 //使用编码图像磁盘上
选定的文件（VAR FILESTREAM =等待file.OpenStreamForWriteAsync（））
 {
 
变种编码=等待BitmapEncoder.CreateAsync（BitmapEncoder.PngEncoderId，fileStream.AsRandomAccessStream（））; 
 
 encoder.SetPixelData（
 BitmapPixelFormat.Bgra8，
 BitmapAlphaMode.Ignore，
（UINT）b.PixelWidth，
（UINT）b.PixelHeight， 
 DisplayInformation.GetForCurrentView（）LogicalDpi，
 DisplayInformation.GetForCurrentView（）LogicalDpi，
 pixelBuffer.ToArray（））。 
 
等待encoder.FlushAsync（）; 
} 
} 
  

解决方案

据不与XAML创建的元素，但这些只工作（如 MSDN说： ）在的VisualTree ：

渲染的快照的UIElement 可视化树以图像源。

所以，如果你比如添加元素到当前页面的方法将工作：

  LayoutRoot.Children.Add（画布）; 
  

I'm trying to save an UIElement created programmatically in a JPG/PNG/BMP image in a Windows Phone 8.1 (C#) application.

I'm using the class RenderTargetBitmap using the method RenderAsync() but it only works with UI elements created in the XAML code. When I use it on UI elements created directly in C# I have this exception: "System.ArgumentException (Value does not fall within the expected range.)"

Am I doing something wrong or this class doesn't allow rendering of UIElement(s) created programmatically? Is there any way to do this on Windows Phone 8.1? Thank you!

Here's the code I use:

        private static async void RenderText(string text, int width, int height, int fontsize, string imagename)
    {
        RenderTargetBitmap b = new RenderTargetBitmap();

        var canvas = new Grid();

        canvas.Width = width;
        canvas.Height = height;

        var background = new Canvas();
        background.Height = width;
        background.Width = height;

        SolidColorBrush backColor = new SolidColorBrush(Colors.Red);
        background.Background = backColor;

        var textBlock = new TextBlock();
        textBlock.Text = text;
        textBlock.FontWeight = FontWeights.Bold;
        textBlock.TextAlignment = TextAlignment.Left;
        textBlock.HorizontalAlignment = HorizontalAlignment.Center;
        textBlock.VerticalAlignment = VerticalAlignment.Stretch;
        textBlock.Margin = new Thickness(35);
        //textBlock.Width = b.PixelWidth - textBlock.Margin.Left * 2;
        textBlock.TextWrapping = TextWrapping.Wrap;
        textBlock.Foreground = new SolidColorBrush(Colors.White); //color of the text on the Tile
        textBlock.FontSize = fontsize;

        canvas.Children.Add(textBlock);

        await b.RenderAsync(background);
        await b.RenderAsync(canvas);

        // Get the pixels

        var pixelBuffer = await b.GetPixelsAsync();


        // Get the local folder.
        StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;

        // Create a new folder name DataFolder.
        var dataFolder = await local.CreateFolderAsync("DataFolder",
            CreationCollisionOption.OpenIfExists);

        StorageFile file = await dataFolder.CreateFileAsync(imagename, CreationCollisionOption.ReplaceExisting);


        // Encode the image to the selected file on disk
        using (var fileStream = await file.OpenStreamForWriteAsync())
        {

            var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, fileStream.AsRandomAccessStream());

            encoder.SetPixelData(
                BitmapPixelFormat.Bgra8,
                BitmapAlphaMode.Ignore,
                (uint)b.PixelWidth,
                (uint)b.PixelHeight,
                DisplayInformation.GetForCurrentView().LogicalDpi,
                DisplayInformation.GetForCurrentView().LogicalDpi,
                pixelBuffer.ToArray());

            await encoder.FlushAsync();
        }
    }

解决方案

It is not working only with elements created in XAML but with these that (as MSDN says) are in VisualTree:

Renders a snapshot of a UIElement visual tree to an image source.

So your method will work if you add your elements for example to your current Page:

LayoutRoot.Children.Add(canvas);

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