[UWP]如何在UWP的irandomaccessstream中添加文本？

问题描述

这是我的功能记录ip camera。如何在我拥有的每个图像（_frameBuffer）中插入时间。当我完成记录后，我会收到一个视频，其中包含我添加到每张图片中的图片和时间。

public async void Record(byte[] _frameBuffer)
{
using (IRandomAccessStream stream = new InMemoryRandomAccessStream())
{
   await stream.WriteAsync(_frameBuffer.AsBuffer());
   stream.Seek(0);

   var decoder = await BitmapDecoder.CreateAsync(stream);
   PixelDataProvider dataProvider = await decoder.GetPixelDataAsync(
          BitmapPixelFormat.Bgra8,
          BitmapAlphaMode.Straight,
          new BitmapTransform { ScaledWidth = this.PixelWidth, ScaledHeight = this.PixelHeight },
          ExifOrientationMode.RespectExifOrientation,
          ColorManagementMode.ColorManageToSRgb);
    if (this.PictureWriter != null)
          PictureWriter?.AddFrame(dataProvider.DetachPixelData(), (int)this.PixelWidth, (int)this.PixelHeight);
    stream.Dispose();
}
}

我非常感谢所有人的帮助 我尝试过： 我找到了一个可以将文本插入图像的解决方案。但在我的情况下，我还没有找到解决方法。

private async void Button_Click(object sender, RoutedEventArgs e)
{
    var picker = new FileOpenPicker();
    picker.FileTypeFilter.Add(".png");
    picker.FileTypeFilter.Add(".jpg");
    picker.FileTypeFilter.Add(".jpeg");
    var sourceFile = await picker.PickSingleFileAsync();

    if (sourceFile == null) { return; }

    var device = CanvasDevice.GetSharedDevice();
    var image = default(CanvasBitmap);
    using (var s = await sourceFile.OpenReadAsync())
    {
        image = await CanvasBitmap.LoadAsync(device, s);
    }
    var offscreen = new CanvasRenderTarget(
        device, (float)image.Bounds.Width, (float)image.Bounds.Height, 96);

    using (var ds = offscreen.CreateDrawingSession())
    {
        ds.DrawImage(image, 0, 0);
        ds.DrawText("Hello world", 10, 10, Colors.Blue);
    }
    var displayInformation = DisplayInformation.GetForCurrentView();
    var savepicker = new FileSavePicker();
    savepicker.FileTypeChoices.Add("png", new List<string> { ".png" });
    var destFile = await savepicker.PickSaveFileAsync();

    using (var s = await destFile.OpenAsync(FileAccessMode.ReadWrite))
    {
        var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, s);
        encoder.SetPixelData(
            BitmapPixelFormat.Bgra8,
            BitmapAlphaMode.Ignore,
            (uint)offscreen.Size.Width,
            (uint)offscreen.Size.Height,
            displayInformation.LogicalDpi,
            displayInformation.LogicalDpi,
            offscreen.GetPixelBytes());
        await encoder.FlushAsync();
    }
}

推荐答案

这是我的功能记录ip camera。如何在我拥有的每个图像（_frameBuffer）中插入时间。当我完成记录时，我得到一个包含图像的视频和我添加到每个图像的时间。

public async void Record(byte[] _frameBuffer)
{
using (IRandomAccessStream stream = new InMemoryRandomAccessStream())
{
   await stream.WriteAsync(_frameBuffer.AsBuffer());
   stream.Seek(0);

   var decoder = await BitmapDecoder.CreateAsync(stream);
   PixelDataProvider dataProvider = await decoder.GetPixelDataAsync(
          BitmapPixelFormat.Bgra8,
          BitmapAlphaMode.Straight,
          new BitmapTransform { ScaledWidth = this.PixelWidth, ScaledHeight = this.PixelHeight },
          ExifOrientationMode.RespectExifOrientation,
          ColorManagementMode.ColorManageToSRgb);
    if (this.PictureWriter != null)
          PictureWriter?.AddFrame(dataProvider.DetachPixelData(), (int)this.PixelWidth, (int)this.PixelHeight);
    stream.Dispose();
}
}

我非常感谢所有人的帮助 我试过的： 我找到了一个可以解决的问题将文本插入图像。但就我而言，我还没有办法解决它。

private async void Button_Click(object sender, RoutedEventArgs e)
{
    var picker = new FileOpenPicker();
    picker.FileTypeFilter.Add(".png");
    picker.FileTypeFilter.Add(".jpg");
    picker.FileTypeFilter.Add(".jpeg");
    var sourceFile = await picker.PickSingleFileAsync();

    if (sourceFile == null) { return; }

    var device = CanvasDevice.GetSharedDevice();
    var image = default(CanvasBitmap);
    using (var s = await sourceFile.OpenReadAsync())
    {
        image = await CanvasBitmap.LoadAsync(device, s);
    }
    var offscreen = new CanvasRenderTarget(
        device, (float)image.Bounds.Width, (float)image.Bounds.Height, 96);

    using (var ds = offscreen.CreateDrawingSession())
    {
        ds.DrawImage(image, 0, 0);
        ds.DrawText("Hello world", 10, 10, Colors.Blue);
    }
    var displayInformation = DisplayInformation.GetForCurrentView();
    var savepicker = new FileSavePicker();
    savepicker.FileTypeChoices.Add("png", new List<string> { ".png" });
    var destFile = await savepicker.PickSaveFileAsync();

    using (var s = await destFile.OpenAsync(FileAccessMode.ReadWrite))
    {
        var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, s);
        encoder.SetPixelData(
            BitmapPixelFormat.Bgra8,
            BitmapAlphaMode.Ignore,
            (uint)offscreen.Size.Width,
            (uint)offscreen.Size.Height,
            displayInformation.LogicalDpi,
            displayInformation.LogicalDpi,
            offscreen.GetPixelBytes());
        await encoder.FlushAsync();
    }
}