XAML 主要 window 上的视频绘图？

Question

我在 WPF 中有以下使用 VideoDrawing 对象播放视频文件的简单示例 - 这是后面的代码：

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        MediaTimeline timeline = new MediaTimeline(new Uri(@"c:\test\RedRock-uhd-h264.mp4", UriKind.Absolute));
        timeline.RepeatBehavior = RepeatBehavior.Forever;
        MediaClock clock = timeline.CreateClock();
        MediaPlayer player = new MediaPlayer();
        player.Clock = clock;
        VideoDrawing drawing = new VideoDrawing();

        drawing.Rect = new Rect(0, 0, 820, 600);    //<--video size is 620 x 400 same as XAML MainWindow size
        drawing.Rect = new Rect(0, 0, 420, 280);    //<--video size is 620 x 400 same as XAML MainWindow size
        drawing.Rect = new Rect(0, 0, 220, 80);     //<--video size is 620 x 400 same as XAML MainWindow size
        drawing.Rect = new Rect(0, 0, 1, 1);        //<--video size is 620 x 400 same as XAML MainWindow size
        drawing.Rect = new Rect(0, 0, 0, 0);        //<--video does not show
        //drawing.Rect = new Rect(0, 0, 0, 0);      //<--video does not show

        drawing.Player = player;

        DrawingBrush brush = new DrawingBrush(drawing);
        this.Background = brush;            
    }
}

这里是 XAML:

<Window x:Class="MyMediaPlayer.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MediaPlayer in WPF" Width="620" Height="400" 
    WindowStyle="None"
    ShowInTaskbar="True"
    AllowsTransparency="True"
    Background="Transparent"
    WindowStartupLocation="Manual"
    Left="0"
    Top="0">

</Window>

查看上面的行“drawing.Rect = new Rect(…) 并注意注释 - 无论我将 Rect 设置为多大 - 视频始终以 [=21= 的大小播放] MainWindow 大小 (620, 400)，但是我必须至少设置一些 Rect 大小我不能将它设置为 0 或将其注释掉。看起来视频应该以设置的 Rect 大小播放，除非它更大比 XAML MainWindow 还大？我不明白我在做什么，为什么视频不能播放到 Rect 的大小？

Answer 1

将拉伸模式设置为None:

brush.Stretch = Stretch.None;

问题当然是您现在无法设置播放器周围区域的颜色。如果你想控制它，那么你必须切换到 VisualBrush 并改用 MediaElement：

// create a grid and bind it to the parent window's size
var grid = new Grid { Background = Brushes.CornflowerBlue };    // <- sets background color
grid.SetBinding(WidthProperty, new Binding
{
    RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(Window), 1),
    Path = new PropertyPath("ActualWidth"),
    Mode = BindingMode.OneWay,
    UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
});
grid.SetBinding(HeightProperty, new Binding
{
    RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(Window), 1),
    Path = new PropertyPath("ActualHeight"),
    Mode = BindingMode.OneWay,
    UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
});

// add the media player
grid.Children.Add(new MediaElement
{
    Source = new Uri("yourvideo.mp4", UriKind.RelativeOrAbsolute),
    LoadedBehavior = MediaState.Play,
    Stretch = Stretch.Fill,
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Center,
    Width = 640,    // <-- video size
    Height = 480
});

// wrap it all up in a visual brush
this.Background = new VisualBrush { Visual = grid };

XAML 主要 window 上的视频绘图？

VideoDrawing on XAML main window?

c#

wpf

media-player