wpf - 如何将 ViewBox 转换为 ImageSource？

Question

我正在使用 Viewbox创建一组我将动态绑定(bind)到 WPF View 的图标。

我正在绑定(bind)到资源名称并使用 Converter将资源名称转换为 ImageSource .

如果资源是 Path，我知道该怎么做，但是如何使用 Viewbox ?

如果资源是 Path，这就是我转换资源名称的方式。 , 到 ImageSource :

public class ResourceNameToImageSourceConverter : BaseValueConverter {
    protected override ImageSource Convert(string value, System.Globalization.CultureInfo culture) {
        var resource = new ResourceDictionary();
        resource.Source = new Uri("pack://application:,,,/MyAssembly;component/MyResourceFolder/ImageResources.xaml", UriKind.Absolute);
        var path = resource[value] as Path;
        if (path != null) {
            var geometry = path.Data;
            var geometryDrawing = new GeometryDrawing();
            geometryDrawing.Geometry = geometry;
            var drawingImage = new DrawingImage(geometryDrawing);


        geometryDrawing.Brush = path.Fill;
        geometryDrawing.Pen = new Pen();

        drawingImage.Freeze();
        return drawingImage;
    } else {
        return null;
    }
}

}
And this is what the Viewbox declaration looks like.


 
<Viewbox>
    <Viewbox>
      <Grid>
        <Path>
        ...
        </Path>
        <Path>
        ...
        </Path>
        <Path>
        ...
        </Path>
        <Rectangle>
        ...
        </Rectangle>
      </Grid>
    </Viewbox>
</Viewbox>
			            

Answer 1

Viewbox 是一个视觉元素，因此您需要手动将其“渲染”为位图。这个blog帖子显示了这是如何完成的，但相关代码是:

private static BitmapSource CaptureScreen(Visual target, double dpiX, double dpiY) {
    if (target == null)
        return null;

    Rect bounds = VisualTreeHelper.GetDescendantBounds(target);
    RenderTargetBitmap rtb = new RenderTargetBitmap((int)(bounds.Width * dpiX / 96.0),
                                                (int)(bounds.Height * dpiY / 96.0),
                                                dpiX,
                                                dpiY,
                                                PixelFormats.Pbgra32);
    DrawingVisual dv = new DrawingVisual();
    using (DrawingContext ctx = dv.RenderOpen()) {
        VisualBrush vb = new VisualBrush(target);
        ctx.DrawRectangle(vb, null, new Rect(new Point(), bounds.Size));
    }

    rtb.Render(dv);
    return rtb;
}