保存UIElement的图像,使其比屏幕上显示的图像大

Question

我有一个图表,我正在向用户显示,我希望能够将图表作为图像导出到磁盘,以便他们可以在应用程序之外使用它(用于演示文稿或其他东西).

我已经设法使用PngBitmapEncoder和RenderTargetBitmap来获得基本的想法,但我得到的图像是小到可以使用的方式,我希望得到更大的图像.

我试图简单地增加我想要渲染的控件的高度和宽度,但是父级似乎可以直接控制渲染大小.从这里我试图在内存中复制UIElement但是然后渲染大小为(0,0)并且当我尝试使用方法来渲染它时,例如Measure()Arrange()和UpdateLayout()它们会抛出异常需要解耦父级来调用它们,但因为它在内存中而不是渲染,所以不应该是父级？

这一切都是使用Visiblox图表API完成的

这是我目前所拥有的,除了它不起作用:(

var width = 1600;
var height = 1200;

var newChart = new Chart { Width = width, Height = height, Title = chart.Title, XAxis = chart.XAxis, YAxis = chart.YAxis, Series = chart.Series};
Debug.WriteLine(newChart.RenderSize);
var size = new Size(width, height);
newChart.Measure(size);
newChart.Arrange(new Rect(size));
newChart.UpdateLayout();
Debug.WriteLine(newChart.RenderSize);

var rtb = new RenderTargetBitmap(width, height, 96, 96, PixelFormats.Pbgra32);
            rtb.Render(newChart);

var encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(rtb));

using (var stream = fileDialog.OpenFile())
   encoder.Save(stream);

我已经离得更近了,它现在将图形背景渲染为轴'等等,但不是实际绘制的线条.以下是更新的来源

public static void RenderChartToImage(Chart elementToRender, string filename)
{
    if (elementToRender == null)
        return;
    Debug.Write(elementToRender.RenderSize);
    var clone = new Chart();

    clone.Width = clone.Height = double.NaN;
    clone.HorizontalAlignment = HorizontalAlignment.Stretch;
    clone.VerticalAlignment = VerticalAlignment.Stretch;
    clone.Margin = new Thickness();

    clone.Title = elementToRender.Title;
    clone.XAxis = new DateTimeAxis();
    clone.YAxis = new LinearAxis() { Range = Range<double>)elementToRender.YAxis.Range};

    foreach (var series in elementToRender.Series)
    {
        var lineSeries = new LineSeries
                             {
                                 LineStroke = (series as LineSeries).LineStroke,
                                 DataSeries = series.DataSeries
                             };
        clone.Series.Add(lineSeries);
    }


    var size = new Size(1600, 1200);

    clone.Measure(size);
    clone.Arrange(new Rect(size));
    clone.UpdateLayout();

    Debug.Write(clone.RenderSize);

    var height = (int)clone.ActualHeight;
    var width = (int)clone.ActualWidth;

    var renderer = new RenderTargetBitmap(width, height, 96d, 96d, PixelFormats.Pbgra32);

    renderer.Render(clone);

    var pngEncoder = new PngBitmapEncoder();
    pngEncoder.Frames.Add(BitmapFrame.Create(renderer));

    using (var file = File.Create(filename))
    {
        pngEncoder.Save(file);
    }
}

所以我得到这样的东西:

虽然很大,但没有用,因为它没有任何图表.

Answer 1

http://www.visiblox.com/blog/2011/05/printing-visiblox-charts

我错过的要点是

InvalidationHandler.ForceImmediateInvalidate = true;

在内存中渲染图表之前进行设置，然后在完成后恢复它。从那里开始一切都很顺利:D