如何在OxyPlot中画ROI获取数据

在OxyPlot中画ROI获取数据的步骤如下：

1. 添加一个Plot控件到你的窗体中，用于显示绘图结果。

2. 在窗体的代码文件中，添加以下引用：

using OxyPlot;
using OxyPlot.Annotations;
using OxyPlot.Axes;
using OxyPlot.Series;

3. 创建一个PlotModel对象，并添加一个LineSeries对象用于绘制数据。

// Create the plot model
var plotModel = new PlotModel();

// Create the X and Y axes
var xAxis = new LinearAxis { Position = AxisPosition.Bottom };
var yAxis = new LinearAxis { Position = AxisPosition.Left };

// Add the axes to the plot model
plotModel.Axes.Add(xAxis);
plotModel.Axes.Add(yAxis);

// Create the line series
var lineSeries = new LineSeries();

// Add the line series to the plot model
plotModel.Series.Add(lineSeries);

4. 添加一个RectangleAnnotation对象用于绘制ROI。

// Create the rectangle annotation
var rectangleAnnotation = new RectangleAnnotation();
rectangleAnnotation.Fill = OxyColors.LightBlue.ChangeAlpha(50);
rectangleAnnotation.Stroke = OxyColors.Blue;
rectangleAnnotation.StrokeThickness = 2;

// Add the rectangle annotation to the plot model
plotModel.Annotations.Add(rectangleAnnotation);

5. 在窗体的MouseDown事件中，设置RectangleAnnotation对象的起始坐标。

private void plot1_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        // Set the start point of the rectangle annotation
        var plotPosition = plot1.ActualModel.InverseTransform(e.Location);
        var start = new ScreenPoint(plotPosition.X, plotPosition.Y);
        rectangleAnnotation.Minimum = xAxis.InverseTransform(start.X);
        rectangleAnnotation.Maximum = xAxis.InverseTransform(start.X);
        rectangleAnnotation.MinimumY = yAxis.InverseTransform(start.Y);
        rectangleAnnotation.MaximumY = yAxis.InverseTransform(start.Y);
    }
}

6. 在窗体的MouseMove事件中，更新RectangleAnnotation对象的大小。

private void plot1_MouseMove(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        // Set the end point of the rectangle annotation
        var plotPosition = plot1.ActualModel.InverseTransform(e.Location);
        var end = new ScreenPoint(plotPosition.X, plotPosition.Y);
        rectangleAnnotation.Maximum = xAxis.InverseTransform(end.X);
        rectangleAnnotation.MaximumY = yAxis.InverseTransform(end.Y);
    }
}

7. 在窗体的MouseUp事件中，获取ROI范围内的数据。

private void plot1_MouseUp(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        // Get the data points within the rectangle annotation
        var minX = Math.Min(rectangleAnnotation.Minimum.Value, rectangleAnnotation.Maximum.Value);
        var maxX = Math.Max(rectangleAnnotation.Minimum.Value, rectangleAnnotation.Maximum.Value);
        var minY = Math.Min(rectangleAnnotation.MinimumY.Value, rectangleAnnotation.MaximumY.Value);
        var maxY = Math.Max(rectangleAnnotation.MinimumY.Value, rectangleAnnotation.MaximumY.Value);
        var dataPoints = lineSeries.Points.Where(p => p.X >= minX && p.X <= maxX && p.Y >= minY && p.Y <= maxY);

        // Do something with the data points
        foreach (var dataPoint in dataPoints)
        {
            // ...
        }
    }
}

这些代码将在鼠标按下、移动和释放事件中设置RectangleAnnotation对象的起始坐标和大小，并获取ROI范围内的数据点。你可以根据自己的需求来修改代码以实现更复杂的操作。