public HeatMapLayer()
{
heatPoints = new HeatPointCollection();
heatPoints.CollectionChanged += new NotifyCollectionChangedEventHandler(heatPoints_CollectionChanged);
fullBounds = Rectangle2D.Empty;
//设置GradientStops的默认值
GradientStopCollection stops = new GradientStopCollection();
stops.Add(new GradientStop() { Color = Color.FromArgb(0, 0, 0, 0), Offset = 0 });
stops.Add(new GradientStop() { Color = new Color() { A = 0xff, R = 0xff, G = 0x42, B = 0x00 }, Offset = 0.75 });
stops.Add(new GradientStop() { Color = new Color() { A = 0xff, R = 0xff, G = 0xff, B = 0x00 }, Offset = .5 });
stops.Add(new GradientStop() { Color = new Color() { A = 0xff, R = 0x1a, G = 0xa4, B = 0x03 }, Offset = .25 });
GradientStops = stops;
//初始化后台线程
worker = new BackgroundWorker { WorkerReportsProgress = true, WorkerSupportsCancellation = true };
worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
worker.DoWork += new DoWorkEventHandler(worker_DoWork);
}