private void GraphMain_PaintSurface(object sender, SkiaSharp.Views.Desktop.SKPaintSurfaceEventArgs e) { MainSurface = e.Surface; MainCanvas = MainSurface.Canvas; if (refresh) { MainCanvas.Clear(SKColors.Black); refresh = false; } // draw eraser MainCanvas.DrawRect(currentX, 0, 40, graphMain.CanvasSize.Height, ErasePaint); if (ClearFlag) { //MainCanvas.Clear(SKColors.Transparent); ClearFlag = false; if (displayArray1 != null && displayArray1.Length > 0) { MainCanvas.DrawPoints(PointMode2, displayArray1, GraphPaint1); } } else { if (displayArray1 != null && displayArray1.Length > 0) { MainCanvas.DrawPoints(PointMode1, displayArray1, GraphPaint1); } } }