Performance drops as window size increases

Bug Report Template

ScottPlot Version: 4.1.15

Operating System: Windows 10 x64

Application Type: WinForms

Bug Description: I have a Plot containing 4 SignalPlots each with <200,000 data points. The FormsPlot is docked to fill the window, as the window size (and therefore the FormsPlot size) is increased the rendering becomes slower. When the FormsPlot is 1238x498 the render time is ~60ms, when resized to 3822x1840 render time goes up to ~700ms. I assume this isn’t normal. Your 5 million point demo doesn’t seem to exhibit this behaviour.

Reproducing: Simple example below, but without the 18mb of data (in serialised xml format), I can upload this if it helps

// simple winform with FormsPlot object docked to fill window
        double[][] data = new double[4][];
        string[] yLabels = new string[] { "-2000", "", "0", "", "2000", "-2000", "", "0", "", "+2000", "-200", "", "0", "", "+200", "-200", "", "0", "", "+200" };
        double[] yLabelPos = new double[] { -200, -100, 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 };

        private void Form1_Load(object sender, EventArgs e) {
            System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(data.GetType());
            System.IO.TextReader reader = new System.IO.StreamReader(@"c:\temp\data.xml");
            data = (double[][])x.Deserialize(reader);

            for (int i = 0; i < data[0].Length; i++) {
                data[2][i] /= 10;
                data[3][i] /= 10;
            }

            SignalPlot sp = formsPlot1.Plot.AddSignal(data[0], 200);
            sp.OffsetY = 1500;
            sp = formsPlot1.Plot.AddSignal(data[1], 200);
            sp.OffsetY = 1000;
            sp = formsPlot1.Plot.AddSignal(data[2], 200);
            sp.OffsetY = 500;
            sp = formsPlot1.Plot.AddSignal(data[3], 200);
            sp.OffsetY = 0;
            formsPlot1.Plot.YTicks(yLabelPos, yLabels);
            formsPlot1.Plot.SetAxisLimitsY(-300, 1800);
        }

[raburton]

Ok, thanks for looking in to this for me. I’ll probably start with the graph zoomed in instead of fully zoomed out then. If people want to zoom all the way out they’ll probably expect it to slow down, rather than starting slow and getting faster as they zoom in. I’ll try the render queue option as well.

[swharden]

Activating the render queue will render in another thread and not block the UI thread while interacting with the mouse. It probably won’t increase the framerate, but it may make your application feel smoother. Worth a try!

formsPlot1.Configuration.UseRenderQueue = true;