.NET (Core and Framework)

NetQuestions wrote:

Was it because of size.

myForm.Controls.Add(myPanel);

private void AddNewData() {
	int w=plot.Width;
	int h=plot.Height;
	int x=dataCount%w;
	bmg.DrawLine(Pens.Yellow, x, 0, x, h);
	int y=(int)(h*(0.5+0.45*Math.Sin(dataCount*0.07)));
	if (oldy<0) oldy=y;
	bmg.DrawLine(Pens.Black, x, oldy, x, y);
	oldy=y;
        dataCount++;
}

            g = pe.Graphics;

            int H = myBitmap.Height;
            int W = myBitmap.Width;

            Rectangle rect = new Rectangle(0, 0, W, H);
            myBitmapData = myBitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, myBitmap.PixelFormat);

            // Get the address of the first line.
            IntPtr ptr = myBitmapData.Scan0;

            // Declare an array to hold the bytes of the bitmap.
            int bytes = myBitmapData.Stride * H;
            byte[] rgbValues = new byte[bytes];

            // Copy the RGB values into the array.
            System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);

            // Shift the first N-1 columns one pixel to the right
            for (int ii = 0; ii < H; ii++)
                for (int jj = (ii + 1) * (3 * W) - 1; jj > (ii * W * 3) + 3; jj -= 3)
                {
                    rgbValues[jj] = rgbValues[jj-3];
                    rgbValues[jj-1] = rgbValues[jj-4];
                    rgbValues[jj-2] = rgbValues[jj-5];
                }

            // fill in some random data in the first column
            int offset = W * 3;
            for (int counter = 0; counter < H; counter += 1)
            {
                rgbValues[counter * offset] = (byte)rnd.Next(255);
                rgbValues[counter * offset + 1] = (byte)rnd.Next(255);
                rgbValues[counter * offset + 2] = (byte)rnd.Next(255);
            }

            // Copy the RGB values back to the bitmap
            System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);

            // Unlock the bits.
            myBitmap.UnlockBits(myBitmapData);
            myPanel.Location = new Point(XREF, YREF);
            myPanel.Width = myBitmap.Width;
            myPanel.Height = myBitmap.Height;
            myPanel.BackgroundImage = myBitmap;
            this.Controls.Add(myPanel);

My panel class (read that double buffering with a panel should be done like this):

   public class DoubleBufferPanel : Panel
        {
            public DoubleBufferPanel()
            {
                // Set the value of the double-buffering style bits to true.
                this.SetStyle(ControlStyles.DoubleBuffer |
                ControlStyles.UserPaint |
                ControlStyles.AllPaintingInWmPaint,
                true);
                this.UpdateStyles();
            }
        }

this.Controls.Add(myPanel);

myPanel.BackgroundImage = myBitmap;

// Copy the RGB values into the array

// some data members
private Bitmap bmPlot;
private int dataCount;
private BackgroundWorker bgw;
private bool running;
private int oldy=-1;
private Graphics bmg;

// the paint handler
private void plotter(object sender, PaintEventArgs e) {
	if (bmPlot!=null) {
		Graphics g=e.Graphics;
		int w=plot.Width;
		int h=plot.Height;
		int x=dataCount%w;
		g.DrawImage(bmPlot, new Rectangle(0, 0, w-x, h), new Rectangle(x, 0, w-x, h), GraphicsUnit.Pixel);
		g.DrawImage(bmPlot, new Rectangle(w-x, 0, x, h), new Rectangle(0, 0, x, h), GraphicsUnit.Pixel);
	}
}

// the button that causes things to start plotting
private void btnStart_Click(object sender, EventArgs e) {
	log("btnStart_Click");
	btnStop.Enabled=true;
	btnStart.Enabled=false;
	running=true;
	dataCount=0;
	oldy=-1;
	int w=plot.Width;
	int h=plot.Height;
	bmPlot=new Bitmap(w, h);
	bmg=Graphics.FromImage(bmPlot);
	bmg.FillRectangle(Brushes.Yellow, 0, 0, w, h);
	plot.Refresh();
	bgw=new BackgroundWorker();
	bgw.DoWork+=worker;
	bgw.ProgressChanged+=reporter;
	bgw.WorkerReportsProgress=true;
	log("starting bgw");
	bgw.RunWorkerAsync();
}

private void worker(object sender, object e) {
	while (running) {
		AddNewData();
		bgw.ReportProgress(0);
		Thread.Sleep(30);
	}
}

private void reporter(object sender, object e) {
	log("reporter");
	plot.Invalidate();
}

private void AddNewData() {
	int w=plot.Width;
	int h=plot.Height;
	int x=dataCount%plot.Width;
	bmg.DrawLine(Pens.Yellow, x, 0, x, h);
	int y=(int)(h*(0.5+0.45*Math.Sin(dataCount*0.07)));
	if (oldy<0) oldy=y;
	bmg.DrawLine(Pens.Black, x, oldy, x, y);
	oldy=y;
	dataCount++;
}

Panel oldPlot=plot;
plot=new DoubleBufferedPanel();
plot.Bounds=oldPlot.Bounds;
Controls.Remove(oldPlot);
Controls.Add(plot);
plot.Paint+=plotter;