Jim.
Extent and ratio of the width and height are very important for the PDF printing in your situation. DrawingArea is a specific screen area which used for filling the image to. There might be something setting issue in your code.
Please look at the sample code below. If you still can not solve the problem, could you paste your code here so that we can debug it?
PdfDocument doc = new PdfDocument();
PdfPage page = doc.AddPage();
page.Width = 800;
page.Height = 800;
double resolution = Math.Max(Map1.CurrentExtent.Width / Map1.Width.Value, Map1.CurrentExtent.Height / Map1.Height.Value);
RectangleShape newDrawingExtent = new RectangleShape(Map1.CurrentExtent.UpperLeftPoint.X, Map1.CurrentExtent.UpperLeftPoint.Y, Map1.CurrentExtent.UpperLeftPoint.X + 800 * resolution, Map1.CurrentExtent.UpperLeftPoint.Y - 800 * resolution);
PdfGeoCanvas canvas = new PdfGeoCanvas();
canvas.BeginDrawing(page, newDrawingExtent, GeographyUnit.DecimalDegree);
worldLayer.Open();
worldLayer.Draw(canvas, new Collection<SimpleCandidate>() { });
worldLayer.Close();
canvas.EndDrawing();
canvas.DrawingArea = new System.Drawing.Rectangle(0, 0, 400, 400);
canvas.BeginDrawing(page, Map1.CurrentExtent, GeographyUnit.DecimalDegree);
rasterLayer.Open();
rasterLayer.Draw(canvas, new Collection<SimpleCandidate>() { });
rasterLayer.Close();
canvas.EndDrawing();
doc.Save("c:\\1.pdf");
Thanks
James