/// <summary>
/// Generate a bitmap showing an overhead view of the gps waypoints
/// </summary>
/// <param name="width"></param>
/// <returns></returns>
private Stream GenerateTop(int width)
{
MemoryStream memory = null;
int height = width * 3 / 4;
using (Bitmap bmp = new Bitmap(width, height))
{
using (Graphics g = Graphics.FromImage(bmp))
{
g.Clear(Color.LightGray);
g.DrawRectangle(Pens.White, new Rectangle(-1, -1, 3, 3));
if (_state.History == null || _state.History.Count < 1)
{
g.DrawString("No Data - check 'Capture History' box to see the track", new Font(FontFamily.GenericSansSerif, 16, GraphicsUnit.Pixel), Brushes.Red, new Point(10, 10));
}
else // plot a simple map from the Gps waypoints
{
double minLongitude = 9999.0, minLatitude = 9999.0, minAltitude = 9999999.0;
double maxLongitude = -9999.0, maxLatitude = -9999.0, maxAltitude = -9999999.0;
foreach (EarthCoordinates ec in _state.History)
{
minLongitude = Math.Min(minLongitude, ec.Longitude);
minLatitude = Math.Min(minLatitude, ec.Latitude);
minAltitude = Math.Min(minAltitude, ec.AltitudeMeters);
maxLongitude = Math.Max(maxLongitude, ec.Longitude);
maxLatitude = Math.Max(maxLatitude, ec.Latitude);
maxAltitude = Math.Max(maxAltitude, ec.AltitudeMeters);
}
if (minLongitude < 0)
{
double hold = minLongitude;
minLongitude = maxLongitude;
maxLongitude = hold;
}
EarthCoordinates start = new EarthCoordinates(minLatitude, minLongitude, minAltitude);
EarthCoordinates end = new EarthCoordinates(maxLatitude, maxLongitude, maxAltitude);
Point3 box = end.OffsetFromStart(start);
double scale = Math.Max(box.X / (double)width, box.Y / (double)height);
Point lastPoint = Point.Empty;
Point currentPoint;
foreach (EarthCoordinates ec in _state.History)
{
box = ec.OffsetFromStart(start);
currentPoint = new Point(width - (int)(box.Y / scale) - 10, height - (int)(box.X / scale) - 10);
// Draw the point.
int dop = (int)Math.Truncate(ec.HorizontalDilutionOfPrecision);
Rectangle r = new Rectangle(currentPoint.X - dop, currentPoint.Y - dop, dop * 2, dop * 2);
g.FillEllipse(Brushes.Azure, r);
g.DrawEllipse(Pens.Yellow, r);
if (lastPoint == Point.Empty)
g.DrawString("Start", new Font(FontFamily.GenericSansSerif, 16, GraphicsUnit.Pixel), Brushes.Green, currentPoint);
else
{
g.DrawLine(Pens.Red, lastPoint, currentPoint);
}
lastPoint = currentPoint;
}
}
}
memory = new MemoryStream();
bmp.Save(memory, ImageFormat.Jpeg);
memory.Position = 0;
}
return memory;
}
