public CelestialGrid(string name, int rows, int columns)
{
points = new GridPoint[rows, columns];
Name = name;
Rows = rows;
Columns = columns;
for (int i = 0; i < Rows; i++)
{
for (int j = 0; j < Columns; j++)
{
double latitude = i * 10 - Rows / 2 * 10;
double longitude = j * 15;
points[i, j] = new GridPoint(longitude, latitude);
points[i, j].RowIndex = i;
points[i, j].ColumnIndex = j;
}
}
}
private void DrawGrid(IMapContext map, Pen penGrid, CelestialGrid grid)
{
bool isAnyPoint = false;
// Azimuths
for (int j = 0; j < grid.Columns; j++)
{
var segments = grid.Column(j)
.Select(p => Angle.Separation(grid.ToHorizontal(p, map), map.Center) < map.ViewAngle ? p : null)
.Split(p => p == null, true);
foreach (var segment in segments)
{
for (int k = 0; k < 2; k++)
{
if (segment.First().RowIndex > 1)
{
segment.Insert(0, grid[segment.First().RowIndex - 1, j]);
}
}
for (int k = 0; k < 2; k++)
{
if (segment.Last().RowIndex < grid.Rows - 2)
{
segment.Add(grid[segment.Last().RowIndex + 1, j]);
}
}
PointF[] refPoints = new PointF[2];
for (int k = 0; k < 2; k++)
{
var coord = grid.FromHorizontal(map.Center, map);
coord.Longitude = segment[0].Longitude;
coord.Latitude += -map.ViewAngle + k * (map.ViewAngle * 2);
coord.Latitude = Math.Min(coord.Latitude, 80);
coord.Latitude = Math.Max(coord.Latitude, -80);
var refHorizontal = grid.ToHorizontal(coord, map);
refPoints[k] = map.Project(refHorizontal);
}
DrawGroupOfPoints(map, penGrid, segment.Select(s => map.Project(grid.ToHorizontal(s, map))).ToArray(), refPoints);
isAnyPoint = true;
}
}
// Altitude circles
for (int i = 0; i < grid.Rows; i++)
{
var segments = grid.Row(i)
.Select(p => Angle.Separation(grid.ToHorizontal(p, map), map.Center) < map.ViewAngle ? p : null)
.Split(p => p == null, true).ToList();
// segment that starts with point "0 degrees"
var seg0 = segments.FirstOrDefault(s => s.First().ColumnIndex == 0);
// segment that ends with point "345 degrees"
var seg23 = segments.FirstOrDefault(s => s.Last().ColumnIndex == 23);
// join segments into one
if (seg0 != null && seg23 != null && seg0 != seg23)
{
segments.Remove(seg0);
seg23.AddRange(seg0);
}
foreach (var segment in segments)
{
if (segment.Count == 24)
{
map.Graphics.DrawClosedCurve(penGrid, segment.Select(s => map.Project(grid.ToHorizontal(s, map))).ToArray());
}
else
{
for (int k = 0; k < 2; k++)
{
int col = segment.First().ColumnIndex;
if (col == 0)
{
segment.Insert(0, grid[i, 23]);
}
else
{
segment.Insert(0, grid[i, col - 1]);
}
}
for (int k = 0; k < 2; k++)
{
int col = segment.Last().ColumnIndex;
if (col < 23)
{
segment.Add(grid[i, col + 1]);
}
else if (col == 23)
{
segment.Add(grid[i, 0]);
}
}
PointF[] refPoints = new PointF[2];
for (int k = 0; k < 2; k++)
{
var coord = grid.FromHorizontal(map.Center, map);
coord.Longitude += -map.ViewAngle + k * (map.ViewAngle * 2);
coord.Latitude = segment[0].Latitude;
var refHorizontal = grid.ToHorizontal(coord, map);
refPoints[k] = map.Project(refHorizontal);
}
if (!map.IsOutOfScreen(refPoints[0]) || !map.IsOutOfScreen(refPoints[1]))
{
refPoints = map.LineScreenIntersection(refPoints[0], refPoints[1]);
}
DrawGroupOfPoints(map, penGrid, segment.Select(s => map.Project(grid.ToHorizontal(s, map))).ToArray(), refPoints);
}
isAnyPoint = true;
}
}
// Special case: there are no points visible
// on the screen at the current position and zoom.
// Then we select one point that is closest to screen senter.
if (!isAnyPoint)
{
GridPoint closestPoint = grid.Points.OrderBy(p => Angle.Separation(grid.ToHorizontal(p, map), map.Center)).First();
{
var segment = new List <GridPoint>();
segment.Add(closestPoint);
int i = closestPoint.RowIndex;
for (int k = 0; k < 2; k++)
{
int col = segment.First().ColumnIndex;
if (col == 0)
{
segment.Insert(0, grid[i, 23]);
}
else
{
segment.Insert(0, grid[i, col - 1]);
}
}
for (int k = 0; k < 2; k++)
{
int col = segment.Last().ColumnIndex;
if (col < 23)
{
segment.Add(grid[i, col + 1]);
}
else if (col == 23)
{
segment.Add(grid[i, 0]);
}
}
PointF[] refPoints = new PointF[2];
for (int k = 0; k < 2; k++)
{
var coord = grid.FromHorizontal(map.Center, map);
coord.Longitude += -map.ViewAngle + k * (map.ViewAngle * 2);
coord.Latitude = segment[0].Latitude;
var refHorizontal = grid.ToHorizontal(coord, map);
refPoints[k] = map.Project(refHorizontal);
}
if (!map.IsOutOfScreen(refPoints[0]) || !map.IsOutOfScreen(refPoints[1]))
{
refPoints = map.LineScreenIntersection(refPoints[0], refPoints[1]);
}
DrawGroupOfPoints(map, penGrid, segment.Select(s => map.Project(grid.ToHorizontal(s, map))).ToArray(), refPoints);
}
{
var segment = new List <GridPoint>();
segment.Add(closestPoint);
int j = closestPoint.ColumnIndex;
for (int k = 0; k < 2; k++)
{
if (segment.First().RowIndex > 1)
{
segment.Insert(0, grid[segment.First().RowIndex - 1, j]);
}
}
for (int k = 0; k < 2; k++)
{
if (segment.Last().RowIndex < grid.Rows - 2)
{
segment.Add(grid[segment.Last().RowIndex + 1, j]);
}
}
PointF[] refPoints = new PointF[2];
for (int k = 0; k < 2; k++)
{
var coord = grid.FromHorizontal(map.Center, map);
coord.Longitude = segment[0].Longitude;
coord.Latitude += -map.ViewAngle + k * (map.ViewAngle * 2);
coord.Latitude = Math.Min(coord.Latitude, 80);
coord.Latitude = Math.Max(coord.Latitude, -80);
var refHorizontal = grid.ToHorizontal(coord, map);
refPoints[k] = map.Project(refHorizontal);
}
DrawGroupOfPoints(map, penGrid, segment.Select(s => map.Project(grid.ToHorizontal(s, map))).ToArray(), refPoints);
}
}
}