private static void DrawGridQuad(SKCanvas canvas, TmxMap tmxMap)
{
HashSet <Point> points = new HashSet <Point>();
for (int x = 0; x < GetMaxTilesWide(tmxMap); ++x)
{
for (int y = 0; y < GetMaxTilesHigh(tmxMap); ++y)
{
// Add the "top-left" corner of a tile
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y));
// Add all other corners of the tile to our list of grid points
// This is complicated by different map types (espcially staggered isometric)
if (tmxMap.Orientation == TmxMap.MapOrientation.Orthogonal || tmxMap.Orientation == TmxMap.MapOrientation.Isometric)
{
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x + 1, y));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x + 1, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 1));
}
else if (tmxMap.Orientation == TmxMap.MapOrientation.Staggered)
{
bool sx = TmxMath.DoStaggerX(tmxMap, x);
bool sy = TmxMath.DoStaggerY(tmxMap, y);
if (sx)
{
// top-right, bottom-right, and bottom-left
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x + 1, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x - 1, y + 1));
}
else if (sy)
{
// top-right, bottom-right, and bottom-left
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x + 1, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 2));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 1));
}
else if (tmxMap.StaggerAxis == TmxMap.MapStaggerAxis.X)
{
// top-right, bottom-right, and bottom-left
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x + 1, y));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x - 1, y));
}
else if (tmxMap.StaggerAxis == TmxMap.MapStaggerAxis.Y)
{
// top-right, bottom-right, and bottom-left
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 1));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x, y + 2));
points.Add(TmxMath.TileCornerFromGridCoordinates(tmxMap, x - 1, y + 1));
}
}
}
}
// Can take for granted that background is always white in drawing black rectangles
using (SKPaint paint = new SKPaint())
{
paint.Color = SKColors.Black;
paint.Style = SKPaintStyle.Stroke;
paint.StrokeWidth = StrokeWidthThin;
foreach (var p in points)
{
SKRect rc = SKRect.Create(p.X, p.Y, PreviewImage.GridSize, PreviewImage.GridSize);
rc.Offset(-PreviewImage.GridSize * 0.5f, -PreviewImage.GridSize * 0.5f);
canvas.DrawRect(rc, paint);
}
}
}
