/// <inheritdoc/>
public Stream GetImageStream(int x, int y, int zoom)
{
// calc rect from tile key
var rect = GeoTransform.TileToPtvMercatorAtZoom(x, y, zoom);
return(GetImageStream(rect.Left, rect.Top, rect.Right, rect.Bottom, 256, 256));
}
/// <summary> Creates a stream object containing the image at position (<paramref name="x"/>,<paramref name="y"/>)
/// and zoom level <paramref name="zoom"/>. </summary>
/// <param name="x"> X-coordinate for the requested tile. </param>
/// <param name="y"> Y-coordinate for the requested tile. </param>
/// <param name="zoom"> Zoom level. </param>
/// <returns> The stream object containing the image of the tile. </returns>
public Stream GetImageStream(int x, int y, int zoom)
{
// Create a bitmap of size 256x256
using (var bmp = new Bitmap(256, 256))
{
// calc rect from tile key
var rect = GeoTransform.TileToPtvMercatorAtZoom(x, y, zoom);
// PTV_Mercator to Image function
Func <double, double, Point> mercatorToImage =
(mercatorX, mercatorY) => new Point(
x = (int)((mercatorX - rect.Left) / (rect.Right - rect.Left) * 256),
y = 256 + (int)-((mercatorY - rect.Top) / (rect.Bottom - rect.Top) * 256));
// get graphics from bitmap
using (var graphics = Graphics.FromImage(bmp))
{
// query the provider for the items in the envelope
var result = Provider.QueryBBox(rect.Left, rect.Top, rect.Right, rect.Bottom, Theme.RequiredFields);
foreach (var item in result)
{
// create GDI path from wkb
var path = WkbToGdi.Parse(item.Wkb, mercatorToImage);
// evalutate style
var style = Theme.Mapping(item);
// fill polyong
if (style.Fill != null)
{
graphics.FillPath(style.Fill, path);
}
// draw outline
if (style.Outline != null)
{
graphics.DrawPath(style.Outline, path);
}
}
}
// crate a memory stream
var stream = new MemoryStream();
// save image to stream
bmp.Save(stream, ImageFormat.Png);
// rewind stream
stream.Seek(0, SeekOrigin.Begin);
return(stream);
}
}
/// <inheritdoc/>
public Stream GetImageStream(int tileX, int tileY, int zoom)
{
Rect rect = GeoTransform.TileToPtvMercatorAtZoom(tileX, tileY, zoom);
return(GetImageStream(rect.Left, rect.Top, rect.Right, rect.Bottom, 256, 256));
}