/// <summary>
/// Recursively calculates new extents of the map ot cover a certain geo size in meters.
/// </summary>
private static IEnvelope CalcNewExtentsCore(
IPrintableMap map,
IEnvelope oldExtents,
GeoSize newSize,
SizeF paperSize,
ref int depth)
{
depth++;
GeoSize oldSize;
if (map.GetGeodesicSize(oldExtents, out oldSize))
{
const int maxDepth = 5;
double newScale = CalcMapScale(newSize, paperSize);
double oldScale = CalcMapScale(oldSize, paperSize);
if (NumericHelper.Equal(newScale, oldScale, 1e-6) || depth > maxDepth)
{
return(oldExtents);
}
double ratio = newScale / oldScale - 1;
double dx = oldExtents.Width * ratio;
double dy = oldExtents.Height * ratio;
var extents = oldExtents.Inflate(dx, dy);
return(CalcNewExtentsCore(map, extents, newSize, paperSize, ref depth));
}
return(null);
}
private void UpdatePreview(bool fullExtents)
{
int layersCount = _mainMap.Layers.Count;
if (layersCount == 0 &&
(_mainMap.TileProvider == TileProvider.None || _mainMap.Projection.IsEmpty))
{
MessageService.Current.Info("Map is empty. It's not possible to create an overview image.");
return;
}
if (fullExtents && layersCount == 0)
{
MessageService.Current.Info("No layers are loaded to make snapshot.");
return;
}
IEnvelope e = fullExtents ? _mainMap.MaxExtents : _mainMap.Extents;
e = e.Inflate(e.Width * 0.1, e.Height * 0.1); // parameter can be introduced
double ratio = _view.Width / (double)_view.Height;
var exts = e.Adjust(ratio);
var img = GetSnapshot(exts);
if (img == null)
{
MessageService.Current.Warn("Failed to make screenshot.");
return;
}
img.Dx = (exts.MaxX - exts.MinX) / img.Width;
img.Dy = (exts.MaxY - exts.MinY) / img.Height;
img.XllCenter = exts.MinX + 0.5 * img.Dx;
img.YllCenter = exts.MinY + 0.5 * img.Dx; // TODO: Shouldn't this be img.Dy?
img.DownsamplingMode = InterpolationType.HighQualityBicubic;
img.UpsamplingMode = InterpolationType.HighQualityBicubic;
_view.UpdateImage(img);
_view.UpdateLocatorBox(_mainMap.Extents);
}