BingMapDataProvider.GetMapSizeInPixels(Double) Method
Returns the map size (in pixels) for the specified zoom level.
Namespace: DevExpress.XtraMap
Assembly: DevExpress.XtraMap.v24.1.dll
NuGet Package: DevExpress.Win.Map
Declaration
Parameters
Name | Type | Description |
---|---|---|
zoomLevel | Double | A double value that specifies the zoom level. |
Returns
Type | Description |
---|---|
MapSize | A MapSize object that is the map size. |
Example
This example illustrates how to implement a custom provider for image tiles. To do this, it is necessary to create a MapDataProviderBase class descendant and assign it to the ImageLayer.DataProvider property.
The sample below shows how to load image tiles from a local cache. This is possible only if you previously downloaded a group of image tiles from one of the available image tile providers. For example, a list of alternative OpenStreetMap image tile providers is available here: OpenStreetMap: Tile usage policy.
Note
If you don’t need to create a custom data provider and only require changing the Uri to the location of image tiles, use the OpenStreetMapDataProvider.TileUriTemplate property.
using System;
using System.Windows.Forms;
using DevExpress.XtraMap;
using System.IO;
using System.Drawing;
using System.Diagnostics;
namespace CustomProvider {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
// Create a map control, set its dock style and add it to the form.
MapControl map = new MapControl();
map.Dock = DockStyle.Fill;
this.Controls.Add(map);
// Create a layer to load image tiles from a local map data provider.
ImageLayer imageTilesLayer = new ImageLayer();
map.Layers.Add(imageTilesLayer);
imageTilesLayer.DataProvider = new LocalProvider();
}
public class LocalProvider : MapDataProviderBase {
readonly SphericalMercatorProjection projection = new SphericalMercatorProjection();
public LocalProvider() {
TileSource = new LocalTileSource(this);
}
public override ProjectionBase Projection {
get {
return projection;
}
}
protected override Size BaseSizeInPixels {
get { return new Size(Convert.ToInt32(LocalTileSource.tileSize * 2), Convert.ToInt32(LocalTileSource.tileSize * 2)); }
}
}
public class LocalTileSource : MapTileSourceBase {
public const int tileSize = 256;
public const int maxZoomLevel = 2;
string directoryPath;
internal static double CalculateTotalImageSize(double zoomLevel) {
if (zoomLevel < 1.0)
return zoomLevel * tileSize * 2;
return Math.Pow(2.0, zoomLevel) * tileSize;
}
public LocalTileSource(ICacheOptionsProvider cacheOptionsProvider) :
base((int)CalculateTotalImageSize(maxZoomLevel), (int)CalculateTotalImageSize(maxZoomLevel), tileSize, tileSize, cacheOptionsProvider) {
DirectoryInfo dir = new DirectoryInfo(Directory.GetCurrentDirectory());
directoryPath = dir.Parent.Parent.FullName;
}
public override Uri GetTileByZoomLevel(int zoomLevel, int tilePositionX, int tilePositionY) {
if (zoomLevel <= maxZoomLevel) {
Uri u = new Uri(string.Format("file://" + directoryPath + "\\openstreetmap.org\\Hybrid_{0}_{1}_{2}.png", zoomLevel, tilePositionX, tilePositionY));
return u;
}
return null;
}
}
}
}