# Class VectorMapEngine

java.lang.Object
com.codename1.maps.vector.VectorMapEngine

public final class VectorMapEngine extends Object

The pure-Codename One map renderer behind `MapView` (and the `NativeMap` fallback).

It maintains the camera (center + fractional zoom), pulls tiles from a `TileSource`, rasterizes vector tiles once into 256px buffers (or decodes raster tiles), caches them in an LRU `TileCache`, and on each paint blits the visible buffers scaled to the fractional zoom and places labels with the `LabelEngine`. All drawing uses the framework `Graphics` API -- there is no native peer.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `VectorMapEngine(TileSource source, MapStyle style)`
  Creates an engine over `source`, styled by `style`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `clearCache()`
  Drops all cached tiles (e.g. on low memory).
  `void`
  `fitBounds(MapBounds bounds, int padding)`
  Moves the camera so `bounds` fits the viewport inset by `padding`.
  `LatLng`
  `getCenter()`
  The geographic coordinate at the center of the viewport.
  `double`
  `getMaxZoom()`
  The largest zoom level the tile source serves.
  `double`
  `getMinZoom()`
  The smallest zoom level the tile source serves.
  `double`
  `getPixelRatio()`
  The current device pixel ratio (see `setPixelRatio(double)`).
  `TileSource`
  `getSource()`
  The active tile source.
  `MapStyle`
  `getStyle()`
  The active style.
  `MapBounds`
  `getVisibleBounds()`
  The geographic bounds currently visible, or null before layout.
  `double`
  `getZoom()`
  The current fractional zoom level.
  `boolean`
  `hasPendingTiles()`
  Whether any tile requested for the current view is still loading (i.e. the basemap is not yet fully rendered).
  `Point`
  `latLngToScreen(LatLng coord)`
  Geographic to component-relative pixel.
  `void`
  `paint(Graphics g, int originX, int originY, int width, int height)`
  Paints the basemap and labels into `g`, offset by `originX,originY`.
  `void`
  `panPixels(double dx, double dy)`
  Pans the camera by a pixel delta (used for drag gestures).
  `LatLng`
  `screenToLatLng(int x, int y)`
  Component-relative pixel to geographic.
  `void`
  `setCenter(LatLng center)`
  Recenters the camera at `center`, keeping the current zoom.
  `void`
  `setPixelRatio(double ratio)`
  Sets the device pixel ratio: physical pixels per logical (256px) map pixel.
  `void`
  `setRepaintCallback(Runnable r)`
  Sets the callback invoked (on the EDT) whenever a tile finishes loading and the map needs to repaint.
  `void`
  `setSource(TileSource source)`
  Replaces the tile source, clearing cached tiles.
  `void`
  `setStyle(MapStyle style)`
  Replaces the style, clearing rendered tiles so they redraw.
  `void`
  `setViewport(int width, int height)`
  Sets the pixel size of the viewport (called by the host component on layout before painting and coordinate conversion).
  `void`
  `setZoom(double zoom)`
  Sets the zoom level, clamped to the source's min/max.
  `void`
  `zoomAround(double newZoom, int sx, int sy)`
  Zooms to `newZoom` while keeping the geographic point currently under the component pixel `sx,sy` fixed (used for pinch and double-tap).

  ### Methods inherited from class Object

  `clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### VectorMapEngine

    public VectorMapEngine(TileSource source, MapStyle style)
    Creates an engine over `source`, styled by `style`.

- ## Method Details

  - ### setRepaintCallback

    public void setRepaintCallback(Runnable r)
    Sets the callback invoked (on the EDT) whenever a tile finishes loading and the map needs to repaint.

  - ### setSource

    public void setSource(TileSource source)
    Replaces the tile source, clearing cached tiles.

  - ### getSource

    public TileSource getSource()
    The active tile source.

  - ### setStyle

    public void setStyle(MapStyle style)
    Replaces the style, clearing rendered tiles so they redraw.

  - ### getStyle

    public MapStyle getStyle()
    The active style.

  - ### setCenter

    public void setCenter(LatLng center)
    Recenters the camera at `center`, keeping the current zoom.

  - ### getCenter

    public LatLng getCenter()
    The geographic coordinate at the center of the viewport.

  - ### setZoom

    public void setZoom(double zoom)
    Sets the zoom level, clamped to the source's min/max.

  - ### getZoom

    public double getZoom()
    The current fractional zoom level.

  - ### getMinZoom

    public double getMinZoom()
    The smallest zoom level the tile source serves.

  - ### getMaxZoom

    public double getMaxZoom()
    The largest zoom level the tile source serves.

  - ### setViewport

    public void setViewport(int width, int height)
    Sets the pixel size of the viewport (called by the host component on layout before painting and coordinate conversion).

  - ### setPixelRatio

    public void setPixelRatio(double ratio)
    Sets the device pixel ratio: physical pixels per logical (256px) map pixel. On a 3x retina screen pass 3 so a tile spans 768 device pixels and the map shows the same area it would on a 1x screen. Values <= 0 are ignored. Changing it discards rendered tiles so they re-rasterize at the new resolution.

  - ### getPixelRatio

    public double getPixelRatio()
    The current device pixel ratio (see `setPixelRatio(double)`).

  - ### hasPendingTiles

    public boolean hasPendingTiles()
    Whether any tile requested for the current view is still loading (i.e. the basemap is not yet fully rendered). Goes true after the first paint that needs uncached tiles and back to false once they have all arrived. Best-effort readiness signal (tile bookkeeping happens on the EDT).

  - ### latLngToScreen

    public Point latLngToScreen(LatLng coord)
    Geographic to component-relative pixel.

  - ### panPixels

    public void panPixels(double dx, double dy)
    Pans the camera by a pixel delta (used for drag gestures). A positive `dx` moves the map content to the right.

  - ### zoomAround

    public void zoomAround(double newZoom, int sx, int sy)
    Zooms to `newZoom` while keeping the geographic point currently under the component pixel `sx,sy` fixed (used for pinch and double-tap).

  - ### screenToLatLng

    public LatLng screenToLatLng(int x, int y)
    Component-relative pixel to geographic.

  - ### getVisibleBounds

    public MapBounds getVisibleBounds()
    The geographic bounds currently visible, or null before layout.

  - ### fitBounds

    public void fitBounds(MapBounds bounds, int padding)
    Moves the camera so `bounds` fits the viewport inset by `padding`.

  - ### paint

    public void paint(Graphics g, int originX, int originY, int width, int height)
    Paints the basemap and labels into `g`, offset by `originX,originY`. The caller is responsible for clipping to the component bounds and for drawing overlays (markers/shapes) afterwards.

  - ### clearCache

    public void clearCache()
    Drops all cached tiles (e.g. on low memory).