Example usage for com.google.gwt.maps.client HasMapCanvasProjection fromLatLngToDivPixel

Introduction

In this page you can find the example usage for com.google.gwt.maps.client HasMapCanvasProjection fromLatLngToDivPixel.

Prototype

public HasPoint fromLatLngToDivPixel(HasLatLng latLng);

Source Link

Document

Computes the pixel coordinates of the given geographical location in the DOM element that holds the draggable map.

Usage

From source file:com.mashery.examples.api.client.weatherbug.WeatherBugOverlayView.java

License:Open Source License

@Override
public void draw() {
    HasLatLngBounds bounds = getMap().getBounds();
    HasMapCanvasProjection ovrPrj = getProjection();
    HasPoint ovrNE = ovrPrj.fromLatLngToDivPixel(bounds.getNorthEast());
    HasPoint ovrSW = ovrPrj.fromLatLngToDivPixel(bounds.getSouthWest());

    div.getStyle().setLeft(ovrSW.getX(), Unit.PX);
    div.getStyle().setTop(ovrNE.getY(), Unit.PX);
    div.getStyle().setWidth(ovrNE.getX() - ovrSW.getX(), Unit.PX);
    div.getStyle().setHeight(ovrSW.getY() - ovrNE.getY(), Unit.PX);

    String endpoint = WEATHERBUG_ENDPOINT.replace("${layerType}", layerType.getPath());
    HashSet<TileKey> usedTiles = new HashSet<TileKey>();

    int zoom = getMap().getZoom();
    double scale = Math.pow(2d, zoom);
    HasProjection prj = getMap().getProjection();
    LatLng nwLatLng = new LatLng(bounds.getNorthEast().getLatitude(), bounds.getSouthWest().getLongitude());
    HasPoint nwRaw = prj.fromLatLngToPoint(nwLatLng);
    LatLng seLatLng = new LatLng(bounds.getSouthWest().getLatitude(), bounds.getNorthEast().getLongitude());
    HasPoint seRaw = prj.fromLatLngToPoint(seLatLng);

    Point nw = new Point(Math.floor(nwRaw.getX() * scale), Math.floor(nwRaw.getY() * scale));
    Point se = new Point(Math.floor(seRaw.getX() * scale), Math.floor(seRaw.getY() * scale));

    double offsetX = nw.getX() % 256d;
    double offsetY = nw.getY() % 256d;
    Point startPoint = new Point(nw.getX() - offsetX, nw.getY() - offsetY);

    while (startPoint.getY() < se.getY()) {
        Point p = new Point(startPoint.getX(), startPoint.getY());
        startPoint = new Point(startPoint.getX(), startPoint.getY() + 256);
        while (p.getX() < se.getX()) {
            int tx = (int) p.getX() / 256;
            int ty = (int) p.getY() / 256;

            TileKey tileKey = new TileKey(tx, ty, zoom);
            usedTiles.add(tileKey);//from   w  w w  .j a va 2  s.  com

            ImageElement img = tiles.remove(tileKey);
            if (img == null) {
                img = Document.get().createImageElement();
                img.getStyle().setBorderStyle(BorderStyle.NONE);
                img.getStyle().setBorderWidth(0d, Unit.PX);
                img.getStyle().setPosition(Position.ABSOLUTE);

                StringBuilder buf = new StringBuilder(endpoint);
                buf.append("&tx=").append(tx);
                buf.append("&ty=").append(ty);
                buf.append("&zm=").append(zoom);
                img.setSrc(buf.toString());

                div.appendChild(img);
            } else {
                img.getStyle().setVisibility(Visibility.VISIBLE);
            }

            img.getStyle().setLeft(p.getX() - nw.getX(), Unit.PX);
            img.getStyle().setTop(p.getY() - nw.getY(), Unit.PX);
            img.getStyle().setWidth(256d, Unit.PX);
            img.getStyle().setHeight(256d, Unit.PX);
            tiles.put(tileKey, img);

            p = new Point(p.getX() + 256, p.getY());
        }
    }

    for (Iterator<Map.Entry<TileKey, ImageElement>> i = tiles.entrySet().iterator(); i.hasNext();) {
        Map.Entry<TileKey, ImageElement> entry = i.next();
        if (!usedTiles.remove(entry.getKey())) {
            if (tiles.size() > TILE_CACHE_SIZE) {
                i.remove();
                entry.getValue().removeFromParent();
            } else {
                entry.getValue().getStyle().setVisibility(Visibility.HIDDEN);
            }
        }
    }
}

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