public static Tile calculateTile(
final Tile tile, final int srcZoom, final int dstZoom, final int tilesize) {
final TMSUtils.Bounds bounds = TMSUtils.tileBounds(tile.tx, tile.ty, srcZoom, tilesize);
return TMSUtils.latLonToTile(bounds.s, bounds.w, dstZoom, tilesize);
}
/**
* BoundsCropper takes an image (actually, its metadata), a list of user bounds to crop, and a
* zoom level, and gives back the metadata corresponding to the cropped image with the maximum
* zoom level set to the one provided.
*
* <p>Additional details:
*
* <p>If there is only one user bounds, then the cropped image bounds corresponds to that
* singleton bounds. If there is a list of user bounds, then the cropped image bounds corresponds
* to an envelope around the list of user bounds.
*
* <p>The new image bounds are computed from the old using the following two transformations -
* first, the user bounds are capped to the nearest tile boundaries. - second, the bounds from
* above are then intersected with the original image boundaries
*
* <p>The new tile bounds are computed from the new image bounds.
*
* <p>If the user bounds are outside the image bounds (i.e., they have no overlap), then an
* exception is thrown
*
* <p>If the provided zoom level is different from the maximum zoom level in the input metadata,
* then care is taken to set the maximum zoom level of the returned data to the provided zoom
* level.
*
* @param origMetadata
* @param userBounds
* @param zoomLevel
* @return
*/
public static MrsPyramidMetadata getCroppedMetadata(
MrsPyramidMetadata origMetadata, List<Bounds> userBounds, int zoomLevel) {
double minX = Double.POSITIVE_INFINITY, minY = Double.POSITIVE_INFINITY;
double maxX = Double.NEGATIVE_INFINITY, maxY = Double.NEGATIVE_INFINITY;
// if there is a list of user bounds, find the envelope surrounding it
for (Bounds bounds : userBounds) {
if (bounds.w < minX) minX = bounds.w;
if (bounds.s < minY) minY = bounds.s;
if (bounds.e > maxX) maxX = bounds.e;
if (bounds.n > maxY) maxY = bounds.n;
}
Bounds cropBounds = new Bounds(minX, minY, maxX, maxY);
// now cap it to the nearest outside tile boundaries
Bounds cropTileBounds = TMSUtils.tileBounds(cropBounds, zoomLevel, origMetadata.getTilesize());
// get the original image bounds
Bounds imageBounds = Bounds.convertOldToNewBounds(origMetadata.getBounds());
// complain if the user bounds has no overlap with
if (!imageBounds.intersect(cropTileBounds)) {
throw new IllegalArgumentException(
String.format(
"Oops - cropped bounds and image bounds "
+ "do not overlap: cropped bounds=%s, image bounds=%s",
cropTileBounds, imageBounds));
}
// now find the intersection of the cropped bounds and image bounds - this becomes the new
// image bounds
Bounds newImageBounds =
new Bounds(
Math.max(cropTileBounds.w, imageBounds.w),
Math.max(cropTileBounds.s, imageBounds.s),
Math.min(cropTileBounds.e, imageBounds.e),
Math.min(cropTileBounds.n, imageBounds.n));
// find the tile bounds corresponding to the new image bounds - this becomes the new tile bounds
TMSUtils.TileBounds newTileBounds =
TMSUtils.boundsToTile(newImageBounds, zoomLevel, origMetadata.getTilesize());
final TMSUtils.Pixel lowerPx =
TMSUtils.latLonToPixels(
newImageBounds.s, newImageBounds.w, zoomLevel, origMetadata.getTilesize());
final TMSUtils.Pixel upperPx =
TMSUtils.latLonToPixels(
newImageBounds.n, newImageBounds.e, zoomLevel, origMetadata.getTilesize());
final LongRectangle pixelBounds =
new LongRectangle(0, 0, upperPx.px - lowerPx.px, upperPx.py - lowerPx.py);
// time to create the new metadata
MrsPyramidMetadata croppedMetadata = new MrsPyramidMetadata();
croppedMetadata.setPyramid(origMetadata.getPyramid());
croppedMetadata.setBounds(Bounds.convertNewToOldBounds(newImageBounds));
croppedMetadata.setTilesize(origMetadata.getTilesize());
croppedMetadata.setTileType(origMetadata.getTileType());
croppedMetadata.setBands(1);
croppedMetadata.setDefaultValues(origMetadata.getDefaultValues());
// max zoom should be input zoom not origMetadata.getMaxZoomLevel
croppedMetadata.setMaxZoomLevel(zoomLevel);
croppedMetadata.setName(zoomLevel, "" + zoomLevel);
croppedMetadata.setTileBounds(zoomLevel, TileBounds.convertToLongRectangle(newTileBounds));
croppedMetadata.setPixelBounds(zoomLevel, pixelBounds);
croppedMetadata.setProtectionLevel(origMetadata.getProtectionLevel());
return croppedMetadata;
}
