private Rectangle getPrefetchingRegion(
Rectangle loadedTilesBounds, BufferedVirtualSlideImage image, int resIndex) {
Dimension tileSize = image.getTileSize(resIndex);
Dimension tilePrefetchingRadius = getPrefetchingRadiusInTiles(tileSize);
int tileColumns =
(int) Math.ceil(image.getImageSize(resIndex).getWidth() / tileSize.getWidth());
int tileRows = (int) Math.ceil(image.getImageSize(resIndex).getHeight() / tileSize.getHeight());
int x1 = (int) Math.max(loadedTilesBounds.getX() - tilePrefetchingRadius.getWidth(), 0);
int y1 = (int) Math.max(loadedTilesBounds.getY() - tilePrefetchingRadius.getHeight(), 0);
int x2 =
(int) Math.min(loadedTilesBounds.getMaxX() + tilePrefetchingRadius.getWidth(), tileColumns);
int y2 =
(int) Math.min(loadedTilesBounds.getMaxY() + tilePrefetchingRadius.getHeight(), tileRows);
return new Rectangle(x1, y1, x2 - x1, y2 - y1);
}
@Override
public List<Tile> getTilesToPrefetch(
BufferedVirtualSlideImage image, Rectangle loadedImagePart, ImageIndex imageIndex) {
Rectangle loadedTiles =
getLoadedTilesBounds(loadedImagePart, image.getTileSize(imageIndex.getResolutionIndex()));
Rectangle prefetchingRegion =
getPrefetchingRegion(loadedTiles, image, imageIndex.getResolutionIndex());
List<Tile> tilesToPrefetch = new ArrayList<Tile>();
for (int y = prefetchingRegion.y; y < prefetchingRegion.getMaxY(); y++) {
for (int x = prefetchingRegion.x; x < prefetchingRegion.getMaxX(); x++) {
if (!loadedTiles.contains(x, y)) {
tilesToPrefetch.add(new Tile(x, y, imageIndex));
}
}
}
return tilesToPrefetch;
}