/**
* @param li ImageLevelInfo object
* @param con JDBC Connection
* @return the resolution for li, based on a random chosen tile
* @throws SQLException
* @throws IOException
*/
protected double[] getPixelResolution(ImageLevelInfo li, Connection con)
throws SQLException, IOException {
double[] result = null;
String statementString = getRandomTileStatement(li);
PreparedStatement s = con.prepareStatement(statementString);
ResultSet r = s.executeQuery();
while (r.next()) {
byte[] tileBytes = getTileBytes(r);
if (tileBytes == null) {
continue;
}
BufferedImage buffImage = null;
li.setCanImageIOReadFromInputStream(true);
try {
buffImage = ImageIO.read(new ByteArrayInputStream(tileBytes));
} catch (IOException e) {
}
if (buffImage == null) {
if (LOGGER.isLoggable(Level.WARNING)) {
LOGGER.warning(
"Image IO cannot read from ByteInputStream,use less efficient jai methods");
}
li.setCanImageIOReadFromInputStream(false);
SeekableStream stream = new ByteArraySeekableStream(tileBytes);
String decoderName = null;
for (String dn : ImageCodec.getDecoderNames(stream)) {
decoderName = dn;
break;
}
ImageDecoder decoder = ImageCodec.createImageDecoder(decoderName, stream, null);
PlanarImage img = PlanarImage.wrapRenderedImage(decoder.decodeAsRenderedImage());
buffImage = img.getAsBufferedImage();
}
Envelope env = getEnvelopeFromResultSet(r);
result =
new double[] {
env.getWidth() / buffImage.getWidth(), env.getHeight() / buffImage.getHeight()
};
break;
}
r.close();
s.close();
return result;
}
