JPEGImageWriter.java 文件源码

/**
 * Finds all DQT marker segments and returns all the q
 * tables as a single array of JPEGQTables.
 */
private JPEGQTable [] collectQTablesFromMetadata
    (JPEGMetadata metadata) {
    ArrayList<DQTMarkerSegment.Qtable> tables = new ArrayList<>();
    Iterator<MarkerSegment> iter = metadata.markerSequence.iterator();
    while (iter.hasNext()) {
        MarkerSegment seg = iter.next();
        if (seg instanceof DQTMarkerSegment) {
            DQTMarkerSegment dqt =
                (DQTMarkerSegment) seg;
            tables.addAll(dqt.tables);
        }
    }
    JPEGQTable [] retval = null;
    if (tables.size() != 0) {
        retval = new JPEGQTable[tables.size()];
        for (int i = 0; i < retval.length; i++) {
            retval[i] =
                new JPEGQTable(tables.get(i).data);
        }
    }
    return retval;
}