poi/src/java/org/apache/poi/sl/image/ImageHeaderEMF.java

/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
==================================================================== */

package org.apache.poi.sl.image;

import java.awt.Dimension;
import java.awt.Rectangle;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.poi.util.Internal;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.LocaleUtil;

@Internal
public class ImageHeaderEMF {
    private static final Logger LOG = LogManager.getLogger(ImageHeaderEMF.class);

    private static final String EMF_SIGNATURE = " EMF"; // 0x464D4520 (LE)

    // rectangular inclusive-inclusive bounds, in device units, of the smallest
    // rectangle that can be drawn around the image stored in the metafile.
    private final Rectangle deviceBounds;

    public ImageHeaderEMF(final byte[] data, final int off) {
        int offset = off;
        int type = (int)LittleEndian.getUInt(data, offset); offset += 4;
        if (type != 1) {
            LOG.atWarn().log("Invalid EMF picture - invalid type");
            deviceBounds = new Rectangle(0,0,200,200);
            return;
        }
        // ignore header size
        offset += 4;
        int left = LittleEndian.getInt(data, offset); offset += 4;
        int top = LittleEndian.getInt(data, offset); offset += 4;
        int right = LittleEndian.getInt(data, offset); offset += 4;
        int bottom = LittleEndian.getInt(data, offset); offset += 4;
        deviceBounds = new Rectangle(left, top, right-left, bottom-top);
        // ignore frame bounds
        offset += 16;
        String signature = new String(data, offset, EMF_SIGNATURE.length(), LocaleUtil.CHARSET_1252);
        if (!EMF_SIGNATURE.equals(signature)) {
            LOG.atWarn().log("Invalid EMF picture - invalid signature");
        }
    }

    public Dimension getSize() {
        return deviceBounds.getSize();
    }

    public Rectangle getBounds() {
        return deviceBounds;
    }
}