Java BufferedImage Crop autoCrop(BufferedImage source)

Description

Auto crops an image.

License

Apache License

Parameter

Parameter	Description
source	a parameter

Declaration

public static BufferedImage autoCrop(BufferedImage source) 

Method Source Code

//package com.java2s;
/**//from w  ww.j  ava2  s  .  c  om
 * Copyright @ 2008
 *
 * Licensed 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.
 */

import java.awt.*;

import java.awt.image.*;

public class Main {
    private static final int COLOR_WHITE = Color.WHITE.getRGB();
    private static final int margin = 10;

    /**
     * Auto crops an image.
     * @param source
     * @return 
     */
    public static BufferedImage autoCrop(BufferedImage source) {
        int width = source.getWidth();
        int height = source.getHeight();

        int minX = 0;
        int minY = 0;
        int maxX = width;
        int maxY = height;

        // Immediately break the loops when encountering a non-white pixel.
        lable1: for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                if (source.getRGB(x, y) != COLOR_WHITE) {
                    minY = y;
                    break lable1;
                }
            }
        }

        lable2: for (int x = 0; x < width; x++) {
            for (int y = minY; y < height; y++) {
                if (source.getRGB(x, y) != COLOR_WHITE) {
                    minX = x;
                    break lable2;
                }
            }
        }

        lable3: for (int y = height - 1; y >= minY; y--) {
            for (int x = minX; x < width; x++) {
                if (source.getRGB(x, y) != COLOR_WHITE) {
                    maxY = y;
                    break lable3;
                }
            }
        }

        lable4: for (int x = width - 1; x >= minX; x--) {
            for (int y = minY; y < maxY; y++) {
                if (source.getRGB(x, y) != COLOR_WHITE) {
                    maxX = x;
                    break lable4;
                }
            }
        }

        if ((minX - margin) >= 0) {
            minX -= margin;
        }

        if ((minY - margin) >= 0) {
            minY -= margin;
        }

        if ((maxX + margin) <= width) {
            maxX += margin;
        }

        if ((maxY + margin) <= height) {
            maxY += margin;
        }

        // if same size, return the original
        if (minX == 0 && minY == 0 && maxX == width && maxY == height) {
            return source;
        }

        int newWidth = maxX - minX + 1;
        int newHeight = maxY - minY + 1;

        BufferedImage target = new BufferedImage(newWidth, newHeight, source.getType());

        Graphics g = target.getGraphics();
        g.drawImage(source, 0, 0, target.getWidth(), target.getHeight(), minX, minY, maxX + 1, maxY + 1, null);

        g.dispose();

        return target;
    }
}

Related

1. adjustRectToFitImage(BufferedImage image, Rectangle cropRect)
2. autoCrop(BufferedImage source, double tolerance)
3. crop(BufferedImage image, Rectangle clip)
4. crop(BufferedImage input, int x, int y, int width, int height)
5. crop(BufferedImage original, int newSize)