Java BufferedImage Trim trimImageVerticallyHelper(BufferedImage image, int maxToTrim)

Description

A helper method which actually trims an image.

License

Open Source License

Parameter

Parameter	Description
image	image to be trimmed
maxToTrim	the maximum whitespace that can be trimmed off this image

Return

a trimmed image

Declaration

private static BufferedImage trimImageVerticallyHelper(BufferedImage image, int maxToTrim) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.awt.image.BufferedImage;
import java.awt.image.PixelGrabber;

public class Main {
    /**/*from w  w w .j  a  va  2s. c o  m*/
     * A helper method which actually trims an image. This method trims rows.
     *
     * @param image         image to be trimmed
     * @param maxToTrim     the maximum whitespace that can be trimmed off this image
     * @return              a trimmed image
     */
    private static BufferedImage trimImageVerticallyHelper(BufferedImage image, int maxToTrim) {

        try {

            /* Create an one dimensional pixel array to store the image pixels */
            int[] pix = new int[image.getWidth() * image.getHeight()];

            PixelGrabber grab = new PixelGrabber(image, 0, 0, image.getWidth(), image.getHeight(), pix, 0,
                    image.getWidth());

            if (!grab.grabPixels())
                return image;

            int lastClearRow = 0;

            int x;
            int y = 1;

            /* Image is transparent*/
            int alpha = 0;

            /* Image is white (RGB) */
            int red = 255;
            int green = 255;
            int blue = 255;

            /* Iterate over the height of the image */
            while (y < image.getHeight()) {

                /* Reset the width counter */
                x = 0;

                /* Check whether the image is transparent or white if yes perform the trim operation until the entire width of the image */
                while (x < image.getWidth() && ((alpha == 0) || (red == 255 && green == 255 && blue == 255))) {

                    int i = y * image.getWidth() + x;
                    int pixel = pix[i];
                    alpha = (pixel >> 24) & 0xff;
                    red = (pixel >> 16) & 0xff;
                    green = (pixel >> 8) & 0xff;
                    blue = (pixel) & 0xff;
                    x++;
                }

                /* Executed only when the entire row has been checked*/
                if (x == image.getWidth())
                    lastClearRow = y;
                y++;
            }

            int trimmable = Math.min(lastClearRow, maxToTrim);

            /* Trim the image vertically */
            return image.getSubimage(0, trimmable, image.getWidth(), image.getHeight() - trimmable);
        } catch (InterruptedException e) {
            return image;
        }
    }
}

Related

1. trim(final BufferedImage img)
2. trimAroundCenter(BufferedImage img, Point center, Color bgColor)
3. trimImage(BufferedImage image)
4. trimImage(BufferedImage imageToTrim)
5. trimImageHorizontally(BufferedImage image, boolean trimFromEnd, int maxToTrim)
6. trimImg(BufferedImage img, Color backgroundColor)
7. trimLockdown(BufferedImage Img, int y1)
8. trimLockup(BufferedImage Img)
9. trimmedImage(BufferedImage source)