Calculates the bounds of the non-transparent parts of the given image. - Java 2D Graphics

Java examples for 2D Graphics:Image

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Description

Calculates the bounds of the non-transparent parts of the given image.

Demo Code


//package com.java2s;
import java.awt.*;

import java.awt.image.*;

public class Main {
    /**/*from   w  w w  .  j  av  a 2s. c o  m*/
     * Calculates the bounds of the non-transparent parts of the given image.
     * @param p the image
     * @return the bounds of the non-transparent area
     */
    public static Rectangle getSelectedBounds(BufferedImage p) {
        int width = p.getWidth();
        int height = p.getHeight();
        int maxX = 0, maxY = 0, minX = width, minY = height;
        boolean anySelected = false;
        int y1;
        int[] pixels = null;

        for (y1 = height - 1; y1 >= 0; y1--) {
            pixels = getRGB(p, 0, y1, width, 1, pixels);
            for (int x = 0; x < minX; x++) {
                if ((pixels[x] & 0xff000000) != 0) {
                    minX = x;
                    maxY = y1;
                    anySelected = true;
                    break;
                }
            }
            for (int x = width - 1; x >= maxX; x--) {
                if ((pixels[x] & 0xff000000) != 0) {
                    maxX = x;
                    maxY = y1;
                    anySelected = true;
                    break;
                }
            }
            if (anySelected)
                break;
        }
        pixels = null;
        for (int y = 0; y < y1; y++) {
            pixels = getRGB(p, 0, y, width, 1, pixels);
            for (int x = 0; x < minX; x++) {
                if ((pixels[x] & 0xff000000) != 0) {
                    minX = x;
                    if (y < minY)
                        minY = y;
                    anySelected = true;
                    break;
                }
            }
            for (int x = width - 1; x >= maxX; x--) {
                if ((pixels[x] & 0xff000000) != 0) {
                    maxX = x;
                    if (y < minY)
                        minY = y;
                    anySelected = true;
                    break;
                }
            }
        }
        if (anySelected)
            return new Rectangle(minX, minY, maxX - minX + 1, maxY - minY
                    + 1);
        return null;
    }

    /**
     * A convenience method for getting ARGB pixels from an image. This tries to avoid the performance
     * penalty of BufferedImage.getRGB unmanaging the image.
     * @param image   a BufferedImage object
     * @param x       the left edge of the pixel block
     * @param y       the right edge of the pixel block
     * @param width   the width of the pixel arry
     * @param height  the height of the pixel arry
     * @param pixels  the array to hold the returned pixels. May be null.
     * @return the pixels
     * @see #setRGB
     */
    public static int[] getRGB(BufferedImage image, int x, int y,
            int width, int height, int[] pixels) {
        int type = image.getType();
        if (type == BufferedImage.TYPE_INT_ARGB
                || type == BufferedImage.TYPE_INT_RGB)
            return (int[]) image.getRaster().getDataElements(x, y, width,
                    height, pixels);
        return image.getRGB(x, y, width, height, pixels, 0, width);
    }
}

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