ImageClip.java Source code

Introduction

Here is the source code for ImageClip.java

Source

//package com.ryanm.util.image;

import java.awt.Graphics;
import java.awt.Polygon;
import java.awt.image.BufferedImage;

/**
 * @author ryanm
 */
public class ImageClip {
    /**
     * Clips the input image to the specified shape
     * 
     * @param image
     *           the input image
     * @param clipVerts
     *           list of x, y pairs defining the clip shape, normalised
     *           to image dimensions (think texture coordinates)
     * @return The smallest image containing those pixels that fall
     *         inside the clip shape
     */
    public static BufferedImage clip(BufferedImage image, float... clipVerts) {
        assert clipVerts.length >= 6;
        assert clipVerts.length % 2 == 0;

        int[] xp = new int[clipVerts.length / 2];
        int[] yp = new int[xp.length];

        int minX = image.getWidth(), minY = image.getHeight(), maxX = 0, maxY = 0;

        for (int j = 0; j < xp.length; j++) {
            xp[j] = Math.round(clipVerts[2 * j] * image.getWidth());
            yp[j] = Math.round(clipVerts[2 * j + 1] * image.getHeight());

            minX = Math.min(minX, xp[j]);
            minY = Math.min(minY, yp[j]);
            maxX = Math.max(maxX, xp[j]);
            maxY = Math.max(maxY, yp[j]);
        }

        for (int i = 0; i < xp.length; i++) {
            xp[i] -= minX;
            yp[i] -= minY;
        }

        Polygon clip = new Polygon(xp, yp, xp.length);
        BufferedImage out = new BufferedImage(maxX - minX, maxY - minY, image.getType());
        Graphics g = out.getGraphics();
        g.setClip(clip);

        g.drawImage(image, -minX, -minY, null);
        g.dispose();

        return out;
    }
}