BackgroundFactory.java

package cn.dreampie.common.plugin.patchca;

import cn.dreampie.common.plugin.patchca.background.BackgroundFactory;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * Created by wangrenhui on 13-12-31.
 */
class SimpleBackgroundFactory implements BackgroundFactory {
    private Random random = new Random();

    public void fillBackground(BufferedImage image) {
        Graphics2D graphics = (Graphics2D) image.getGraphics();

        // 验证码图片的宽高
        int imgWidth = image.getWidth();
        int imgHeight = image.getHeight();

        // 填充为白色背景
        graphics.setColor(Color.WHITE);
        graphics.fillRect(0, 0, imgWidth, imgHeight);

        // 画100个噪点(颜色及位置随机)
        for (int i = 0; i < 50; i++) {
            // 随机颜色
            // int rInt = random.nextInt(255);
            // int gInt = random.nextInt(255);
            // int bInt = random.nextInt(255);

            graphics.setColor(new Color(102, 102, 102));

            // 随机位置
            int xInt = random.nextInt(imgWidth - 3);
            int yInt = random.nextInt(imgHeight - 2);

            // 随机旋转角度
            int sAngleInt = random.nextInt(360);
            int eAngleInt = random.nextInt(360);

            // 随机大小
            int wInt = random.nextInt(6);
            int hInt = random.nextInt(6);

            graphics.fillArc(xInt, yInt, wInt, hInt, sAngleInt, eAngleInt);

            // 画5条干扰线
            // if (i % 20 == 0) {
            // int xInt2 = random.nextInt(imgWidth);
            // int yInt2 = random.nextInt(imgHeight);
            // graphics.drawLine(xInt, yInt, xInt2, yInt2);
            // }
        }
        graphics.setRenderingHints(new RenderingHints(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON));
        int cp = 4 + random.nextInt(3);
        int[] xPoints = new int[cp];
        int[] yPoints = new int[cp];
        imgWidth -= 10;
        for (int i = 0; i < cp; i++) {
            xPoints[i] = (int) ((int) 5 + (i * imgWidth) / (cp - 1));
            yPoints[i] = (int) (imgHeight * (random.nextDouble() * 0.5 + 0.2));
        }
        int subsections = 6;
        int[] xPointsSpline = new int[(cp - 1) * subsections];
        int[] yPointsSpline = new int[(cp - 1) * subsections];
        for (int i = 0; i < cp - 1; i++) {
            double x0 = i > 0 ? xPoints[i - 1] : 2 * xPoints[i]
                    - xPoints[i + 1];
            double x1 = xPoints[i];
            double x2 = xPoints[i + 1];
            double x3 = (i + 2 < cp) ? xPoints[i + 2] : 2 * xPoints[i + 1]
                    - xPoints[i];
            double y0 = i > 0 ? yPoints[i - 1] : 2 * yPoints[i]
                    - yPoints[i + 1];
            double y1 = yPoints[i];
            double y2 = yPoints[i + 1];
            double y3 = (i + 2 < cp) ? yPoints[i + 2] : 2 * yPoints[i + 1]
                    - yPoints[i];
            for (int j = 0; j < subsections; j++) {
                xPointsSpline[i * subsections + j] = (int) catmullRomSpline(
                        x0, x1, x2, x3, 1.0 / subsections * j);
                yPointsSpline[i * subsections + j] = (int) catmullRomSpline(
                        y0, y1, y2, y3, 1.0 / subsections * j);
            }
        }
        for (int i = 0; i < xPointsSpline.length - 1; i++) {
            //graphics.setColor(colorFactory.getColor(i));
            graphics.setColor(new Color(102, 102, 102));
            graphics.setStroke(new BasicStroke(0.2f + 2 * random
                    .nextFloat()));
            graphics.drawLine(xPointsSpline[i], yPointsSpline[i],
                    xPointsSpline[i + 1], yPointsSpline[i + 1]);
        }

    }

    private double hermiteSpline(double x1, double a1, double x2,
                                 double a2, double t) {
        double t2 = t * t;
        double t3 = t2 * t;
        double b = -a2 - 2.0 * a1 - 3.0 * x1 + 3.0 * x2;
        double a = a2 + a1 + 2.0 * x1 - 2.0 * x2;
        return a * t3 + b * t2 + a1 * t + x1;
    }

    private double catmullRomSpline(double x0, double x1, double x2,
                                    double x3, double t) {
        double a1 = (x2 - x0) / 2;
        double a2 = (x3 - x1) / 2;
        return hermiteSpline(x1, a1, x2, a2, t);
    }
}