博客

public class ImgCodeUtils {


    public static BufferedImage img_alpha(BufferedImage imgsrc,int alpha) {
        try {
            //创建一个包含透明度的图片,半透明效果必须要存储为png合适才行，存储为jpg，底色为黑色
            BufferedImage back=new BufferedImage(imgsrc.getWidth(), imgsrc.getHeight(), BufferedImage.TYPE_INT_ARGB);
            int width = imgsrc.getWidth();
            int height = imgsrc.getHeight();
            for (int j = 0; j < height; j++) {
                for (int i = 0; i < width; i++) {
                    int rgb = imgsrc.getRGB(i, j);
                    Color color = new Color(rgb);
                    Color newcolor = new Color(color.getRed(), color.getGreen(),color.getBlue(), alpha);
                    back.setRGB(i,j,newcolor.getRGB());
                }
            }
            return back;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public static BufferedImage file2img(String imgpath) {
        try {
            BufferedImage bufferedImage=ImageIO.read(new File(imgpath));
            return bufferedImage;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    //保存图片,extent为格式，"jpg"、"png"等
    public static void img2file(BufferedImage img,String extent,String newfile) {
        try {
            ImageIO.write(img, extent, new File(newfile));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //压缩图片
    public static BufferedImage getBufferedImage(Image src,int scale) {
        int width = ( int ) (src.getWidth( null ) * scale / 100.0 );
        int height = ( int ) (src.getHeight( null ) * scale / 100.0 );
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        bufferedImage.getGraphics().drawImage(src.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0 , 0 , null );
        return  bufferedImage;
    }


    public static BufferedImage scaleByPercentage(BufferedImage inputImage, int newWidth, int newHeight) throws Exception {
        // 获取原始图像透明度类型
        int type = inputImage.getColorModel().getTransparency();
        int width = inputImage.getWidth();
        int height = inputImage.getHeight();
        // 开启抗锯齿
        RenderingHints renderingHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        // 使用高质量压缩
        renderingHints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
        BufferedImage img = new BufferedImage(newWidth, newHeight, type);
        Graphics2D graphics2d = img.createGraphics();
        graphics2d.setRenderingHints(renderingHints);
        graphics2d.drawImage(inputImage, 0, 0, newWidth, newHeight, 0, 0, width, height, null);
        graphics2d.dispose();
        return img;
    }


    public static BufferedImage getUrlByBufferedImage(String url) {
        try {
            URL urlObj = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
            // 连接超时
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setConnectTimeout(25000);
            // 读取超时 --服务器响应比较慢,增大时间
            conn.setReadTimeout(25000);
            conn.setRequestMethod("GET");
            conn.addRequestProperty("Accept-Language", "zh-cn");
            conn.addRequestProperty("Content-type", "image/jpeg");
            conn.addRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727)");
            conn.connect();
            BufferedImage bufImg = ImageIO.read(conn.getInputStream());
            conn.disconnect();
            return bufImg;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 传入的图像必须是正方形的 才会 圆形 如果是长方形的比例则会变成椭圆的
     *
     * @param
     *
     * @return
     * @throws IOException
     */
    public static BufferedImage convertCircular(BufferedImage bi1) throws IOException {

//      BufferedImage bi1 = ImageIO.read(new File(url));

        // 这种是黑色底的
//      BufferedImage bi2 = new BufferedImage(bi1.getWidth(), bi1.getHeight(), BufferedImage.TYPE_INT_RGB);

        // 透明底的图片
        BufferedImage bi2 = new BufferedImage(bi1.getWidth(), bi1.getHeight(), BufferedImage.TYPE_4BYTE_ABGR);
        Ellipse2D.Double shape = new Ellipse2D.Double(0, 0, bi1.getWidth(), bi1.getHeight());
        Graphics2D g2 = bi2.createGraphics();
        g2.setClip(shape);
        // 使用 setRenderingHint 设置抗锯齿
        g2.drawImage(bi1, 0, 0, null);
        // 设置颜色
        g2.setBackground(Color.green);
        g2.dispose();
        return bi2;
    }



}