不依赖第三方的图片缩放工具类

痛定思痛。 2022-10-10 06:05 117阅读 0赞

public class PicUtils { 
        private static int width;
        private static int height;
        private static BufferedImage img;
        
        /** * 强制压缩、放大 * @param destFile * @param w * @param h * @throws IOException */
        private static void resize(String destFile, int w, int h) throws IOException { 
            BufferedImage bufferedImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            bufferedImage.getGraphics().fillRect(0, 0, w, h);
            bufferedImage.getGraphics().drawImage(img, 0, 0, w, h, null);//将原图片画到新图片上
            //输出新图片
            FileOutputStream out = new FileOutputStream(destFile);
    
            ImageIO.write(bufferedImage, destFile.substring(destFile.lastIndexOf('.') + 1), out);
            out.close();
        }
        
        /** * 按照固定的比例缩放图片 * @param sourceFile 源图片 * @param destFile 目标图片 * @param scale 缩放比例 * @throws IOException */
        public static void resize(String sourceFile, String destFile, double scale) throws IOException { 
            img = ImageIO.read(new File(sourceFile));
            width = img.getWidth();
            height = img.getHeight();
    
            int w = (int) (width * scale);
            int h = (int) (height * scale);
            resize(destFile, w, h);
        }
    
    
        /** * 以高度为基准，等比例缩放图片 * @param sourceFile 源图片 * @param destFile 目标图片 * @param h 作为基准的高度 * @throws IOException */
        public static void resizeByHeight(String sourceFile, String destFile, int h) throws IOException { 
            img = ImageIO.read(new File(sourceFile));
            width = img.getWidth();
            height = img.getHeight();
            int w = width * h / height;
            resize(destFile, w, h);
        }
    
        /** * 以宽度为基准，等比例缩放图片 * @param sourceFile 源图片 * @param destFile 目标图片 * @param w 作为基准的宽度 * @throws IOException */
        public static void resizeByWidth(String sourceFile, String destFile, int w) throws IOException { 
            img = ImageIO.read(new File(sourceFile));
            width = img.getWidth();
            height = img.getHeight();
            int h = (height * w) / width;
            resize(destFile, w, h);
        }
    
        public static void main(String args[]) { 
            try { 
                String sourceFile = "e:\\1920X1050.jpg";
                resize(sourceFile, "e:/b1.jpg", 0.5);
                resizeByHeight(sourceFile,"e:/b2.jpg",200);
                resizeByWidth(sourceFile,"e:/b3.jpg",200);
            } catch (IOException e) { 
                e.printStackTrace();
            }
    
        }
    }