java 图片处理

java处理图片

// 获取原始图片流
BufferedImage originalBI = ImageIO.read(new File("D://in.jpg"));

// 获取原始图片宽高
int originalWidth = originalBI.getWidth();
int originalHeight = originalBI.getHeight();

// 设置缩放图片宽高
int scaledWidth = originalWidth * 2;
int scaledHeigth = originalHeight * 2;
// int scaledWidth = originalWidth / 2;
// int scaledHeigth = originalHeight / 2;

// 设置缩放图片流
BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeigth, BufferedImage.TYPE_INT_RGB);

// 设置缩放图片画笔
Graphics2D g = scaledBI.createGraphics();
g.setComposite(AlphaComposite.Src);

// 绘制缩放图片
g.drawImage(originalBI, 0, 0, scaledWidth, scaledHeigth, null);
g.dispose();

// 输出缩放图片
ImageIO.write(scaledBI, "jpg", new FileOutputStream(new File("D://out.jpg")));

thumbnailator处理图片(压缩、裁切、旋转、添加水印)

/*
* java工程图片压缩 添加thumbnailator-0.4.7.jar(Build Path --> Add to Build Path)
* thumbnailator 是一个用来生成图像缩略图、裁切、旋转、添加水印等操作的 Java 类库
*/

// 原图
String originalImage = "images/image.jpg";

/*
* 指定大小(默认按比例)进行缩放
* size(width,height)
* 若图片横比200小，高比300小，不变
* 若图片横比200小，高比300大，高缩小到300，图片比例不变
* 若图片横比200大，高比300小，横缩小到200，图片比例不变
* 若图片横比200大，高比300大，图片按比例缩小，横为200或高为300
*/
Thumbnails.of(originalImage).size(200, 300).toFile("images/image_200x300.jpg");

/*
* 不按照比例，指定大小进行缩放
* keepAspectRatio(false)
*/
Thumbnails.of(originalImage).size(200, 300).keepAspectRatio(false).toFile("images/image_200x300_fixed.jpg");

/*
* 按照比例进行缩放
* scale(比例)
*/
Thumbnails.of(originalImage).scale(0.5f).toFile("images/image_50%.jpg");
Thumbnails.of(originalImage).scale(1.5f).toFile("images/image_150%.jpg");

/*
* 旋转
* rotate(角度),正数：顺时针 负数：逆时针
*/
Thumbnails.of(originalImage).size(200, 300).rotate(90).toFile("images/image_200x300_+90.jpg");
Thumbnails.of(originalImage).scale(1.0f).rotate(-90).toFile("images/image_-90.jpg");

/*
* 水印
* watermark(位置，水印图，透明度)
* outputQuality(比例)合成图片按比例质量输出
*/
BufferedImage waterImage = ImageIO.read(new File("images/watermark.jpg"));

Thumbnails.of(originalImage).scale(1.0f).watermark(Positions.CENTER, waterImage, 0.5f).outputQuality(1.0f)
.toFile("images/image_watermark_center.jpg");

/*
* 裁剪
* sourceRegion(位置,长,宽)
* sourceRegion(起始x坐标, 起始y坐标,长,宽)
*/
Thumbnails.of(originalImage).sourceRegion(Positions.TOP_LEFT, 400, 400).scale(1.0f)
.toFile("images/image_region_top_left.jpg");

Thumbnails.of(originalImage).sourceRegion(0, 0, 400, 400).size(200, 300).keepAspectRatio(true)
.toFile("images/image_region_0x0.jpg");

/*
* 指定输出格式
* outputFormat(图像格式)
*/
Thumbnails.of(originalImage).size(200, 300).outputFormat("png").toFile("images/image_200x300.png");

/*
* 输出到OutputStream
* toOutputStream(流对象)
*/
OutputStream os = new FileOutputStream("images/image_200x300_OutputStream.png");
Thumbnails.of(originalImage).size(200, 300).toOutputStream(os);

/*
* 输出到BufferedImage
* asBufferedImage()
*/
BufferedImage bf = Thumbnails.of(originalImage).size(200, 300).asBufferedImage();
ImageIO.write(bf, "jpg", new File("images/image_200x300_BufferedImage.jpg"));