图片缩放
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2022-03-16 15:16:08
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/**
* 通过传进来的二进制图片流,将图片缩放后返回,用于文件上传取得缩放图,然后存数据库
*
* @param bt
* 原图二进制
* @param targetW
* 目标宽度
* @param targetH
* 目标长度
* @return 缩放后图片的二进制
* @throws IOException
* 流读写异常
*/
public static byte[] resize(byte[] bt, Integer targetW, Integer targetH)
throws IOException {
ByteArrayInputStream bai = new java.io.ByteArrayInputStream(bt);
BufferedImage bimg = javax.imageio.ImageIO.read(bai);
BufferedImage target = resize(bimg, targetW, targetH);
ByteArrayOutputStream os = new ByteArrayOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);
encoder.encode(target);
byte[] arr = os.toByteArray();
os.flush();
os.close();
bai.close();
return arr;
}
昨天做的一个图片缩放,能够将上传的文件进行缩放后返回字节数组,然后存放数据库或其它操作。
public static BufferedImage resize(BufferedImage source, int targetW,
int targetH) throws IOException {
// targetW,targetH分别表示目标长和宽
int type = source.getType();
BufferedImage target = null;
double sx = (double) targetW / source.getWidth();
double sy = (double) targetH / source.getHeight();
// 这里想实现在targetW,targetH范围内实现等比缩放。如果不需要等比缩放
// 则将下面的if else语句注释即可
if (sx > sy) {
sx = sy;
targetW = (int) (sx * source.getWidth());
} else {
sy = sx;
targetH = (int) (sy * source.getHeight());
}
if (type == BufferedImage.TYPE_CUSTOM) {
ColorModel cm = source.getColorModel();
WritableRaster raster = cm.createCompatibleWritableRaster(targetW,
targetH);
boolean alphaPremultiplied = cm.isAlphaPremultiplied();
target = new BufferedImage(cm, raster, alphaPremultiplied, null);
} else
target = new BufferedImage(targetW, targetH, type);
Graphics2D g = target.createGraphics();
g.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
g.dispose();
return target;
}