Java 图片等比缩放

需求

Java图片等比缩放，通过jdk自带的Graphics 实现对图片的等比缩放

示例

        //重置大小（太宽没啥用）最大支持1.5倍图（1150*1.5）
        int maxWidth=(int)(920*1.5);
        //大小重置
        //图片大小
        BufferedImage read = ImageIO.read(new ByteArrayInputStream(imageFileBytes));
        int width = read.getWidth();
        int height = read.getHeight();
        if (width>maxWidth){
            int dHeight = new BigDecimal(height).divide(new BigDecimal(width).divide(new BigDecimal(maxWidth), 2, RoundingMode.HALF_UP), 2, RoundingMode.HALF_UP).intValue();
            BufferedImage resizeImage=new BufferedImage(maxWidth,dHeight,BufferedImage.TYPE_INT_RGB);
            Graphics graphics = resizeImage.getGraphics();
            graphics.drawImage(read,0,0, maxWidth,dHeight,null);
            graphics.dispose();
            //重置大小
            ByteArrayOutputStream bos=new ByteArrayOutputStream();
            ImageIO.write(resizeImage,format.substring(1),bos);
            imageFileBytes=bos.toByteArray();
        }

over

Java图片缩放 Java图片等比缩放 图片缩放

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