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  • Android 下压缩图片—微弱失真

    Android下压缩图片的方法:

    大概能将3M左右的图片压缩到100K左右, 几乎不失真。 代码如下:

    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.OutputStream;
    
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    
    public class BitmapUtil {
        /**
         * 压缩图片之后保存为文件
         * 
         * @param filePath
         *            原始图片的完整路径
         * @param storeImgPath
         *            压缩之后要存储的图片的完整路径
         * @return boolean
         * @author Doraemon
         * @time 2014年6月27日下午5:10:19
         */
        public static boolean saveCompressImg(String filePath, String storeImgPath) {
            Bitmap bm = getSmallBitmap(filePath);
            OutputStream stream = null;
            try {
                stream = new FileOutputStream(storeImgPath);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
    
            return bm.compress(Bitmap.CompressFormat.JPEG, 40, stream);
        }
    
        /**
         * 根据路径获得突破并压缩返回bitmap用于显示
         * 
         * @param imagesrc
         * @return
         */
        private static Bitmap getSmallBitmap(String filePath) {
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(filePath, options);
    
            // Calculate inSampleSize
            options.inSampleSize = calculateInSampleSize(options, 480, 800);
    
            // Decode bitmap with inSampleSize set
            options.inJustDecodeBounds = false;
    
            return BitmapFactory.decodeFile(filePath, options);
        }
    
        /**
         * 计算图片的缩放值
         * 
         * @param options
         * @param reqWidth
         * @param reqHeight
         * @return
         */
        private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
            // Raw height and width of image
            final int height = options.outHeight;
            final int width = options.outWidth;
            int inSampleSize = 1;
    
            if (height > reqHeight || width > reqWidth) {
    
                // Calculate ratios of height and width to requested height and
                // width
                final int heightRatio = Math.round((float) height / (float) reqHeight);
                final int widthRatio = Math.round((float) width / (float) reqWidth);
    
                // Choose the smallest ratio as inSampleSize value, this will
                // guarantee
                // a final image with both dimensions larger than or equal to the
                // requested height and width.
                inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
            }
    
            return inSampleSize;
        }
    }
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  • 原文地址:https://www.cnblogs.com/hsx514/p/3821336.html
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