Android 图片压缩，基于比例和质量压缩

package cc.util.android.image;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.BitmapFactory.Options;
import android.graphics.Matrix;
import android.media.ExifInterface;
import android.util.Log;

/**
* A class for helping deal the bitmap,
*  like: get the orientation of the bitmap, compress bitmap etc.
* @author wangcccong
* @version 1.140122
* crated at: 2014-03-22
* update at: 2014-06-26
*/
public class BitmapHelper {

/**
* get the orientation of the bitmap {@link android.media.ExifInterface}
* @param path
* @return
*/
public final static int getDegress(String path) {
int degree = 0;
try {
ExifInterface exifInterface = new ExifInterface(path);
int orientation = exifInterface.getAttributeInt(
ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
degree = 90;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
degree = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
degree = 270;
break;
}
} catch (IOException e) {
e.printStackTrace();
}
return degree;
}

/**
* rotate the bitmap
* @param bitmap
* @param degress
* @return
*/
public static Bitmap rotateBitmap(Bitmap bitmap, int degress) {
if (bitmap != null) {
Matrix m = new Matrix();
m.postRotate(degress);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), m, true);
return bitmap;
}
return bitmap;
}

/**
* caculate the bitmap sampleSize
* @param path
* @return
*/
public final static int caculateInSampleSize(BitmapFactory.Options options, int rqsW, int rqsH) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (rqsW == 0 || rqsH == 0) return 1;
if (height > rqsH || width > rqsW) {
final int heightRatio = Math.round((float) height/ (float) rqsH);
final int widthRatio = Math.round((float) width / (float) rqsW);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
}
return inSampleSize;
}

/**
* 压缩指定路径的图片，并得到图片对象
* @param context
* @param path bitmap source path
* @return Bitmap {@link android.graphics.Bitmap}
*/
public final static Bitmap compressBitmap(String path, int rqsW, int rqsH) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
options.inSampleSize = caculateInSampleSize(options, rqsW, rqsH);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(path, options);
}

/**
* 压缩指定路径图片，并将其保存在缓存目录中，通过isDelSrc判定是否删除源文件，并获取到缓存后的图片路径
* @param context
* @param srcPath
* @param rqsW
* @param rqsH
* @param isDelSrc
* @return
*/
public final static String compressBitmap(Context context, String srcPath, int rqsW, int rqsH, boolean isDelSrc) {
Bitmap bitmap = compressBitmap(srcPath, rqsW, rqsH);
File srcFile = new File(srcPath);
String desPath = getImageCacheDir(context) + srcFile.getName();
int degree = getDegress(srcPath);
try {
if (degree != 0) bitmap = rotateBitmap(bitmap, degree);
File file = new File(desPath);
FileOutputStream  fos = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 70, fos);
fos.close();
if (isDelSrc) srcFile.deleteOnExit();
} catch (Exception e) {
// TODO: handle exception
Log.e("BitmapHelper-->compressBitmap", e.getMessage()+"");
}
return desPath;
}

/**
* 此方法过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法
* @param is
* @param reqsW
* @param reqsH
* @param isAdjust
* @return
*/
@Deprecated
public final static Bitmap compressBitmap(InputStream is, int reqsW, int reqsH, boolean isAdjust) {
Bitmap bitmap = BitmapFactory.decodeStream(is);
return compressBitmap(bitmap, reqsW, reqsH, isAdjust);
}

/**
* 压缩某个输入流中的图片，可以解决网络输入流压缩问题，并得到图片对象
* @param context
* @param path bitmap source path
* @return Bitmap {@link android.graphics.Bitmap}
*/
public final static Bitmap compressBitmap(InputStream is, int reqsW, int reqsH) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ReadableByteChannel channel = Channels.newChannel(is);
ByteBuffer buffer = ByteBuffer.allocate(1024);
while (channel.read(buffer) != -1) {
buffer.flip();
while (buffer.hasRemaining()) baos.write(buffer.get());
buffer.clear();
}
byte[] bts = baos.toByteArray();
Bitmap bitmap = compressBitmap(bts, reqsW, reqsH);
is.close();
channel.close();
baos.close();
return bitmap;
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
return null;
}
}

/**
* 压缩指定byte[]图片，并得到压缩后的图像
* @param bts
* @param reqsW
* @param reqsH
* @return
*/
public final static Bitmap compressBitmap(byte[] bts, int reqsW, int reqsH) {
final Options options = new Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(bts, 0, bts.length, options);
options.inSampleSize = caculateInSampleSize(options, reqsW, reqsH);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeByteArray(bts, 0, bts.length, options);
}

/**
* 此方法已过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法
* @param bitmap
* @param reqsW
* @param reqsH
* @return
*/
@Deprecated
public final static Bitmap compressBitmap(Bitmap bitmap, int reqsW, int reqsH, boolean isAdjust) {
if (bitmap == null || reqsW == 0 || reqsH == 0) return bitmap;
if (bitmap.getWidth() > reqsW || bitmap.getHeight() > reqsH) {
float scaleX = new BigDecimal(reqsW).divide(new BigDecimal(bitmap.getWidth()), 4, RoundingMode.DOWN).floatValue();
float scaleY = new BigDecimal(reqsH).divide(new BigDecimal(bitmap.getHeight()), 4, RoundingMode.DOWN).floatValue();
if (isAdjust) {
scaleX = scaleX < scaleY ? scaleX : scaleY;
scaleY = scaleX;
}
Matrix matrix = new Matrix();
matrix.postScale(scaleX, scaleY);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}
return bitmap;
}

/**
* 压缩已存在的图片对象，并返回压缩后的图片
* @param bitmap
* @param reqsW
* @param reqsH
* @return
*/
public final static Bitmap compressBitmap(Bitmap bitmap, int reqsW, int reqsH) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 100, baos);
byte[] bts = baos.toByteArray();
Bitmap res = compressBitmap(bts, reqsW, reqsH);
baos.close();
return res;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return bitmap;
}
}

/**
* 此方法过期，该方法可能造成OutOfMemoryError，使用不含isAdjust参数的方法
* get bitmap form resource dictory, and then compress bitmap according to reqsW and reqsH
* @param res {@link android.content.res.Resources}
* @param resID
* @param reqsW
* @param reqsH
* @return
*/
@Deprecated
public final static Bitmap compressBitmap(Resources res, int resID, int reqsW, int reqsH, boolean isAdjust) {
Bitmap bitmap = BitmapFactory.decodeResource(res, resID);
return compressBitmap(bitmap, reqsW, reqsH, isAdjust);
}

/**
* 压缩资源图片，并返回图片对象
* @param res {@link android.content.res.Resources}
* @param resID
* @param reqsW
* @param reqsH
* @return
*/
public final static Bitmap compressBitmap(Resources res, int resID, int reqsW, int reqsH) {
final Options options = new Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resID, options);
options.inSampleSize = caculateInSampleSize(options, reqsW, reqsH);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resID, options);
}

/**
* 基于质量的压缩算法， 此方法未 解决压缩后图像失真问题
* <br> 可先调用比例压缩适当压缩图片后，再调用此方法可解决上述问题
* @param bts
* @param maxBytes 压缩后的图像最大大小 单位为byte
* @return
*/
public final static Bitmap compressBitmap(Bitmap bitmap, long maxBytes) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 100, baos);
int options = 90;
while (baos.toByteArray().length > maxBytes) {
baos.reset();
bitmap.compress(CompressFormat.PNG, options, baos);
options -= 10;
}
byte[] bts = baos.toByteArray();
Bitmap bmp = BitmapFactory.decodeByteArray(bts, 0, bts.length);
baos.close();
return bmp;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}

//  public final static Bitmap compressBitmap(InputStream is, long maxBytes) {
//      try {
//          ByteArrayOutputStream baos = new ByteArrayOutputStream();
//          byte[] bts = new byte[1024];
//          while (is.read(bts) != -1) baos.write(bts, 0, bts.length);
//          is.close();
//          int options = 100;
//          while (baos.toByteArray().length > maxBytes) {
//
//          }
//      } catch (Exception e) {
//          // TODO: handle exception
//      }
//  }

/**
* 得到指定路径图片的options
* @param srcPath
* @return Options {@link android.graphics.BitmapFactory.Options}
*/
public final static Options getBitmapOptions(String srcPath) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(srcPath, options);
return options;
}

/**
* 获取图片缓存路径
* @param context
* @return
*/
private static String getImageCacheDir(Context context) {
String dir = FileHelper.getCacheDir(context) + "Image" + File.separator;
File file = new File(dir);
if (!file.exists()) file.mkdirs();
return dir;
}
}