Android Bitmap Android中的Bitmap的仔细讲解

  public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
    final int width = options.outWidth;
    final int height = options.outHeight;
    int inSampleSize = 1;
    
    if (width > reqWidth || height > reqHeight) {
      if (width > height) {
        inSampleSize = Math.round((float) height / (float) reqHeight);
      } else {
        inSampleSize = Math.round((float) width / (float) reqWidth);
      }
    }
    return inSampleSize;
  }

  public static Bitmap thumbnail(String path, int maxWidth, int maxHeight,boolean autoRotate) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    Bitmap bitmap = BitmapFactory.decodeFile(path);
    options.inJustDecodeBounds = false;
    int sampleSize = calculateInSampleSize(options,maxWidth,maxHeight);
    options.inSampleSize =sampleSize;
    options.inPreferredConfig = Bitmap.Config.RGB_565;
    options.inPurgeable =true;
    options.inInputShareable = true;
    if(bitmap !=null&&!bitmap.isRecycled()){
      bitmap.recycle();
    }
    bitmap = BitmapFactory.decodeFile(path,options);
    return bitmap;
  }

public static String save(Bitmap bitmap, Bitmap.CompressFormat format, int quality,File desFile) {
    try{
      FileOutputStream out = new FileOutputStream(desFile);
      if(bitmap.compress(format,quality,out)){
        out.flush();
        out.close();
      }
      if(bitmap!=null&&!bitmap.isRecycled()){
        bitmap.recycle();
      }
      return desFile.getAbsolutePath();
    }catch (FileNotFoundException e){
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return null;
  }

public static String save(Bitmap bitmap, Bitmap.CompressFormat format, int quality,Context context) {
    if(!Environment.getExternalStorageState()
        .equals(Environment.MEDIA_MOUNTED)){
      return null;
    }
    File dir = new File(Environment.getExternalStorageDirectory()+
    "/"+context.getPackageName());
    if(!dir.exists()){
      dir.mkdir();
    }
    File desFile = new File(dir, UUID.randomUUID().toString());
    return save(bitmap,format,quality,desFile);
  }

public static Bitmap compressImage(Bitmap image) {
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  // 把ByteArrayInputStream数据生成图片
  Bitmap bitmap = null;
  image.compress(Bitmap.CompressFormat.JPEG, 5, baos);
  byte[] bytes = baos.toByteArray();
  // 把压缩后的数据baos存放到bytes中
  bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
  if (bitmap != null) {
    loga(bitmap, baos.toByteArray());
  }
  return bitmap;
}

// 质量压缩方法，options的值是0-100，这里100表示原来图片的质量，不压缩，把压缩后的数据存放到baos中
image.compress(Bitmap.CompressFormat.JPEG, 100, baos);
int options = 90;
// 循环判断如果压缩后图片是否大于500kb,大于继续压缩
while (baos.toByteArray().length / 1024 > 100) {
  // 重置baos即清空baos
  baos.reset();
  // 这里压缩options%，把压缩后的数据存放到baos中
  image.compress(Bitmap.CompressFormat.JPEG, options, baos);
  // 每次都减少10
  if(options == 1){
    break;
  }else if (options <= 10) {
    options -= 1;
  } else {
    options -= 10;
  }
}

int inSampleSize = getScaling(bitmap); bitmap = samplingRateCompression(path,inSampleSize);
private Bitmap samplingRateCompression(String path, int scaling) {

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = scaling;

Bitmap bitmap = BitmapFactory.decodeFile(path, options);

int size = (bitmap.getByteCount() / 1024 / 1024);

Log.i("wechat", "压缩后图片的大小" + (bitmap.getByteCount() / 1024 / 1024)
    + "M宽度为" + bitmap.getWidth() + "高度为" + bitmap.getHeight());
return bitmap;
}

/**
* 获取缩放比例
* @param bitmap
* @return
*/
private int getScaling(Bitmap bitmap) {
  //设置目标尺寸（以像素的宽度为标准）
  int Targetsize = 1500;
  int width = bitmap.getWidth();
  int height = bitmap.getHeight();
  //选择最大值作为比较值（保证图片的压缩大小）
  int handleValue = width > height ? width : height;
  //循环计算压缩比
  int i = 1;
  while (handleValue / i > Targetsize) {
    i++;
  }
}

private Bitmap ScalingCompression(Bitmap bitmap) {
  Matrix matrix = new Matrix();
  matrix.setScale(0.25f, 0.25f);//缩放效果类似于方法2
  Bitmap bm = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),
    bitmap.getHeight(), matrix, true);
  Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024 / 1024)
    + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight());
  return bm;
}

private Bitmap bitmapConfig(String path) {
  BitmapFactory.Options options = new BitmapFactory.Options();
  options.inPreferredConfig = Bitmap.Config.RGB_565;

  Bitmap bm = BitmapFactory.decodeFile(path, options);
  Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024f / 1024f)
  + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight());
  return bm;
} 

Bitmap.createScaledBitmap(src, dstWidth, dstHeight, filter);

private Bitmap createScaledBitmap(Bitmap bitmap) {
  Bitmap bm = Bitmap.createScaledBitmap(bitmap, 200, 200, true);
  Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024) + "KB宽度为"
    + bm.getWidth() + "高度为" + bm.getHeight());
  return bm;
}

bitmap = BitmapFactory.decodeFile(path);

private Bitmap getBitmapByPath(String path) {
if (!new File(path).exists()) {
  System.err.println("getBitmapByPath: 文件不存在");
  return null;
}
byte[] buf = new byte[1024 * 1024];// 1M
Bitmap bitmap = null;
try {
  FileInputStream fis = new FileInputStream(path);
  int len = fis.read(buf, 0, buf.length);
  bitmap = BitmapFactory.decodeByteArray(buf, 0, len);
  //当bitmap为空的时候，说明解析失败
  if (bitmap == null) {
    System.out.println("文件长度:" + len);
    System.err.println("path: " + path + " 无法解析!!!");
  }
} catch (Exception e) {
  e.printStackTrace();
}
return bitmap;
}

private void savaPictrue(Bitmap bitmap) {
  File file = new File("storage/emulated/0/DCIM/Camera/test.jpg");
  FileOutputStream stream = null;
  try {
    stream = new FileOutputStream(file);
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
    Log.e("图片大小：", file.length() / 1024 / 1024 + "M");
  } catch (Exception e) {
    e.printStackTrace();
  }
}

private void crop(Uri uri) {
  // 裁剪图片意图
  Intent intent = new Intent("com.android.camera.action.CROP");
  intent.setDataAndType(uri, "image/*");
  intent.putExtra("crop", "true");
  // 裁剪框的比例，1：1
  intent.putExtra("aspectX", 1);
  intent.putExtra("aspectY", 1);
  // 裁剪后输出图片的尺寸大小
  intent.putExtra("outputX", 300);
  intent.putExtra("outputY", 300);

  intent.putExtra("outputFormat", "JPEG");// 图片格式
  intent.putExtra("noFaceDetection", true);// 取消人脸识别
  intent.putExtra("return-data", true);
  // 开启一个带有返回值的Activity，请求码为PHOTO_REQUEST_CUT
  startActivityForResult(intent, 200);
}

private void logp(Bitmap bitmap) {
Log.i("wechat", "压缩前图片的大小" + (bitmap.getByteCount() / 1024 / 1024)
    + "M宽度为" + bitmap.getWidth() + "高度为" + bitmap.getHeight());
}

private static void loga(Bitmap bitmap, byte[] bytes) {
  Log.i("wechat", "压缩后图片的大小" + (bitmap.getByteCount() / 1024 / 1024)
    + "M宽度为" + bitmap.getWidth() + "高度为" + bitmap.getHeight()
    + "bytes.length= " + (bytes.length / 1024) + "KB"
  );
}