Android位圖從畫布或從BitmapFactory.createBitmap（src，x，y，w，h）繪製不正確

Question

在Android上，我試圖將從相機拍攝的圖像位圖裁剪爲固定的寬度/寬度，但是當我創建裁剪後的圖像時，結果始終會旋轉（即使沒有定義矩陣），請參閱http://i.imgur.com/MppWH69l.png 原始圖像和http://i.imgur.com/C4WVtwZl.png作爲裁剪後的圖像，該圖像被旋轉並顯示不正確。

爲什麼createBitmap方法旋轉要在目標位圖中繪製的位圖。

相關代碼如下

try {  int dstWidth = params[0].intValue(); 
      int dstHeight = params[1].intValue(); 
      int targetSize = Math.min(dstWidth, dstHeight); 
      BitmapFactory.Options options = new BitmapFactory.Options(); 
      options.inJustDecodeBounds = true; 
      BitmapFactory.decodeStream(getActivity().getContentResolver().openInputStream(mPhotoUri), null, options); 
//calculate min inSampleSize for avoiding memory problems 
      options.inSampleSize = calculateImageInSampleSize(options, targetSize, targetSize); 
      options.inJustDecodeBounds = false; 
      Bitmap originalPhotoBitmap = BitmapFactory.decodeStream(getActivity().getContentResolver() 
        .openInputStream(mPhotoUri), null, options); 
      mOriginalBitmap = Bitmap.createBitmap(originalPhotoBitmap, originalPhotoBitmap.getWidth() - targetSize, 
                 originalPhotoBitmap.getHeight() - targetSize, targetSize, targetSize); 
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } 

//codefor inSampleSize calculation from http://developer.android.com/training/displaying-bitmaps/load-bitmap.html#load-bitmap 

private int calculateImageInSampleSize(BitmapFactory.Options originalSize, int targetWidth, int targetHeight) { 
    final int width = originalSize.outWidth; 
    final int height = originalSize.outHeight; 
    int inSampleSize = 1; 

    if (height > targetHeight || width > targetWidth) { 
     final int halfHeight = height /2; 
     final int halfWidth = width /2; 

     while ((halfHeight /inSampleSize) > targetHeight && 
       (halfWidth/inSampleSize) > targetWidth) { 
      inSampleSize *= 2; 
     } 
    } 

    return inSampleSize; 
} 

Answer 1

每個設備遵循相機不同的方向，使你遵循這個例子解決您的問題

private Bitmap imageRotating(String filePath){ 
    try{ 
     ExifInterface exif = new ExifInterface(filePath); 
     int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED); 

     return rotateBitmap(decodeSampledBitmapFromResource(filePath,150,224), orientation); 
    } 
    catch(Exception e){ 
     e.printStackTrace(); 
     return null; 
    } 
} 

public static Bitmap rotateBitmap(Bitmap bitmap, int orientation) { 

    try{ 
     Matrix matrix = new Matrix(); 
     switch (orientation) { 
      case ExifInterface.ORIENTATION_NORMAL: 
       return bitmap; 
      case ExifInterface.ORIENTATION_FLIP_HORIZONTAL: 
       matrix.setScale(-1, 1); 
       break; 
      case ExifInterface.ORIENTATION_ROTATE_180: 
       matrix.setRotate(180); 
       break; 
      case ExifInterface.ORIENTATION_FLIP_VERTICAL: 
       matrix.setRotate(180); 
       matrix.postScale(-1, 1); 
       break; 
      case ExifInterface.ORIENTATION_TRANSPOSE: 
       matrix.setRotate(90); 
       matrix.postScale(-1, 1); 
       break; 
      case ExifInterface.ORIENTATION_ROTATE_90: 
       matrix.setRotate(90); 
       break; 
      case ExifInterface.ORIENTATION_TRANSVERSE: 
       matrix.setRotate(-90); 
       matrix.postScale(-1, 1); 
       break; 
      case ExifInterface.ORIENTATION_ROTATE_270: 
       matrix.setRotate(-90); 
       break; 
      default: 
       return bitmap; 
     } 
     try { 
      Bitmap bmRotated = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true); 
      bitmap.recycle(); 
      return bmRotated; 
     } 
     catch (OutOfMemoryError e) { 
      e.printStackTrace(); 
      return null; 
     } 
    } 
    catch (Exception e) { 
     e.printStackTrace(); 
     return null; 
    } 
}