Question

我在onPictureTaken中发现保存的位图是围绕y轴镜像的，并且顺时针旋转了90度，即使相机预览没有。这是在我的Nexus S上运行2.3.6。在带有4.2的Nexus 4上运行的相同程序生成的位图围绕y轴镜像，并顺时针旋转180度。

这是我在onPictureTaken中运行的代码：

@Override
public void onPictureTaken(final byte[] data, Camera camera) {
    Bitmap picture = BitmapFactory.decodeByteArray(data, 0, data.length);
    String path = MediaStore.Images.Media.insertImage(getContentResolver(), picture, "name" , "description");
    Log.e("tag", "path: " + path); // prints something like "path: content://media/external/images/media/819"

    try {
        ExifInterface exif = new ExifInterface(path); // prints this error: "04-25 21:28:21.063: E/JHEAD(12201): can't open 'content://media/external/images/media/819'"
        int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
        Log.e("tag", "exif orientation: " + orientation); // this is outputting orientation unknown
    } catch (IOException e) {
        e.printStackTrace();
    }
}

任何人都可以告诉我如何纠正这一点，因为我似乎从不同的设备获得了不同的结果？如何检测结果位图的方向，以便我知道逆时针旋转90度或180度？

[编辑]

我使用我一直在阅读的ExifInterface内容添加了一些更多信息，但这些信息似乎没有显示出来......

Answer 1

我已经做了很多工作并想到了，我会分享我的解决方案。它在摩托罗拉Devy，三星Xcover 1和三星XCover 2上进行了测试。

当我使用自定义相机预览时，解决方案基本上有两个部分。 1.照顾相机预览并根据预设设置旋转设备轮换。 2.一旦拍照，即调用'onPictureTaken'回调以正确的角度旋转图片，以便显示预览的内容显示。

1

private void initPreview(int width, int height) {
    if (camera != null && holder.getSurface() != null) {
        try {
            camera.setPreviewDisplay(holder);
        } catch (Throwable t) {
            Log.e("PreviewDemo-surfaceCallback",
              "Exception in setPreviewDisplay()", t);
            Toast.makeText(getContext(), t.getMessage(),
                       Toast.LENGTH_LONG).show();
        }

        try {
            Camera.Parameters parameters=camera.getParameters();

            Camera.Size size=getBestPreviewSize(width, height, parameters);
            Camera.Size pictureSize=getSmallestPictureSize(parameters);

            Display display = windowManager.getDefaultDisplay();
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.FROYO) { // for 2.1 and before
                if (isPortrait(display)) {
                    parameters.set(CAMERA_PARAM_ORIENTATION, CAMERA_PARAM_PORTRAIT);
                } else {
                    parameters.set(CAMERA_PARAM_ORIENTATION, CAMERA_PARAM_LANDSCAPE);
                }
            } else { // for 2.2 and later
                switch (display.getRotation()) {
                    case Surface.ROTATION_0: // This is display orientation
                        if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
                        else parameters.setPreviewSize(size.width, size.height);
                        camera.setDisplayOrientation(90);
                        break;
                    case Surface.ROTATION_90:
                        if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
                        else parameters.setPreviewSize(size.width, size.height);
                        camera.setDisplayOrientation(0);
                        break;
                    case Surface.ROTATION_180:
                        if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
                        else parameters.setPreviewSize(size.width, size.height);
                        camera.setDisplayOrientation(270);
                        break;
                    case Surface.ROTATION_270:
                        if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
                        else parameters.setPreviewSize(size.width, size.height);
                        camera.setDisplayOrientation(180);
                        break;
                }
            }

            parameters.setPictureSize(pictureSize.width, pictureSize.height);
            //parameters.setPictureFormat(ImageFormat.JPEG);
            camera.setParameters(parameters);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

您的'surfaceChanged'方法，在相机预览（SurfaceView）中，你应该看起来像这样：

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        stopPreview();
        initPreview(w, h);
        startPreview();
    }

其中

stopPreview：

private void stopPreview() {
    if (camera != null) {
        camera.stopPreview();
    }
}

startPreview：

private void startPreview() {
    if (camera != null) {
        camera.startPreview();
    }
}

2

在'onPictureTaken'回调中，使用以下代码旋转图片：

Display display = getWindowManager().getDefaultDisplay();
    int rotation = 0;
    switch (display.getRotation()) {
        case Surface.ROTATION_0: // This is display orientation
        rotation = 90;
        break;
    case Surface.ROTATION_90:
        rotation = 0;
        break;
    case Surface.ROTATION_180:
        rotation = 270;
        break;
    case Surface.ROTATION_270:
        rotation = 180;
            break;
     }

     Bitmap bitmap = BitmapTools.toBitmap(data);
     bitmap = BitmapTools.rotate(bitmap, rotation);

BitmapTools.java

public class BitmapTools {

        public static Bitmap toBitmap(byte[] data) {
            return BitmapFactory.decodeByteArray(data , 0, data.length);
        }

        public static Bitmap rotate(Bitmap in, int angle) {
            Matrix mat = new Matrix();
            mat.postRotate(angle);
            return Bitmap.createBitmap(in, 0, 0, in.getWidth(), in.getHeight(), mat, true);
        }
    }

Answer 2

在这里你去检查一下，保存图片，也许这会工作并记住if（bitmap.getWidth＆gt; bitmap.getHeight（））作为另一个检查

public static int getExifRotation(String imgPath) 
    {
        try 
        {
            ExifInterface exif = new ExifInterface(imgPath);
            String rotationAmount = exif.getAttribute(ExifInterface.TAG_ORIENTATION);
            if (!TextUtils.isEmpty(rotationAmount)) 
            {
                int rotationParam = Integer.parseInt(rotationAmount);
                switch (rotationParam) 
                {
                    case ExifInterface.ORIENTATION_NORMAL:
                        return 0;
                    case ExifInterface.ORIENTATION_ROTATE_90:
                        return 90;
                    case ExifInterface.ORIENTATION_ROTATE_180:
                        return 180;
                    case ExifInterface.ORIENTATION_ROTATE_270:
                        return 270;
                    default:
                        return 0;
                }
            } 
            else 
            {
                return 0;
            }
        }
        catch (Exception ex) 
        {
            return 0;
        }
    }

Answer 3

您必须阅读ExifInterface才能解决此问题。

我在我的应用程序中有这个功能来检查从摄像机拍摄的天气天气图像是否需要旋转。

      if(ExifNeedsRotate(GetPathFromUri(context, selectedImage))){
    // Rotate your bitmap using the Matrix
     }


public static boolean ExifNeedsRotate(String paramString){

      if (android.os.Build.VERSION.SDK_INT >= 5){

          try
          {

                Class localClass = Class.forName("android.media.ExifInterface");
                Class[] arrayOfClass1 = new Class[1];
                arrayOfClass1[0] = String.class;
                Constructor localConstructor = localClass.getConstructor(arrayOfClass1);
                Class[] arrayOfClass2 = new Class[1];
                arrayOfClass2[0] = String.class;
                Method localMethod = localClass.getMethod("getAttribute", arrayOfClass2);
                Object[] arrayOfObject1 = new Object[1];
                arrayOfObject1[0] = paramString;
                Object localObject1 = localConstructor.newInstance(arrayOfObject1);
                Object[] arrayOfObject2 = new Object[1];
                arrayOfObject2[0] = "Orientation";
                Object localObject2 = localMethod.invoke(localObject1, arrayOfObject2);
                if (localObject2 != null){
                      boolean bool = localObject2.equals("6");
                      if (bool)
                         return true;
                }

          }
          catch (Exception localException){
              return false;
          }

    }

    return false;

}

将ImageUri的路径作为输入传递。

 public static String GetPathFromUri(Context paramContext, Uri paramUri)
  {
       String str;
       try
       {
            if (paramUri.toString().startsWith("file:")){
                    str = paramUri.getPath();
            }
            else
            {
                    str = null;
                    String[] arrayOfString = new String[1];
                    arrayOfString[0] = "_data";
                    Cursor localCursor = paramContext.getContentResolver().query(paramUri, arrayOfString, null, null, null);
                    if (localCursor != null)
                    {
                            localCursor.moveToFirst();
                            int i = localCursor.getColumnIndex(arrayOfString[0]);
                            if ((localCursor.getCount() >= 1) && (localCursor.getColumnCount() >= i + 1))
                                str = localCursor.getString(i);
                            localCursor.close();
                    }
            }

      }
      catch (Exception localException){
          str = null;
      }

      return str;
  }

Answer 4

您可以将摄像头配置为在拍摄照片时为您旋转照片，而不是在拍摄的照片回调中显式旋转照片。

camera.SetDisplayOrientation(degrees) //sets the orientation in the preview

同时

cameraParameters.SetRotation(degress) //rotates the actual captured image

如何在onPictureTaken中旋转和翻转位图

4 个答案:

1

2