Question

I have this code:

//choosed a picture
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (resultCode == RESULT_OK) {
        if (requestCode == ImageHelper.SELECT_PICTURE) {

            String picture           = "";

            Uri selectedImageUri     = data.getData();
            //OI FILE Manager
            String filemanagerstring = selectedImageUri.getPath();
            //MEDIA GALLERY
            String selectedImagePath = ImageHelper.getPath(mycontext, selectedImageUri);

            picture=(selectedImagePath!=null)?selectedImagePath:filemanagerstring;

…

This is only a picture chooser, from gallery. This is nice, but when I open this picture on an ImageView, the images when took on “PORTRAIT MODE” with the camera look nice, but the images that took “LANDSCAPE MODE” with the camera, opening in -90 degrees.

How can i rotate those pictures back?

    Bitmap output       = Bitmap.createBitmap(newwidth, newheight, Config.ARGB_8888);
    Canvas canvas       = new Canvas(output);

I tried this:

Log.e("w h", bitmap.getWidth()+" "+bitmap.getHeight());
if (bitmap.getWidth()<bitmap.getHeight()) canvas.rotate(-90);

But this is not working, all image size is: *2560 1920 pixel (PORTRAIT, and LANDSCAPE mode all)

What can I do to rotate back the LANDSCAPE pictures?

Answer 1

If a photo is taken with a digital camera or smartphone, rotation is often stored in the photo’s Exif data, as part of the image file. You can read an image’s Exif meta-data using the Android ExifInterface.

First, create the ExifInterface:

ExifInterface exif = new ExifInterface(uri.getPath());

Next, find the current rotation:

int rotation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);  

Convert exif rotation to degrees:

int rotationInDegrees = exifToDegrees(rotation);

where

private static int exifToDegrees(int exifOrientation) {        
    if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_90) { return 90; } 
    else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_180) {  return 180; } 
    else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_270) {  return 270; }            
    return 0;    
 }

Then use the image’s actual rotation as a reference point to rotate the image using a Matrix.

Matrix matrix = new Matrix();
if (rotation != 0) {matrix.preRotate(rotationInDegrees);}

You create the new rotated image with the Bitmap.createBitmap method that take a Matrix as a parameter:

Bitmap.createBitmap(Bitmap source, int x, int y, int width, int height, Matrix m, boolean filter)

where Matrix m holds the new rotation:

Bitmap adjustedBitmap = Bitmap.createBitmap(sourceBitmap, 0, 0, width, height, matrix, true);

See this tutorial for a useful source code example:

• Read Exif information in a JPEG file.