Android Get Orientation Of A Camera Bitmap? And Rotate Back -90 Degrees


Answer :

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.

Last answer was technically perfect, but I tried hard to create a system to manage pictures, rotate, resize, cache and load into ImageViews and I can tell it is a hell. Even when all it was done it crashes sometimes cause OutOfMemory in some devices.

My point is do not reinvent the wheel, it has a perfect design. Google itself encourage you to use Glide. It works in one line, super easy to use, lightweight in size and functions number, it manage EXIF by default, and it use memory like a charm.. It is simply black magic coded ;)

I'm not sure if Picasso also manages EXIF, but there is a quick intro to both of them:

https://inthecheesefactory.com/blog/get-to-know-glide-recommended-by-google/en

My Advice: do not waste your time and use them. You can solve your problem in one line:

Glide.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);

if you are Using Jetpack CameraX, inside onImageCaptured method you can access rotation degree provided by EXIF data from the imageProxy like this:

image.imageInfo.rotationDegrees

then while setting your image you can rotate your image according to this degree


Comments

Post a Comment

Popular posts from this blog

Converting A String To Int In Groovy

Answer : Use the toInteger() method to convert a String to an Integer , e.g. int value = "99".toInteger() An alternative, which avoids using a deprecated method (see below) is int value = "66" as Integer If you need to check whether the String can be converted before performing the conversion, use String number = "66" if (number.isInteger()) { int value = number as Integer } Deprecation Update In recent versions of Groovy one of the toInteger() methods has been deprecated. The following is taken from org.codehaus.groovy.runtime.StringGroovyMethods in Groovy 2.4.4 /** * Parse a CharSequence into an Integer * * @param self a CharSequence * @return an Integer * @since 1.8.2 */ public static Integer toInteger(CharSequence self) { return Integer.valueOf(self.toString().trim()); } /** * @deprecated Use the CharSequence version * @see #toInteger(CharSequence) */ @Deprecated public static Integer toInteger(String self) { return toInteg
Read more

"Cannot Create Cache Directory /home//.composer/cache/repo/https---packagist.org/, Or Directory Is Not Writable. Proceeding Without Cache"

Answer : if anyone pass through here, this is shorter solution: sudo chown -R $USER $HOME/.composer it seems to me the group information is missing in your command sudo chown -R <user> /home/<user>/.composer/cache/repo/https---packagist.org Shoud be sudo chown -R <user>:<group> /home/<user>/.composer/cache/repo/https---packagist.org But to avoid other permission issues, I would rather advise: sudo chown -R <user>:<group> /home/<user>/.composer/cache (you'll need access to other folders in there) and sudo chown <user>:<group> /home/<user>/.composer To make sure your user has permissions enough on the global composer folder. Mind the missing recursion so the user don't own keys created by root. If you need to find out the group: groups <user>
Read more

Android How Can I Convert A String To A Editable

Answer : As you probably found out, Editable is an interface so you cannot call new Editable() . However an Editable is nothing more than a String with Spannables, so use SpannableStringBuilder: Editable editable = new SpannableStringBuilder("Pass a string here"); If you only want to change the Spannables, never the text itself, you can use a basic SpannableString. Use Editable.Factory.getInstance().newEditable(str) From the android documentation: Returns a new SpannedStringBuilder from the specified CharSequence. You can override this to provide a different kind of Spanned.
Read more