CameraUtils for decoding bitmaps in background, ExifInterface library

README.md

@@ -57,11 +57,11 @@ CameraKit is an easy to use utility to work with the Android Camera APIs. Everyt
   - While taking pictures, image is captured normally using the camera APIs.
   - While shooting videos, image is captured as a freeze frame of the `CameraView` preview (similar to SnapChat and Instagram)
 - Built-in tap to focus
+- `CameraUtils` to help with Bitmaps and orientations
 - EXIF support
   - Automatically detected orientation tag
   - Plug in location tags with `CameraView.setLocation(double, double)`
-- Control the camera parameters via XML or programmatically  
-- TODO: Built-in pinch to zoom
+- Control the camera parameters via XML or programmatically
 
 ## Setup
 
@@ -109,7 +109,8 @@ camera.setCameraListener(new CameraListener() {
     @Override
     public void onPictureTaken(byte[] picture) {
         // Create a bitmap or a file...
-        Bitmap result = BitmapFactory.decodeByteArray(picture, 0, picture.length);
+        // CameraUtils will read EXIF orientation for you.
+        CameraUtils.decodeBitmap(picture, ...);
     }
 });
 
@@ -376,7 +377,7 @@ The library manifest file is not strict and only asks for camera permissions. Th
     android:required="true"/>
 ```
 
-If you don't request this feature, you can use `CameraKit.hasCameras()` to detect if current device has cameras, and then start the camera view.
+If you don't request this feature, you can use `CameraUtils.hasCameras()` to detect if current device has cameras, and then start the camera view.
 
 ## Roadmap
 

camerakit/build.gradle

@@ -32,9 +32,8 @@ android {
 }
 
 dependencies {
-    compile 'com.android.support:appcompat-v7:25.2.0'
-
-
+    compile 'com.android.support:appcompat-v7:25.3.1'
+    compile 'com.android.support:exifinterface:25.3.1'
     compile 'android.arch.lifecycle:runtime:1.0.0-alpha1'
     compile 'android.arch.lifecycle:extensions:1.0.0-alpha1'
     annotationProcessor 'android.arch.lifecycle:compiler:1.0.0-alpha1'

camerakit/src/main/java/com/flurgle/camerakit/CameraKit.java

@@ -5,12 +5,6 @@ import android.content.pm.PackageManager;
 
 public class CameraKit {
 
-    public static boolean hasCameras(Context context) {
-        PackageManager manager = context.getPackageManager();
-        // There's also FEATURE_CAMERA_EXTERNAL , should we support it?
-        return manager.hasSystemFeature(PackageManager.FEATURE_CAMERA)
-                || manager.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT);
-    }
 
     public static class Constants {
 

camerakit/src/main/java/com/flurgle/camerakit/CameraUtils.java

@@ -0,0 +1,107 @@
+package com.flurgle.camerakit;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Matrix;
+import android.os.Handler;
+import android.support.media.ExifInterface;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Static utilities for dealing with camera I/O, orientation, etc.
+ */
+public class CameraUtils {
+
+
+    /**
+     * Determines whether the device has valid camera sensors, so the library
+     * can be used.
+     *
+     * @param context a valid Context
+     * @return whether device has cameras
+     */
+    public static boolean hasCameras(Context context) {
+        PackageManager manager = context.getPackageManager();
+        // There's also FEATURE_CAMERA_EXTERNAL , should we support it?
+        return manager.hasSystemFeature(PackageManager.FEATURE_CAMERA)
+                || manager.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT);
+    }
+
+
+    /**
+     * Decodes an input byte array and outputs a Bitmap that is ready to be displayed.
+     * The difference with {@link android.graphics.BitmapFactory#decodeByteArray(byte[], int, int)}
+     * is that this cares about orientation, reading it from the EXIF header.
+     * This is executed in a background thread, and returns the result to the original thread.
+     *
+     * This ignores flipping at the moment.
+     * TODO care about flipping using Matrix.scale()
+     *
+     * @param source a JPEG byte array
+     * @param callback a callback to be notified
+     */
+    public static void decodeBitmap(final byte[] source, final BitmapCallback callback) {
+        final Handler ui = new Handler();
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+
+                int orientation = 0;
+                try {
+                    // http://sylvana.net/jpegcrop/exif_orientation.html
+                    ExifInterface exif = new ExifInterface(new ByteArrayInputStream(source));
+                    Integer exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
+                    switch (exifOrientation) {
+                        case ExifInterface.ORIENTATION_NORMAL:
+                        case ExifInterface.ORIENTATION_FLIP_HORIZONTAL:
+                            orientation = 0; break;
+
+                        case ExifInterface.ORIENTATION_ROTATE_180:
+                        case ExifInterface.ORIENTATION_FLIP_VERTICAL:
+                            orientation = 180; break;
+
+                        case ExifInterface.ORIENTATION_ROTATE_90:
+                        case ExifInterface.ORIENTATION_TRANSPOSE:
+                            orientation = 90; break;
+
+                        case ExifInterface.ORIENTATION_ROTATE_270:
+                        case ExifInterface.ORIENTATION_TRANSVERSE:
+                            orientation = 270; break;
+
+                        default: orientation = 0;
+                    }
+                } catch (IOException e) {
+                    e.printStackTrace();
+                    orientation = 0;
+                }
+
+
+                Bitmap bitmap = BitmapFactory.decodeByteArray(source, 0, source.length);
+                if (orientation != 0) {
+                    Matrix matrix = new Matrix();
+                    matrix.setRotate(orientation);
+                    Bitmap temp = bitmap;
+                    bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
+                    temp.recycle();
+                }
+                final Bitmap result = bitmap;
+                ui.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        callback.onBitmapReady(result);
+                    }
+                });
+            }
+        }).start();
+    }
+
+
+    public interface BitmapCallback {
+        void onBitmapReady(Bitmap bitmap);
+    }
+}