Improve CameraUtils.decodeBitmap (#83)

cameraview/src/androidTest/java/com/otaliastudios/cameraview/CameraUtilsTest.java

@@ -36,15 +36,17 @@ public class CameraUtilsTest extends BaseTest {
         assertFalse(CameraUtils.hasCameras(context));
     }
 
-    @Test
-    public void testDecodeBitmap() {
-        int w = 100, h = 200, color = Color.WHITE;
-        Bitmap source = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
-        source.setPixel(0, 0, color);
-        final ByteArrayOutputStream os = new ByteArrayOutputStream();
+    // Encodes bitmap and decodes again using our utility.
+    private Task<Bitmap> encodeDecodeTask(Bitmap source) {
+        return encodeDecodeTask(source, 0, 0);
+    }
 
+    // Encodes bitmap and decodes again using our utility.
+    private Task<Bitmap> encodeDecodeTask(Bitmap source, final int maxWidth, final int maxHeight) {
+        final ByteArrayOutputStream os = new ByteArrayOutputStream();
         // Using lossy JPG we can't have strict comparison of values after compression.
         source.compress(Bitmap.CompressFormat.PNG, 100, os);
+        final byte[] data = os.toByteArray();
 
         final Task<Bitmap> decode = new Task<>();
         decode.listen();
@@ -59,9 +61,23 @@ public class CameraUtilsTest extends BaseTest {
         ui(new Runnable() {
             @Override
             public void run() {
-                CameraUtils.decodeBitmap(os.toByteArray(), callback);
+                if (maxWidth > 0 && maxHeight > 0) {
+                    CameraUtils.decodeBitmap(data, maxWidth, maxHeight, callback);
+                } else {
+                    CameraUtils.decodeBitmap(data, callback);
+                }
             }
         });
+        return decode;
+    }
+
+    @Test
+    public void testDecodeBitmap() {
+        int w = 100, h = 200, color = Color.WHITE;
+        Bitmap source = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
+        source.setPixel(0, 0, color);
+
+        Task<Bitmap> decode = encodeDecodeTask(source);
         Bitmap other = decode.await(800);
         assertNotNull(other);
         assertEquals(100, w);
@@ -73,4 +89,31 @@ public class CameraUtilsTest extends BaseTest {
 
         // TODO: improve when we add EXIF writing to byte arrays
     }
+
+
+    @Test
+    public void testDecodeDownscaledBitmap() {
+        int width = 1000, height = 2000;
+        Bitmap source = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
+        Task<Bitmap> task;
+        Bitmap other;
+
+        task = encodeDecodeTask(source, 100, 100);
+        other = task.await(800);
+        assertNotNull(other);
+        assertTrue(other.getWidth() <= 100);
+        assertTrue(other.getHeight() <= 100);
+
+        task = encodeDecodeTask(source, Integer.MAX_VALUE, Integer.MAX_VALUE);
+        other = task.await(800);
+        assertNotNull(other);
+        assertTrue(other.getWidth() == width);
+        assertTrue(other.getHeight() == height);
+
+        task = encodeDecodeTask(source, 6000, 6000);
+        other = task.await(800);
+        assertNotNull(other);
+        assertTrue(other.getWidth() == width);
+        assertTrue(other.getHeight() == height);
+    }
 }

cameraview/src/androidTest/java/com/otaliastudios/cameraview/IntegrationTest.java

@@ -459,7 +459,7 @@ public class IntegrationTest extends BaseTest {
         Size size = camera.getCaptureSize();
         camera.capturePicture();
         byte[] jpeg = waitForPicture(true);
-        Bitmap b = CameraUtils.decodeBitmap(jpeg);
+        Bitmap b = CameraUtils.decodeBitmap(jpeg, Integer.MAX_VALUE, Integer.MAX_VALUE);
         // Result can actually have swapped dimensions
         // Which one, depends on factors including device physical orientation
         assertTrue(b.getWidth() == size.getHeight() || b.getWidth() == size.getWidth());
@@ -497,7 +497,7 @@ public class IntegrationTest extends BaseTest {
         Size size = camera.getPreviewSize();
         camera.captureSnapshot();
         byte[] jpeg = waitForPicture(true);
-        Bitmap b = CameraUtils.decodeBitmap(jpeg);
+        Bitmap b = CameraUtils.decodeBitmap(jpeg, Integer.MAX_VALUE, Integer.MAX_VALUE);
         // Result can actually have swapped dimensions
         // Which one, depends on factors including device physical orientation
         assertTrue(b.getWidth() == size.getHeight() || b.getWidth() == size.getWidth());

cameraview/src/main/utils/com/otaliastudios/cameraview/CameraUtils.java

@@ -15,7 +15,7 @@ import java.io.IOException;
 import java.io.InputStream;
 
 /**
- * Static utilities for dealing with camera I/O, orientation, etc.
+ * Static utilities for dealing with camera I/O, orientations, etc.
  */
 public class CameraUtils {
 
@@ -27,6 +27,7 @@ public class CameraUtils {
      * @param context a valid Context
      * @return whether device has cameras
      */
+    @SuppressWarnings("WeakerAccess")
     public static boolean hasCameras(Context context) {
         PackageManager manager = context.getPackageManager();
         // There's also FEATURE_CAMERA_EXTERNAL , should we support it?
@@ -60,18 +61,34 @@ public class CameraUtils {
      * 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
      */
+    @SuppressWarnings("WeakerAccess")
     public static void decodeBitmap(final byte[] source, final BitmapCallback callback) {
+        decodeBitmap(source, Integer.MAX_VALUE, Integer.MAX_VALUE, callback);
+    }
+
+    /**
+     * 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.
+     *
+     * The image is also downscaled taking care of the maxWidth and maxHeight arguments.
+     *
+     * @param source a JPEG byte array
+     * @param maxWidth the max allowed width
+     * @param maxHeight the max allowed height
+     * @param callback a callback to be notified
+     */
+    @SuppressWarnings("WeakerAccess")
+    public static void decodeBitmap(final byte[] source, final int maxWidth, final int maxHeight, final BitmapCallback callback) {
         final Handler ui = new Handler();
         WorkerHandler.run(new Runnable() {
             @Override
             public void run() {
-                final Bitmap bitmap = decodeBitmap(source);
+                final Bitmap bitmap = decodeBitmap(source, maxWidth, maxHeight);
                 ui.post(new Runnable() {
                     @Override
                     public void run() {
@@ -83,7 +100,11 @@ public class CameraUtils {
     }
 
 
-    static Bitmap decodeBitmap(byte[] source) {
+    // TODO ignores flipping
+    @SuppressWarnings({"SuspiciousNameCombination", "WeakerAccess"})
+    /* for tests */ static Bitmap decodeBitmap(byte[] source, int maxWidth, int maxHeight) {
+        if (maxWidth <= 0) maxWidth = Integer.MAX_VALUE;
+        if (maxHeight <= 0) maxHeight = Integer.MAX_VALUE;
         int orientation;
         boolean flip;
         InputStream stream = null;
@@ -123,12 +144,30 @@ public class CameraUtils {
             flip = false;
         } finally {
             if (stream != null) {
-                try { stream.close(); } catch (Exception e) {}
+                try { stream.close(); } catch (Exception ignored) {}
             }
         }
 
+        Bitmap bitmap;
+        if (maxWidth < Integer.MAX_VALUE || maxHeight < Integer.MAX_VALUE) {
+            BitmapFactory.Options options = new BitmapFactory.Options();
+            options.inJustDecodeBounds = true;
+            BitmapFactory.decodeByteArray(source, 0, source.length, options);
+
+            int outHeight = options.outHeight;
+            int outWidth = options.outWidth;
+            if (orientation % 180 != 0) {
+                outHeight = options.outWidth;
+                outWidth = options.outHeight;
+            }
+
+            options.inSampleSize = computeSampleSize(outWidth, outHeight, maxWidth, maxHeight);
+            options.inJustDecodeBounds = false;
+            bitmap = BitmapFactory.decodeByteArray(source, 0, source.length, options);
+        } else {
+            bitmap = BitmapFactory.decodeByteArray(source, 0, source.length);
+        }
 
-        Bitmap bitmap = BitmapFactory.decodeByteArray(source, 0, source.length);
         if (orientation != 0 || flip) {
             Matrix matrix = new Matrix();
             matrix.setRotate(orientation);
@@ -141,7 +180,30 @@ public class CameraUtils {
     }
 
 
+    private static int computeSampleSize(int width, int height, int maxWidth, int maxHeight) {
+        // https://developer.android.com/topic/performance/graphics/load-bitmap.html
+        int inSampleSize = 1;
+        if (height > maxHeight || width > maxWidth) {
+            while ((height / inSampleSize) >= maxHeight
+                    || (width / inSampleSize) >= maxWidth) {
+                inSampleSize *= 2;
+            }
+        }
+        return inSampleSize;
+    }
+
+
+    /**
+     * Receives callbacks about a bitmap decoding operation.
+     */
     public interface BitmapCallback {
+
+        /**
+         * Notifies that the bitmap was succesfully decoded.
+         * This is run on the UI thread.
+         *
+         * @param bitmap decoded bitmap
+         */
         @UiThread void onBitmapReady(Bitmap bitmap);
     }
 }

cameraview/src/main/utils/com/otaliastudios/cameraview/CropHelper.java

@@ -21,7 +21,7 @@ class CropHelper {
     // In doing so, EXIF data is deleted.
     static byte[] cropToJpeg(byte[] jpeg, AspectRatio targetRatio, int jpegCompression) {
 
-        Bitmap image = CameraUtils.decodeBitmap(jpeg);
+        Bitmap image = CameraUtils.decodeBitmap(jpeg, Integer.MAX_VALUE, Integer.MAX_VALUE);
         Rect cropRect = computeCrop(image.getWidth(), image.getHeight(), targetRatio);
         Bitmap crop = Bitmap.createBitmap(image, cropRect.left, cropRect.top, cropRect.width(), cropRect.height());
         image.recycle();

demo/src/main/java/com/otaliastudios/cameraview/demo/PicturePreviewActivity.java

@@ -27,8 +27,8 @@ public class PicturePreviewActivity extends Activity {
         setContentView(R.layout.activity_picture_preview);
         final ImageView imageView = findViewById(R.id.image);
         final MessageView nativeCaptureResolution = findViewById(R.id.nativeCaptureResolution);
-        final MessageView actualResolution = findViewById(R.id.actualResolution);
-        final MessageView approxUncompressedSize = findViewById(R.id.approxUncompressedSize);
+        // final MessageView actualResolution = findViewById(R.id.actualResolution);
+        // final MessageView approxUncompressedSize = findViewById(R.id.approxUncompressedSize);
         final MessageView captureLatency = findViewById(R.id.captureLatency);
 
         final long delay = getIntent().getLongExtra("delay", 0);
@@ -40,25 +40,25 @@ public class PicturePreviewActivity extends Activity {
             return;
         }
 
-        CameraUtils.decodeBitmap(b, new CameraUtils.BitmapCallback() {
+        CameraUtils.decodeBitmap(b, 1000, 1000, new CameraUtils.BitmapCallback() {
             @Override
             public void onBitmapReady(Bitmap bitmap) {
                 imageView.setImageBitmap(bitmap);
 
-                approxUncompressedSize.setTitle("Approx. uncompressed size");
-                approxUncompressedSize.setMessage(getApproximateFileMegabytes(bitmap) + "MB");
+                // approxUncompressedSize.setTitle("Approx. uncompressed size");
+                // approxUncompressedSize.setMessage(getApproximateFileMegabytes(bitmap) + "MB");
 
-                captureLatency.setTitle("Capture latency");
+                captureLatency.setTitle("Approx. capture latency");
                 captureLatency.setMessage(delay + " milliseconds");
 
                 // ncr and ar might be different when cropOutput is true.
                 AspectRatio nativeRatio = AspectRatio.of(nativeWidth, nativeHeight);
-                AspectRatio finalRatio = AspectRatio.of(bitmap.getWidth(), bitmap.getHeight());
                 nativeCaptureResolution.setTitle("Native capture resolution");
                 nativeCaptureResolution.setMessage(nativeWidth + "x" + nativeHeight + " (" + nativeRatio + ")");
 
-                actualResolution.setTitle("Actual resolution");
-                actualResolution.setMessage(bitmap.getWidth() + "x" + bitmap.getHeight() + " (" + finalRatio + ")");
+                // AspectRatio finalRatio = AspectRatio.of(bitmap.getWidth(), bitmap.getHeight());
+                // actualResolution.setTitle("Actual resolution");
+                // actualResolution.setMessage(bitmap.getWidth() + "x" + bitmap.getHeight() + " (" + finalRatio + ")");
             }
         });
 

demo/src/main/res/layout/activity_picture_preview.xml

@@ -20,15 +20,15 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"/>
 
-        <com.otaliastudios.cameraview.demo.MessageView
+        <!-- com.otaliastudios.cameraview.demo.MessageView
             android:id="@+id/actualResolution"
             android:layout_width="match_parent"
-            android:layout_height="wrap_content"/>
+            android:layout_height="wrap_content"/-->
 
-        <com.otaliastudios.cameraview.demo.MessageView
+        <!-- com.otaliastudios.cameraview.demo.MessageView
             android:id="@+id/approxUncompressedSize"
             android:layout_width="match_parent"
-            android:layout_height="wrap_content"/>
+            android:layout_height="wrap_content"/-->
 
         <com.otaliastudios.cameraview.demo.MessageView
             android:id="@+id/captureLatency"