Fix Image Scaling/Rotating

app/src/main/java/com/owncloud/android/ui/preview/PreviewImageFragment.kt

@@ -64,7 +64,6 @@ import com.owncloud.android.ui.fragment.FileFragment
 import com.owncloud.android.ui.preview.PreviewMediaFragment.Companion.newInstance
 import com.owncloud.android.utils.BitmapUtils
 import com.owncloud.android.utils.DisplayUtils
-import com.owncloud.android.utils.MimeType
 import com.owncloud.android.utils.MimeTypeUtil
 import com.owncloud.android.utils.theme.ViewThemeUtils
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings
@@ -529,11 +528,7 @@ class PreviewImageFragment : FileFragment(), Injectable {
                         }
 
                         try {
-                            bitmapResult = BitmapUtils.decodeSampledBitmapFromFile(
-                                storagePath,
-                                minWidth,
-                                minHeight
-                            )
+                            bitmapResult = BitmapUtils.retrieveBitmapFromFile(storagePath, minWidth, minHeight)
 
                             if (isCancelled) {
                                 return LoadImage(bitmapResult, null, ocFile)
@@ -543,11 +538,6 @@ class PreviewImageFragment : FileFragment(), Injectable {
                                 mErrorMessageId = R.string.preview_image_error_unknown_format
                                 Log_OC.e(TAG, "File could not be loaded as a bitmap: $storagePath")
                                 break
-                            } else {
-                                if (MimeType.JPEG.equals(ocFile.mimeType, ignoreCase = true)) {
-                                    // Rotate image, obeying exif tag.
-                                    bitmapResult = BitmapUtils.rotateImage(bitmapResult, storagePath)
-                                }
                             }
                         } catch (e: OutOfMemoryError) {
                             mErrorMessageId = R.string.common_error_out_memory

app/src/main/java/com/owncloud/android/utils/BitmapUtils.java

@@ -114,7 +114,44 @@ public static Bitmap decodeSampledBitmapFromFile(String srcPath, int reqWidth, i
         return BitmapFactory.decodeFile(srcPath, options);
     }
 
+    /**
+     * Decodes a bitmap from a file containing it minimizing the memory use. Scales image to screen size.
+     *
+     * @param storagePath   Absolute path to the file containing the image.
+     */
+    public static Bitmap retrieveBitmapFromFile(String storagePath, int minWidth, int minHeight){
+        // Get the original dimensions of the bitmap
+        var bitmapResolution = getImageResolution(storagePath);
+        var originalWidth = bitmapResolution[0];
+        var originalHeight = bitmapResolution[1];
+
+        // Detect Orientation and swap height/width if the image is to be rotated
+        var shouldRotate = detectRotateImage(storagePath);
+        if (shouldRotate) {
+            // Swap the width and height
+            var tempWidth = originalWidth;
+            originalWidth = originalHeight;
+            originalHeight = tempWidth;
+        }
+
+        var bitmapResult = decodeSampledBitmapFromFile(
+            storagePath, originalWidth, originalHeight);
+
+        // Calculate the scaling factors based on screen dimensions
+        var widthScaleFactor = (float) minWidth/ bitmapResult.getWidth();
+        var heightScaleFactor = (float) minHeight / bitmapResult.getHeight();
+
+        // Use the smaller scaling factor to maintain aspect ratio
+        var scaleFactor = Math.min(widthScaleFactor, heightScaleFactor);
 
+        // Calculate the new scaled width and height
+        var scaledWidth = (int) (bitmapResult.getWidth() * scaleFactor);
+        var scaledHeight = (int) (bitmapResult.getHeight() * scaleFactor);
+
+        bitmapResult = scaleBitmap(bitmapResult,scaledWidth,scaledHeight);
+
+        return bitmapResult;
+    }
     /**
      * Calculates a proper value for options.inSampleSize in order to decode a Bitmap minimizing the memory overload and
      * covering a target surface of reqWidth x reqHeight if the original image is big enough.
@@ -162,6 +199,18 @@ public static Bitmap scaleBitmap(Bitmap bitmap, float px, int width, int height,
         return Bitmap.createScaledBitmap(bitmap, w, h, true);
     }
 
+    /**
+     * scales a given bitmap depending on the given size parameters.
+     *
+     * @param bitmap the bitmap to be scaled
+     * @param width  the width
+     * @param height the height
+     * @return the scaled bitmap
+     */
+    public static Bitmap scaleBitmap(Bitmap bitmap, int width, int height) {
+        return Bitmap.createScaledBitmap(bitmap, width, height, true);
+    }
+
     /**
      * Rotate bitmap according to EXIF orientation. Cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
      *
@@ -230,6 +279,44 @@ public static Bitmap rotateImage(Bitmap bitmap, String storagePath) {
         return resultBitmap;
     }
 
+    /**
+     * Detect if Image will be rotated according to EXIF orientation. Cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
+     *
+     * @param storagePath Path to source file of bitmap. Needed for EXIF information.
+     * @return true if image's orientation determines it will be rotated to where height and width change
+     */
+    public static boolean detectRotateImage(String storagePath) {
+        try {
+            ExifInterface exifInterface = new ExifInterface(storagePath);
+            int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
+
+            if (orientation != ExifInterface.ORIENTATION_NORMAL) {
+                switch (orientation) {
+                    // 5
+                    case ExifInterface.ORIENTATION_TRANSPOSE: {
+                        return true;
+                    }
+                    // 6
+                    case ExifInterface.ORIENTATION_ROTATE_90: {
+                        return true;
+                    }
+                    // 7
+                    case ExifInterface.ORIENTATION_TRANSVERSE: {
+                        return true;
+                    }
+                    // 8
+                    case ExifInterface.ORIENTATION_ROTATE_270: {
+                        return true;
+                    }
+                }
+            }
+        }
+        catch (Exception exception) {
+            Log_OC.e("BitmapUtil", "Could not read orientation at: " + storagePath);
+        }
+        return false;
+    }
+
     public static int[] getImageResolution(String srcPath) {
         Options options = new Options();
         options.inJustDecodeBounds = true;