Fix image picker

app/src/main/java/eu/steffo/twom/create/CreateActivityContent.kt

@@ -1,6 +1,9 @@
 package eu.steffo.twom.create
 
+import android.graphics.Bitmap
 import android.graphics.BitmapFactory
+import android.graphics.Matrix
+import android.media.ExifInterface
 import android.net.Uri
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.PickVisualMediaRequest
@@ -54,10 +57,75 @@ fun CreateActivityContent(
             if (it == null) {
                 avatarBitmap = null
             } else {
-                val stream = context.contentResolver.openInputStream(it)
+                // Open two streams...
-                if (stream != null) {
+                // One to read the EXIF metadata from:
-                    avatarBitmap = BitmapFactory.decodeStream(stream).asImageBitmap()
+                val exifStream = context.contentResolver.openInputStream(it)
-                    stream.close()
+                // One to read the image data itself from:
+                val bitmapStream = context.contentResolver.openInputStream(it)
+
+                if (exifStream != null && bitmapStream != null) {
+                    // Use the EXIF metadata to determine the orientation of the image
+                    val exifInterface = ExifInterface(exifStream)
+                    val orientation =
+                        exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1)
+                    exifStream.close()
+
+                    // Parse the image data as-is
+                    val originalBitmap = BitmapFactory.decodeStream(bitmapStream)
+                    bitmapStream.close()
+
+                    // Determine the starting points and the size to crop the image to a 1:1 square
+                    val xStart: Int
+                    val yStart: Int
+                    val size: Int
+                    if (originalBitmap.width > originalBitmap.height) {
+                        yStart = 0
+                        xStart = (originalBitmap.width - originalBitmap.height) / 2
+                        size = originalBitmap.height
+                    } else {
+                        xStart = 0
+                        yStart = (originalBitmap.height - originalBitmap.width) / 2
+                        size = originalBitmap.width
+                    }
+
+                    // Create a transformation matrix to rotate the bitmap based on the orientation
+                    val transformationMatrix: Matrix = Matrix()
+
+                    // TODO: Make sure these transformations are valid
+                    when (orientation) {
+                        ExifInterface.ORIENTATION_FLIP_HORIZONTAL -> transformationMatrix.postScale(
+                            -1f,
+                            1f
+                        )
+
+                        ExifInterface.ORIENTATION_ROTATE_180 -> transformationMatrix.postRotate(180f)
+                        ExifInterface.ORIENTATION_FLIP_VERTICAL -> transformationMatrix.postScale(
+                            1f,
+                            -1f
+                        )
+
+                        ExifInterface.ORIENTATION_TRANSPOSE -> {/* TODO: Transpose the image Matrix */
+                        }
+
+                        ExifInterface.ORIENTATION_ROTATE_90 -> transformationMatrix.postRotate(90f)
+                        ExifInterface.ORIENTATION_TRANSVERSE -> {/* TODO: Flip horizontally the image Matrix, then transpose it */
+                        }
+
+                        ExifInterface.ORIENTATION_ROTATE_270 -> transformationMatrix.postRotate(270f)
+                    }
+
+                    // Crop the bitmap
+                    val croppedBitmap = Bitmap.createBitmap(
+                        originalBitmap,
+                        xStart,
+                        yStart,
+                        size,
+                        size,
+                        transformationMatrix,
+                        true
+                    )
+
+                    avatarBitmap = croppedBitmap.asImageBitmap()
                 }
             }
         }