show a panorama button over images if appropriate

app/build.gradle

@@ -55,6 +55,7 @@ dependencies {
     implementation 'com.github.chrisbanes:PhotoView:2.1.3'
     implementation 'com.android.support.constraint:constraint-layout:1.1.2'
     implementation 'com.google.android.exoplayer:exoplayer-core:2.8.2'
+    implementation 'org.apache.sanselan:sanselan:0.97-incubator'
 
     kapt "android.arch.persistence.room:compiler:1.1.1"
     implementation "android.arch.persistence.room:runtime:1.1.1"

app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt

@@ -36,6 +36,8 @@ import com.simplemobiletools.gallery.helpers.ROTATE_BY_ASPECT_RATIO
 import com.simplemobiletools.gallery.models.Medium
 import it.sephiroth.android.library.exif2.ExifInterface
 import kotlinx.android.synthetic.main.pager_photo_item.view.*
+import org.apache.sanselan.common.byteSources.ByteSourceInputStream
+import org.apache.sanselan.formats.jpeg.JpegImageParser
 import pl.droidsonroids.gif.GifDrawable
 import java.io.File
 import java.io.FileOutputStream
@@ -46,6 +48,7 @@ class PhotoFragment : ViewPagerFragment() {
     private var isFullscreen = false
     private var wasInit = false
     private var useHalfResolution = false
+    private var isPanorama = false
     private var imageOrientation = -1
     private var gifDrawable: GifDrawable? = null
 
@@ -118,6 +121,7 @@ class PhotoFragment : ViewPagerFragment() {
         loadImage()
         initExtendedDetails()
         wasInit = true
+        checkIfPanorama()
 
         return view
     }
@@ -329,6 +333,18 @@ class PhotoFragment : ViewPagerFragment() {
         }
     }
 
+    private fun checkIfPanorama() {
+        isPanorama = try {
+            val inputStream = if (medium.path.startsWith("content:/")) context!!.contentResolver.openInputStream(Uri.parse(medium.path)) else File(medium.path).inputStream()
+            val imageParser = JpegImageParser().getXmpXml(ByteSourceInputStream(inputStream, medium.name), HashMap<String, Any>())
+            imageParser.contains("GPano:UsePanoramaViewer=\"True\"", true)
+        } catch (e: Exception) {
+            false
+        }
+
+        view.panorama_outline.beVisibleIf(isPanorama)
+    }
+
     private fun getImageOrientation(): Int {
         val defaultOrientation = -1
         var orient = defaultOrientation

app/src/main/res/layout/pager_photo_item.xml

@@ -18,6 +18,16 @@
         android:layout_height="match_parent"
         android:visibility="gone"/>
 
+    <ImageView
+        android:id="@+id/panorama_outline"
+        android:layout_width="@dimen/play_outline_size_big"
+        android:layout_height="@dimen/play_outline_size_big"
+        android:layout_centerInParent="true"
+        android:background="@android:color/transparent"
+        android:padding="@dimen/big_margin"
+        android:src="@drawable/ic_panorama"
+        android:visibility="gone"/>
+
     <TextView
         android:id="@+id/photo_details"
         android:layout_width="wrap_content"