panorama: loosened identification criteria, handle missing parameter

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/MetadataHandler.kt

@@ -594,14 +594,16 @@ class MetadataHandler(private val context: Context) : MethodCallHandler {
                     val metadata = ImageMetadataReader.readMetadata(input)
                     val xmpDirs = metadata.getDirectoriesOfType(XmpDirectory::class.java)
                     try {
-                        fun getProp(propName: String): Int? = xmpDirs.map { it.xmpMeta.getPropertyInteger(XMP.GPANO_SCHEMA_NS, propName) }.firstOrNull { it != null }
+                        fun getIntProp(propName: String): Int? = xmpDirs.map { it.xmpMeta.getPropertyInteger(XMP.GPANO_SCHEMA_NS, propName) }.firstOrNull { it != null }
+                        fun getStringProp(propName: String): String? = xmpDirs.map { it.xmpMeta.getPropertyString(XMP.GPANO_SCHEMA_NS, propName) }.firstOrNull { it != null }
                         val fields: FieldMap = hashMapOf(
-                            "croppedAreaLeft" to getProp(XMP.GPANO_CROPPED_AREA_LEFT_PROP_NAME),
+                            "croppedAreaLeft" to getIntProp(XMP.GPANO_CROPPED_AREA_LEFT_PROP_NAME),
-                            "croppedAreaTop" to getProp(XMP.GPANO_CROPPED_AREA_TOP_PROP_NAME),
+                            "croppedAreaTop" to getIntProp(XMP.GPANO_CROPPED_AREA_TOP_PROP_NAME),
-                            "croppedAreaWidth" to getProp(XMP.GPANO_CROPPED_AREA_WIDTH_PROP_NAME),
+                            "croppedAreaWidth" to getIntProp(XMP.GPANO_CROPPED_AREA_WIDTH_PROP_NAME),
-                            "croppedAreaHeight" to getProp(XMP.GPANO_CROPPED_AREA_HEIGHT_PROP_NAME),
+                            "croppedAreaHeight" to getIntProp(XMP.GPANO_CROPPED_AREA_HEIGHT_PROP_NAME),
-                            "fullPanoWidth" to getProp(XMP.GPANO_FULL_PANO_WIDTH_PROP_NAME),
+                            "fullPanoWidth" to getIntProp(XMP.GPANO_FULL_PANO_WIDTH_PROP_NAME),
-                            "fullPanoHeight" to getProp(XMP.GPANO_FULL_PANO_HEIGHT_PROP_NAME),
+                            "fullPanoHeight" to getIntProp(XMP.GPANO_FULL_PANO_HEIGHT_PROP_NAME),
+                            "projectionType" to (getStringProp(XMP.GPANO_PROJECTION_TYPE_PROP_NAME) ?: XMP.GPANO_PROJECTION_TYPE_DEFAULT),
                         )
                         result.success(fields)
                         return

android/app/src/main/kotlin/deckers/thibault/aves/metadata/XMP.kt

@@ -54,18 +54,19 @@ object XMP {
     const val GPANO_CROPPED_AREA_TOP_PROP_NAME = "GPano:CroppedAreaTopPixels"
     const val GPANO_FULL_PANO_HEIGHT_PROP_NAME = "GPano:FullPanoHeightPixels"
     const val GPANO_FULL_PANO_WIDTH_PROP_NAME = "GPano:FullPanoWidthPixels"
-    private const val GPANO_PROJECTION_TYPE_PROP_NAME = "GPano:ProjectionType"
+    const val GPANO_PROJECTION_TYPE_PROP_NAME = "GPano:ProjectionType"
+    const val GPANO_PROJECTION_TYPE_DEFAULT = "equirectangular"
 
     private const val PMTM_IS_PANO360 = "pmtm:IsPano360"
 
+    // `GPano:ProjectionType` is required by spec but it is sometimes missing, assuming default
+    // `GPano:FullPanoHeightPixels` is required by spec but it is sometimes missing (e.g. Samsung Camera app panorama mode)
     private val gpanoRequiredProps = listOf(
         GPANO_CROPPED_AREA_HEIGHT_PROP_NAME,
         GPANO_CROPPED_AREA_WIDTH_PROP_NAME,
         GPANO_CROPPED_AREA_LEFT_PROP_NAME,
         GPANO_CROPPED_AREA_TOP_PROP_NAME,
-        GPANO_FULL_PANO_HEIGHT_PROP_NAME,
         GPANO_FULL_PANO_WIDTH_PROP_NAME,
-        GPANO_PROJECTION_TYPE_PROP_NAME,
     )
 
     // extensions

lib/model/panorama.dart

@@ -4,24 +4,38 @@ import 'package:flutter/widgets.dart';
 class PanoramaInfo {
   final Rect croppedAreaRect;
   final Size fullPanoSize;
+  final String projectionType;
 
   PanoramaInfo({
     this.croppedAreaRect,
     this.fullPanoSize,
+    this.projectionType,
   });
 
   factory PanoramaInfo.fromMap(Map map) {
-    final cLeft = map['croppedAreaLeft'] as int;
+    var cLeft = map['croppedAreaLeft'] as int;
-    final cTop = map['croppedAreaTop'] as int;
+    var cTop = map['croppedAreaTop'] as int;
     final cWidth = map['croppedAreaWidth'] as int;
     final cHeight = map['croppedAreaHeight'] as int;
+    var fWidth = map['fullPanoWidth'] as int;
+    var fHeight = map['fullPanoHeight'] as int;
+    final projectionType = map['projectionType'] as String;
+
+    // handle missing `fullPanoHeight` (e.g. Samsung camera app panorama mode)
+    if (fHeight == null && cWidth != null && cHeight != null) {
+      // assume the cropped area is actually covering 360 degrees horizontally
+      // even when `croppedAreaLeft` is non zero
+      fWidth = cWidth;
+      fHeight = (fWidth / 2).round();
+      cTop = ((fHeight - cHeight) / 2).round();
+      cLeft = 0;
+    }
+
     Rect croppedAreaRect;
     if (cLeft != null && cTop != null && cWidth != null && cHeight != null) {
       croppedAreaRect = Rect.fromLTWH(cLeft.toDouble(), cTop.toDouble(), cWidth.toDouble(), cHeight.toDouble());
     }
 
-    final fWidth = map['fullPanoWidth'] as int;
-    final fHeight = map['fullPanoHeight'] as int;
     Size fullPanoSize;
     if (fWidth != null && fHeight != null) {
       fullPanoSize = Size(fWidth.toDouble(), fHeight.toDouble());
@@ -30,11 +44,12 @@ class PanoramaInfo {
     return PanoramaInfo(
       croppedAreaRect: croppedAreaRect,
       fullPanoSize: fullPanoSize,
+      projectionType: projectionType,
     );
   }
 
   bool get hasCroppedArea => croppedAreaRect != null && fullPanoSize != null;
 
   @override
-  String toString() => '$runtimeType#${shortHash(this)}{croppedAreaRect=$croppedAreaRect, fullPanoSize=$fullPanoSize}';
+  String toString() => '$runtimeType#${shortHash(this)}{croppedAreaRect=$croppedAreaRect, fullPanoSize=$fullPanoSize, projectionType=$projectionType}';
 }