openImageViewer(): take an optional callback

TODO.md

@@ -2,7 +2,6 @@
 
 - Image viewer: 
     - fix gifs
-    - double click on EventImage to open fullscreen
     - open externally in context menu in timeline thumbnail
     - hflickable support kinetic scrolling disabler and speed/decel settings
     - buttons 

src/gui/Pages/Chat/Timeline/EventImage.qml

@@ -66,11 +66,11 @@ HMxcImage {
         acceptedButtons: Qt.LeftButton
         acceptedModifiers: Qt.NoModifier
         gesturePolicy: TapHandler.ReleaseWithinBounds
+
         onTapped:
             eventList.selectedCount ?
             eventDelegate.toggleChecked() :
             eventList.openImageViewer(singleMediaInfo)
-
     }
 
     TapHandler {

src/gui/Pages/Chat/Timeline/EventList.qml

@@ -355,7 +355,7 @@ Rectangle {
             ) || utils.urlFileName(event.media_url)
         }
 
-        function openImageViewer(event, forLink="") {
+        function openImageViewer(event, forLink="", callback=null) {
             // if forLink is empty, this must be a media event
 
             const title =
@@ -390,11 +390,13 @@ Rectangle {
                     )
                 },
                 obj => {
-                    obj.openExternallyRequested.connect(() =>
+                    obj.openExternallyRequested.connect(() => {
                         forLink ?
                         Qt.openUrlExternally(forLink) :
                         eventList.openMediaExternally(event)
-                    )
+                    })
+
+                    if (callback) callback(obj)
                 },
             )
         }