[feat] allow pinch zoom outside the remote image on mobile

apps/ios/CrossDeskMobile/Input/RemoteTouchInputView.swift

@@ -375,7 +375,8 @@ final class RemoteTouchSurface: UIView, UIGestureRecognizerDelegate {
         let focus = recognizer.location(in: self)
         switch recognizer.state {
         case .began:
-            pinchActive = renderRect()?.contains(focus) == true
+            // The full touch surface accepts pinches, including letterboxing.
+            pinchActive = bounds.contains(focus) && renderRect() != nil
             recognizer.scale = 1
         case .changed:
             guard pinchActive else { return }
@@ -414,13 +415,13 @@ final class RemoteTouchSurface: UIView, UIGestureRecognizerDelegate {
         if viewportScale > 1.001 || pinchActive {
             switch recognizer.state {
             case .began:
-                viewportPanActive = renderRect()?.contains(
+                viewportPanActive = pinchActive || renderRect()?.contains(
                     recognizer.location(in: self)
                 ) == true
                 recognizer.setTranslation(.zero, in: self)
             case .changed:
                 if !viewportPanActive {
-                    viewportPanActive = renderRect()?.contains(
+                    viewportPanActive = pinchActive || renderRect()?.contains(
                         recognizer.location(in: self)
                     ) == true
                 }

apps/ios/README.md

@@ -431,6 +431,11 @@ Old previews saved without this choice are removed on upgrade.
 
 ## Pointer edge panning
 
+Pinch-to-zoom can start anywhere on the touch surface, including black margins
+outside the image, in either pointer mode. A pinch also follows the fingers'
+midpoint movement when it starts in a margin. Held virtual mouse buttons still
+prevent viewport gestures.
+
 In relative mouse mode, continuing to move outward at the top or bottom of the
 visible image pans the video vertically in the opposite direction. Moving
 down-left at the bottom edge pans upward without shifting the video horizontally;