Refactor virtual display properties initialization

Following the changes from the previous commit, the behavior is now
identical when mirroring the main display or using the SurfaceControl
API.

Factorize the code to perform the initialization in a single location.

Refs #5605 <#5605>
PR #5614 <#5614>

server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java

@@ -124,35 +124,17 @@ public void start(Surface surface) throws IOException {
             inputSize = videoSize;
         }
 
-        int virtualDisplayId;
-        PositionMapper positionMapper;
         try {
             virtualDisplay = ServiceManager.getDisplayManager()
                     .createVirtualDisplay("scrcpy", inputSize.getWidth(), inputSize.getHeight(), displayId, surface);
-
-
-            if (displayId == 0) {
-                // Main display: send all events to the original display, relative to the device size
-                Size deviceSize = displayInfo.getSize();
-                positionMapper = PositionMapper.create(videoSize, transform, deviceSize);
-                virtualDisplayId = 0;
-            } else {
-                // The positions are relative to the virtual display, not the original display (so use inputSize, not deviceSize!)
-                positionMapper = PositionMapper.create(videoSize, transform, inputSize);
-                virtualDisplayId = virtualDisplay.getDisplay().getDisplayId();
-            }
             Ln.d("Display: using DisplayManager API");
         } catch (Exception displayManagerException) {
             try {
                 display = createDisplay();
 
                 Size deviceSize = displayInfo.getSize();
                 int layerStack = displayInfo.getLayerStack();
-
                 setDisplaySurface(display, surface, deviceSize.toRect(), inputSize.toRect(), layerStack);
-                virtualDisplayId = displayId;
-
-                positionMapper = PositionMapper.create(videoSize, transform, deviceSize);
                 Ln.d("Display: using SurfaceControl API");
             } catch (Exception surfaceControlException) {
                 Ln.e("Could not create display using DisplayManager", displayManagerException);
@@ -162,6 +144,18 @@ public void start(Surface surface) throws IOException {
         }
 
         if (vdListener != null) {
+            int virtualDisplayId;
+            PositionMapper positionMapper;
+            if (virtualDisplay == null || displayId == 0) {
+                // Surface control or main display: send all events to the original display, relative to the device size
+                Size deviceSize = displayInfo.getSize();
+                positionMapper = PositionMapper.create(videoSize, transform, deviceSize);
+                virtualDisplayId = displayId;
+            } else {
+                // The positions are relative to the virtual display, not the original display (so use inputSize, not deviceSize!)
+                positionMapper = PositionMapper.create(videoSize, transform, inputSize);
+                virtualDisplayId = virtualDisplay.getDisplay().getDisplayId();
+            }
             vdListener.onNewVirtualDisplay(virtualDisplayId, positionMapper);
         }
     }