Scale cursor speed to native resolution

Try to scale pointer coordinate deltas from a display with one resolution in the browser to a display (frame size) of the emulator.

web/js/stream/stream.js

@@ -179,7 +179,9 @@ const stream = (() => {
 
             if (fullscreen && !pointerLocked) {
                 // event.pub(POINTER_LOCK_CHANGE, screen);
-                await screen.requestPointerLock();
+                await screen.requestPointerLock(
+                    // { unadjustedMovement: true,}
+                );
             }
 
             screen.onpointerdown = fullscreen ? handlePointerDown : null;
@@ -188,8 +190,29 @@ const stream = (() => {
             // !to flipped
         })
 
+        const scaleCursorPos = (x, y) => {
+            const rez = {dx: 0, dy: 0}
+            const nzx = x !== 0;
+            const nzy = y !== 0;
+
+            const arW = screen.offsetHeight * state.aspect;
+
+            const sw = arW / screen.videoWidth;
+            const sh = screen.offsetHeight / screen.videoHeight;
+
+            rez.dx = Math.round(x / sw);
+            rez.dy = Math.round(y / sh);
+
+            // revert scaled to zero values
+            rez.dx = (nzx && rez.dx === 0) ? x : rez.dx;
+            rez.dy = (nzy && rez.dy === 0) ? y : rez.dy;
+
+            return rez;
+        }
+
         const handlePointerMove = (e) => {
-            event.pub(MOUSE_MOVED, {dx: e.movementX, dy: e.movementY});
+            const delta = scaleCursorPos(e.movementX, e.movementY);
+            event.pub(MOUSE_MOVED, delta);
         }
 
         event.sub(POINTER_LOCK_CHANGE, (lockedEl) => {