Avoid fractional pixel sizes from Display

kasmweb/core/display.js

@@ -8,6 +8,7 @@
 
 import * as Log from './util/logging.js';
 import Base64 from "./base64.js";
+import { toSigned32bit } from './util/int.js';
 
 export default class Display {
     constructor(target) {
@@ -184,14 +185,14 @@ export default class Display {
         if (this._scale === 0) {
             return 0;
         }
-        return x / this._scale + this._viewportLoc.x;
+        return toSigned32bit(x / this._scale + this._viewportLoc.x);
     }
 
     absY(y) {
         if (this._scale === 0) {
             return 0;
         }
-        return y / this._scale + this._viewportLoc.y;
+        return toSigned32bit(y / this._scale + this._viewportLoc.y);
     }
 
     resize(width, height) {