Fix grid sizing when viewport reports tiny dimensions

src/components/grid.tsx

@@ -43,6 +43,13 @@ export class Grid extends React.PureComponent<Props, {}> {
   // [width][idx] -> badness
   private rowsMemo: Map<number, Map<number, BadList>> = new Map();
 
+  componentDidUpdate(prevProps: Props) {
+    // The memoized rows depend on the image list; clear when the set changes
+    if (prevProps.images !== this.props.images) {
+      this.rowsMemo.clear();
+    }
+  }
+
   rows(idx: number): BadList {
     const targetHeight = this._rowHeight();
 

src/components/root.tsx

@@ -23,18 +23,27 @@ export class Root extends React.PureComponent<Props, State> {
   // innerWidth gets messed up when rotating phones from landscape -> portrait,
   // and chrome seems to not report innerWidth correctly when scrollbars are present
   private _viewWidth = (): number => {
-    return Math.min(
+    const widths = [
       window.innerWidth,
-      window.outerWidth || Infinity,
+      window.outerWidth,
-      document.body.clientWidth
+      document.documentElement?.clientWidth,
-    );
+      document.body?.clientWidth,
+    ].filter((w): w is number => typeof w === "number" && w > 0 && isFinite(w));
+
+    // Use the largest reasonable value to avoid shrinking the grid when a single
+    // measurement source temporarily reports something tiny.
+    return widths.length > 0 ? Math.max(...widths) : 0;
   };
 
   private _viewHeight = (): number => {
-    return Math.min(
+    const heights = [
-      window.outerHeight || Infinity,
+      window.innerHeight,
-      document.body.clientHeight || Infinity
+      window.outerHeight,
-    );
+      document.documentElement?.clientHeight,
+      document.body?.clientHeight,
+    ].filter((h): h is number => typeof h === "number" && h > 0 && isFinite(h));
+
+    return heights.length > 0 ? Math.max(...heights) : 0;
   };
 
   state: State = {