fix: allow JSON state updates to reset flex group sizes (#824)

Fixes #823

Author: seankmartin

src/ui/side_panel.ts

@@ -263,6 +263,7 @@ export class SidePanelManager extends RefCounted {
   private registeredPanels = new Set<RegisteredSidePanel>();
   dragSource: DragSource | undefined;
   private layoutNeedsUpdate = false;
+  private shouldResetFlexGroupSizes = false;
 
   get visible() {
     return this.visibility.visible;
@@ -333,6 +334,17 @@ export class SidePanelManager extends RefCounted {
     this.dragSource = undefined;
   }
 
+  /**
+   * Once a panel is added to a flex group, the panel no longer controls the
+   * size of the flex group. This resets the flex group sizes so that
+   * panels can set the size of the flex group. This is useful when
+   * panel sizes are manually set from the JSON state.
+   */
+  reset() {
+    this.shouldResetFlexGroupSizes = true;
+    this.invalidateLayout();
+  }
+
   private makeDropZone(
     side: Side,
     crossIndex: number,
@@ -460,6 +472,7 @@ export class SidePanelManager extends RefCounted {
       yield self.sides.bottom.outerDropZoneElement;
     }
     updateChildren(this.centerColumn, getColumnChildren());
+    this.shouldResetFlexGroupSizes = false;
   }
 
   private makeCrossGutter(side: Side, crossIndex: number) {
@@ -689,12 +702,11 @@ export class SidePanelManager extends RefCounted {
             }
             const oldLocation = cell.registeredPanel.location.value;
             if (oldLocation.visible) {
-              flexGroup.crossSize = Math.max(
-                minSize,
-                flexGroup.crossSize === -1
+              const suggestedSize =
+                self.shouldResetFlexGroupSizes || flexGroup.crossSize === -1
                   ? oldLocation.size
-                  : flexGroup.crossSize,
-              );
+                  : flexGroup.crossSize;
+              flexGroup.crossSize = Math.max(minSize, suggestedSize);
             }
             if (
               oldLocation[crossKey] !== crossIndex ||

src/viewer.ts

@@ -355,6 +355,11 @@ class TrackableViewerState extends CompoundTrackable {
       viewer.perspectiveViewBackgroundColor,
     );
   }
+
+  reset() {
+    super.reset();
+    this.viewer.sidePanelManager.reset();
+  }
 }
 
 export class Viewer extends RefCounted implements ViewerState {