feat(ui): minimum gallery size

Add `useMinimumPanelSize()` hook to provide minimum resizable panel sizes (in pixels).

The library we are using for the gallery panel uses percentages only. To provide a minimum size in pixels, we need to do some math to calculate the percentage of window size that corresponds to the desired min width in pixels.

invokeai/frontend/web/src/features/ui/components/InvokeTabs.tsx

@@ -36,6 +36,7 @@ import { FaFont, FaImage } from 'react-icons/fa';
 import ResizeHandle from './tabs/ResizeHandle';
 import ImageTab from './tabs/ImageToImage/ImageToImageTab';
 import AuxiliaryProgressIndicator from 'app/components/AuxiliaryProgressIndicator';
+import { useMinimumPanelSize } from '../hooks/useMinimumPanelSize';
 
 export interface InvokeTabInfo {
   id: InvokeTabName;
@@ -78,6 +79,9 @@ const enabledTabsSelector = createSelector(
   }
 );
 
+const MIN_GALLERY_WIDTH = 300;
+const DEFAULT_GALLERY_PCT = 20;
+
 const InvokeTabs = () => {
   const activeTab = useAppSelector(activeTabIndexSelector);
   const activeTabName = useAppSelector(activeTabNameSelector);
@@ -150,6 +154,9 @@ const InvokeTabs = () => {
     [enabledTabs]
   );
 
+  const { ref: galleryPanelRef, minSizePct: galleryMinSizePct } =
+    useMinimumPanelSize(MIN_GALLERY_WIDTH, DEFAULT_GALLERY_PCT, 'app');
+
   return (
     <Tabs
       defaultIndex={activeTab}
@@ -175,6 +182,7 @@ const InvokeTabs = () => {
         <AuxiliaryProgressIndicator />
       </TabList>
       <PanelGroup
+        id="app"
         autoSaveId="app"
         direction="horizontal"
         style={{ height: '100%', width: '100%' }}
@@ -188,11 +196,12 @@ const InvokeTabs = () => {
           <>
             <ResizeHandle />
             <Panel
+              ref={galleryPanelRef}
               onResize={handleResizeGallery}
               id="gallery"
               order={3}
-              defaultSize={10}
-              minSize={10}
+              defaultSize={galleryMinSizePct}
+              minSize={galleryMinSizePct}
               maxSize={50}
             >
               <ImageGalleryContent />

invokeai/frontend/web/src/features/ui/hooks/useMinimumPanelSize.ts

@@ -0,0 +1,70 @@
+// adapted from https://github.com/bvaughn/react-resizable-panels/issues/141#issuecomment-1540048714
+
+import {
+  RefObject,
+  useCallback,
+  useLayoutEffect,
+  useRef,
+  useState,
+} from 'react';
+import { ImperativePanelHandle } from 'react-resizable-panels';
+
+export const useMinimumPanelSize = (
+  minSizePx: number,
+  defaultSizePct: number,
+  groupId: string,
+  orientation: 'horizontal' | 'vertical' = 'horizontal'
+): { ref: RefObject<ImperativePanelHandle>; minSizePct: number } => {
+  const ref = useRef<ImperativePanelHandle>(null);
+  const [minSizePct, setMinSizePct] = useState(defaultSizePct);
+
+  const handleWindowResize = useCallback(() => {
+    const size = ref.current?.getSize();
+
+    if (size !== undefined && size < minSizePct) {
+      ref.current?.resize(minSizePct);
+    }
+  }, [minSizePct]);
+
+  useLayoutEffect(() => {
+    const panelGroup = document.querySelector(
+      `[data-panel-group-id="${groupId}"]`
+    );
+    const resizeHandles = document.querySelectorAll(
+      '[data-panel-resize-handle-id]'
+    );
+
+    if (!panelGroup) {
+      return;
+    }
+    const observer = new ResizeObserver(() => {
+      let dim =
+        orientation === 'horizontal'
+          ? panelGroup.getBoundingClientRect().width
+          : panelGroup.getBoundingClientRect().height;
+
+      resizeHandles.forEach((resizeHandle) => {
+        dim -=
+          orientation === 'horizontal'
+            ? resizeHandle.getBoundingClientRect().width
+            : resizeHandle.getBoundingClientRect().height;
+      });
+
+      // Minimum size in pixels is a percentage of the PanelGroup's width/height
+      setMinSizePct((minSizePx / dim) * 100);
+    });
+    observer.observe(panelGroup);
+    resizeHandles.forEach((resizeHandle) => {
+      observer.observe(resizeHandle);
+    });
+
+    window.addEventListener('resize', handleWindowResize);
+
+    return () => {
+      observer.disconnect();
+      window.removeEventListener('resize', handleWindowResize);
+    };
+  }, [groupId, handleWindowResize, minSizePct, minSizePx, orientation]);
+
+  return { ref, minSizePct };
+};