feat(ui): simpler dnd indicator for right panel tabs

We can use the drop overlay component directly for this, without needing to add it as a `noop` dnd target.

Other changes:
- The `label` prop is now used to conditionally render the label - every drop target provides its own label, so this doesn't break anything.
- Add `withBackdrop` prop to control whether we apply the dimmed drop target effect.

invokeai/frontend/web/src/common/components/IAIDropOverlay.tsx

@@ -1,15 +1,14 @@
 import { Flex, Text } from '@invoke-ai/ui-library';
 import { memo } from 'react';
-import { useTranslation } from 'react-i18next';
 
 type Props = {
   isOver: boolean;
   label?: string;
+  withBackdrop?: boolean;
 };
 
 const IAIDropOverlay = (props: Props) => {
-  const { t } = useTranslation();
-  const { isOver, label = t('gallery.drop') } = props;
+  const { isOver, label, withBackdrop = true } = props;
   return (
     <Flex position="absolute" top={0} right={0} bottom={0} left={0}>
       <Flex
@@ -20,7 +19,7 @@ const IAIDropOverlay = (props: Props) => {
         left={0}
         w="full"
         h="full"
-        bg="base.900"
+        bg={withBackdrop ? 'base.900' : 'transparent'}
         opacity={0.7}
         borderRadius="base"
         alignItems="center"
@@ -45,16 +44,18 @@ const IAIDropOverlay = (props: Props) => {
         alignItems="center"
         justifyContent="center"
       >
-        <Text
-          fontSize="lg"
-          fontWeight="semibold"
-          color={isOver ? 'invokeYellow.300' : 'base.500'}
-          transitionProperty="common"
-          transitionDuration="0.1s"
-          textAlign="center"
-        >
-          {label}
-        </Text>
+        {label && (
+          <Text
+            fontSize="lg"
+            fontWeight="semibold"
+            color={isOver ? 'invokeYellow.300' : 'base.500'}
+            transitionProperty="common"
+            transitionDuration="0.1s"
+            textAlign="center"
+          >
+            {label}
+          </Text>
+        )}
       </Flex>
     </Flex>
   );

invokeai/frontend/web/src/features/controlLayers/components/CanvasRightPanel.tsx

@@ -1,6 +1,7 @@
 import { useDndContext } from '@dnd-kit/core';
 import { Box, Button, Spacer, Tab, TabList, TabPanel, TabPanels, Tabs } from '@invoke-ai/ui-library';
 import { useAppDispatch, useAppSelector } from 'app/store/storeHooks';
+import IAIDropOverlay from 'common/components/IAIDropOverlay';
 import { CanvasLayersPanelContent } from 'features/controlLayers/components/CanvasLayersPanelContent';
 import { CanvasManagerProviderGate } from 'features/controlLayers/contexts/CanvasManagerProviderGate';
 import { selectEntityCountActive } from 'features/controlLayers/store/selectors';
@@ -9,7 +10,7 @@ import { useImageViewer } from 'features/gallery/components/ImageViewer/useImage
 import { useRegisteredHotkeys } from 'features/system/components/HotkeysModal/useHotkeyData';
 import { selectActiveTabCanvasRightPanel } from 'features/ui/store/uiSelectors';
 import { activeTabCanvasRightPanelChanged } from 'features/ui/store/uiSlice';
-import { memo, useCallback, useMemo, useRef } from 'react';
+import { memo, useCallback, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 
 export const CanvasRightPanel = memo(() => {
@@ -78,12 +79,15 @@ CanvasRightPanel.displayName = 'CanvasRightPanel';
 
 const PanelTabs = memo(() => {
   const { t } = useTranslation();
+  const activeTab = useAppSelector(selectActiveTabCanvasRightPanel);
   const activeEntityCount = useAppSelector(selectEntityCountActive);
   const tabTimeout = useRef<number | null>(null);
   const dndCtx = useDndContext();
   const dispatch = useAppDispatch();
+  const [mouseOverTab, setMouseOverTab] = useState<'layers' | 'gallery' | null>(null);
 
   const onOnMouseOverLayersTab = useCallback(() => {
+    setMouseOverTab('layers');
     tabTimeout.current = window.setTimeout(() => {
       if (dndCtx.active) {
         dispatch(activeTabCanvasRightPanelChanged('layers'));
@@ -92,6 +96,7 @@ const PanelTabs = memo(() => {
   }, [dndCtx.active, dispatch]);
 
   const onOnMouseOverGalleryTab = useCallback(() => {
+    setMouseOverTab('gallery');
     tabTimeout.current = window.setTimeout(() => {
       if (dndCtx.active) {
         dispatch(activeTabCanvasRightPanelChanged('gallery'));
@@ -100,6 +105,7 @@ const PanelTabs = memo(() => {
   }, [dndCtx.active, dispatch]);
 
   const onMouseOut = useCallback(() => {
+    setMouseOverTab(null);
     if (tabTimeout.current) {
       clearTimeout(tabTimeout.current);
     }
@@ -118,9 +124,17 @@ const PanelTabs = memo(() => {
         <Box as="span" w="full">
           {layersTabLabel}
         </Box>
+        {dndCtx.active && activeTab !== 'layers' && (
+          <IAIDropOverlay isOver={mouseOverTab === 'layers'} withBackdrop={false} />
+        )}
       </Tab>
-      <Tab position="relative" onMouseOver={onOnMouseOverGalleryTab} onMouseOut={onMouseOut}>
-        {t('gallery.gallery')}
+      <Tab position="relative" onMouseOver={onOnMouseOverGalleryTab} onMouseOut={onMouseOut} w={32}>
+        <Box as="span" w="full">
+          {t('gallery.gallery')}
+        </Box>
+        {dndCtx.active && activeTab !== 'gallery' && (
+          <IAIDropOverlay isOver={mouseOverTab === 'gallery'} withBackdrop={false} />
+        )}
       </Tab>
     </>
   );