From 00cd9fadeca207dfa20963e4a4734012982de9ab Mon Sep 17 00:00:00 2001
From: Christian Byrne <cbyrne@comfy.org>
Date: Mon, 28 Jul 2025 23:51:09 -0700
Subject: [PATCH] [feat] Prevent browser zoom on UI components with canvas
 wheel event forwarding (#4574)

---
 src/components/graph/GraphCanvasMenu.vue      |   3 +
 src/components/graph/SelectionToolbox.vue     |   3 +
 .../graph/useCanvasInteractions.ts            |  59 ++++++++
 .../graph/useCanvasInteractions.test.ts       | 126 ++++++++++++++++++
 4 files changed, 191 insertions(+)
 create mode 100644 src/composables/graph/useCanvasInteractions.ts
 create mode 100644 tests-ui/tests/composables/graph/useCanvasInteractions.test.ts

diff --git a/src/components/graph/GraphCanvasMenu.vue b/src/components/graph/GraphCanvasMenu.vue
index f0b208ce4..70c44c2c5 100644
--- a/src/components/graph/GraphCanvasMenu.vue
+++ b/src/components/graph/GraphCanvasMenu.vue
@@ -1,6 +1,7 @@
 <template>
   <ButtonGroup
     class="p-buttongroup-vertical absolute bottom-[10px] right-[10px] z-[1000]"
+    @wheel="canvasInteractions.handleWheel"
   >
     <Button
       v-tooltip.left="t('graphCanvasMenu.zoomIn')"
@@ -75,6 +76,7 @@ import ButtonGroup from 'primevue/buttongroup'
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import { useCanvasInteractions } from '@/composables/graph/useCanvasInteractions'
 import { useCommandStore } from '@/stores/commandStore'
 import { useCanvasStore } from '@/stores/graphStore'
 import { useSettingStore } from '@/stores/settingStore'
@@ -83,6 +85,7 @@ const { t } = useI18n()
 const commandStore = useCommandStore()
 const canvasStore = useCanvasStore()
 const settingStore = useSettingStore()
+const canvasInteractions = useCanvasInteractions()
 
 const minimapVisible = computed(() => settingStore.get('Comfy.Minimap.Visible'))
 const linkHidden = computed(
diff --git a/src/components/graph/SelectionToolbox.vue b/src/components/graph/SelectionToolbox.vue
index 3b316b06b..2412b703f 100644
--- a/src/components/graph/SelectionToolbox.vue
+++ b/src/components/graph/SelectionToolbox.vue
@@ -5,6 +5,7 @@
       header: 'hidden',
       content: 'p-0 flex flex-row'
     }"
+    @wheel="canvasInteractions.handleWheel"
   >
     <ExecuteButton />
     <ColorPickerButton />
@@ -39,6 +40,7 @@ import HelpButton from '@/components/graph/selectionToolbox/HelpButton.vue'
 import MaskEditorButton from '@/components/graph/selectionToolbox/MaskEditorButton.vue'
 import PinButton from '@/components/graph/selectionToolbox/PinButton.vue'
 import RefreshButton from '@/components/graph/selectionToolbox/RefreshButton.vue'
+import { useCanvasInteractions } from '@/composables/graph/useCanvasInteractions'
 import { useExtensionService } from '@/services/extensionService'
 import { type ComfyCommandImpl, useCommandStore } from '@/stores/commandStore'
 import { useCanvasStore } from '@/stores/graphStore'
@@ -46,6 +48,7 @@ import { useCanvasStore } from '@/stores/graphStore'
 const commandStore = useCommandStore()
 const canvasStore = useCanvasStore()
 const extensionService = useExtensionService()
+const canvasInteractions = useCanvasInteractions()
 
 const extensionToolboxCommands = computed<ComfyCommandImpl[]>(() => {
   const commandIds = new Set<string>(
diff --git a/src/composables/graph/useCanvasInteractions.ts b/src/composables/graph/useCanvasInteractions.ts
new file mode 100644
index 000000000..dca1bd125
--- /dev/null
+++ b/src/composables/graph/useCanvasInteractions.ts
@@ -0,0 +1,59 @@
+import { computed } from 'vue'
+
+import { app } from '@/scripts/app'
+import { useSettingStore } from '@/stores/settingStore'
+
+/**
+ * Composable for handling canvas interactions from Vue components.
+ * This provides a unified way to forward events to the LiteGraph canvas
+ * and will be the foundation for migrating canvas interactions to Vue.
+ */
+export function useCanvasInteractions() {
+  const settingStore = useSettingStore()
+
+  const isStandardNavMode = computed(
+    () => settingStore.get('Comfy.Canvas.NavigationMode') === 'standard'
+  )
+
+  /**
+   * Handles wheel events from UI components that should be forwarded to canvas
+   * when appropriate (e.g., Ctrl+wheel for zoom in standard mode)
+   */
+  const handleWheel = (event: WheelEvent) => {
+    // In standard mode, Ctrl+wheel should go to canvas for zoom
+    if (isStandardNavMode.value && (event.ctrlKey || event.metaKey)) {
+      event.preventDefault() // Prevent browser zoom
+      forwardEventToCanvas(event)
+      return
+    }
+
+    // In legacy mode, all wheel events go to canvas for zoom
+    if (!isStandardNavMode.value) {
+      event.preventDefault()
+      forwardEventToCanvas(event)
+      return
+    }
+
+    // Otherwise, let the component handle it normally
+  }
+
+  /**
+   * Forwards an event to the LiteGraph canvas
+   */
+  const forwardEventToCanvas = (
+    event: WheelEvent | PointerEvent | MouseEvent
+  ) => {
+    const canvasEl = app.canvas?.canvas
+    if (!canvasEl) return
+
+    // Create new event with same properties
+    const EventConstructor = event.constructor as typeof WheelEvent
+    const newEvent = new EventConstructor(event.type, event)
+    canvasEl.dispatchEvent(newEvent)
+  }
+
+  return {
+    handleWheel,
+    forwardEventToCanvas
+  }
+}
diff --git a/tests-ui/tests/composables/graph/useCanvasInteractions.test.ts b/tests-ui/tests/composables/graph/useCanvasInteractions.test.ts
new file mode 100644
index 000000000..589b3d171
--- /dev/null
+++ b/tests-ui/tests/composables/graph/useCanvasInteractions.test.ts
@@ -0,0 +1,126 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { useCanvasInteractions } from '@/composables/graph/useCanvasInteractions'
+import { app } from '@/scripts/app'
+import * as settingStore from '@/stores/settingStore'
+
+// Mock the app and canvas
+vi.mock('@/scripts/app', () => ({
+  app: {
+    canvas: {
+      canvas: null as HTMLCanvasElement | null
+    }
+  }
+}))
+
+// Mock the setting store
+vi.mock('@/stores/settingStore', () => ({
+  useSettingStore: vi.fn()
+}))
+
+describe('useCanvasInteractions', () => {
+  let mockCanvas: HTMLCanvasElement
+  let mockSettingStore: { get: ReturnType<typeof vi.fn> }
+  let canvasInteractions: ReturnType<typeof useCanvasInteractions>
+
+  beforeEach(() => {
+    // Clear mocks
+    vi.clearAllMocks()
+
+    // Create mock canvas element
+    mockCanvas = document.createElement('canvas')
+    mockCanvas.dispatchEvent = vi.fn()
+    app.canvas!.canvas = mockCanvas
+
+    // Mock setting store
+    mockSettingStore = { get: vi.fn() }
+    vi.mocked(settingStore.useSettingStore).mockReturnValue(
+      mockSettingStore as any
+    )
+
+    canvasInteractions = useCanvasInteractions()
+  })
+
+  describe('handleWheel', () => {
+    it('should check navigation mode from settings', () => {
+      mockSettingStore.get.mockReturnValue('standard')
+
+      const wheelEvent = new WheelEvent('wheel', {
+        ctrlKey: true,
+        deltaY: -100
+      })
+
+      canvasInteractions.handleWheel(wheelEvent)
+
+      expect(mockSettingStore.get).toHaveBeenCalledWith(
+        'Comfy.Canvas.NavigationMode'
+      )
+    })
+
+    it('should not forward regular wheel events in standard mode', () => {
+      mockSettingStore.get.mockReturnValue('standard')
+
+      const wheelEvent = new WheelEvent('wheel', {
+        deltaY: -100
+      })
+
+      canvasInteractions.handleWheel(wheelEvent)
+
+      expect(mockCanvas.dispatchEvent).not.toHaveBeenCalled()
+    })
+
+    it('should forward all wheel events to canvas in legacy mode', () => {
+      mockSettingStore.get.mockReturnValue('legacy')
+
+      const wheelEvent = new WheelEvent('wheel', {
+        deltaY: -100,
+        cancelable: true
+      })
+
+      canvasInteractions.handleWheel(wheelEvent)
+
+      expect(mockCanvas.dispatchEvent).toHaveBeenCalled()
+    })
+
+    it('should handle missing canvas gracefully', () => {
+      ;(app.canvas as any).canvas = null
+      mockSettingStore.get.mockReturnValue('standard')
+
+      const wheelEvent = new WheelEvent('wheel', {
+        ctrlKey: true,
+        deltaY: -100
+      })
+
+      expect(() => {
+        canvasInteractions.handleWheel(wheelEvent)
+      }).not.toThrow()
+    })
+  })
+
+  describe('forwardEventToCanvas', () => {
+    it('should dispatch event to canvas element', () => {
+      const wheelEvent = new WheelEvent('wheel', {
+        deltaY: -100,
+        ctrlKey: true
+      })
+
+      canvasInteractions.forwardEventToCanvas(wheelEvent)
+
+      expect(mockCanvas.dispatchEvent).toHaveBeenCalledWith(
+        expect.any(WheelEvent)
+      )
+    })
+
+    it('should handle missing canvas gracefully', () => {
+      ;(app.canvas as any).canvas = null
+
+      const wheelEvent = new WheelEvent('wheel', {
+        deltaY: -100
+      })
+
+      expect(() => {
+        canvasInteractions.forwardEventToCanvas(wheelEvent)
+      }).not.toThrow()
+    })
+  })
+})