diff --git a/TRACKING.md b/TRACKING.md
index 53ed4d1d..485aa786 100644
--- a/TRACKING.md
+++ b/TRACKING.md
@@ -138,3 +138,4 @@
 - 2026-06-17 前端拆分第二十阶段：新增 `ImageCanvasMetadataModalView`，把图片信息弹窗从主视图抽出，承载图片类型、生成输入、参考图、模型、分辨率、Provider、Task 和 Object 信息渲染；主视图只保留 `metadataLayer` 状态和关闭回调。同步修复未登录进入编辑器时项目 / 素材接口抢跑 401、`重置画布视图` 点击事件误传给适合视图函数的问题。新增组件单测覆盖生成图 metadata、上传图 fallback 和关闭回调，新增 hook / 主视图测试覆盖未登录不请求受保护素材 / 工程数据和重置按钮回归；主视图从 1405 行降至 1337 行。验证命令：`npm run test -- src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx`、`npm run typecheck`、`npm run check:encoding`、`git diff --check`；浏览器回归：`http://127.0.0.1:10003/editor/canvas` 清空会话后直接弹出 `账号入口`，且未登录状态下没有发起 `/api/editor/*` 请求；登录临时开发账号后 `重置画布视图` 无控制台错误，`画布背景设置` 保持 Lovart 式白色浮层，点击 `暖灰` 后 viewport 背景为 `rgb(243, 240, 234)`，上传素材可加入画布，右上角图片信息按钮可打开不透明白底元数据弹窗，关闭后 `AI画布工具栏` 仍可见。
 - 2026-06-17 前端拆分第二十一阶段：新增 `useImageCanvasKeyboardShortcuts`，把 Ctrl / Cmd + Z 撤销、Ctrl / Cmd + Shift + Z 重做、Shift 状态、Backspace / Delete 删除、Escape 关闭临时面板和 Space 临时抓手从主视图抽出；主视图继续注入图层删除、生成对话框、快速编辑和 chrome 面板 setter。新增 hook 单测覆盖输入框忽略快捷键、删除选中图层、删除生成占位、Escape 保留生成中面板、Space 和 Shift；主视图从 1337 行降至 1250 行。验证命令：`npm run test -- src/components/image-editor/useImageCanvasKeyboardShortcuts.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/useImageCanvasCanvasDropWorkflow.test.tsx src/components/image-editor/useImageCanvasStageInteractions.test.tsx src/components/image-editor/useImageCanvasViewportControls.test.tsx src/components/image-editor/ImageCanvasInteractionModel.test.ts src/components/image-editor/useCanvasHistory.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx`、`npm run typecheck`、`npm run check:encoding`、`git diff --check`；浏览器回归：`http://127.0.0.1:10003/editor/canvas` 未登录直接弹出 `账号入口` 且未抢跑 `/api/editor/*`，登录后 `/api/editor/assets/library` 和 `/api/editor/projects/recent` 为 200，`AI画布工具栏` 与 `画布面板入口` 可见，viewport 背景为 `rgb(248, 250, 252)` 且 `background-image: none`；按住 Space 从 `文字工具` 临时切到 `抓手工具`，松开恢复 `文字工具`；`画布背景设置` 点击 `暖灰` 后背景变为 `rgb(243, 240, 234)`；点击 `生成工具` 后 `Image Generator` 占位框、`生成图片` 对话框和 `AI画布工具栏` 同时可见，登录后控制台无前端 error。
 - 2026-06-17 前端拆分第二十二阶段：新增 `useImageCanvasAssetPointerDragBridge`，把素材卡片 pointer 拖拽到画布 / 文件夹的全局监听、拖拽激活、画布 drop 提示、文件夹高亮、移动素材、加入画布和点击抑制从主视图抽出；主视图继续负责素材库事实、画布建层、历史和工程资源持久化。同步恢复 `账号入口` 认证弹窗 portal 渲染，避免全屏画布遮住登录弹窗；`画布背景设置` 调整为独立白色浮层，包含当前色、色域、色相、自定义颜色、预设网格、HEX 输入和恢复默认。验证命令：`npm run test -- src/components/image-editor/useImageCanvasAssetPointerDragBridge.test.tsx src/components/image-editor/useImageCanvasKeyboardShortcuts.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/useImageCanvasCanvasDropWorkflow.test.tsx src/components/image-editor/useImageCanvasStageInteractions.test.tsx src/components/image-editor/useImageCanvasViewportControls.test.tsx src/components/image-editor/ImageCanvasInteractionModel.test.ts src/components/image-editor/useCanvasHistory.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx src/components/auth/PlatformAuthModalShell.test.tsx src/components/auth/AuthGate.test.tsx`、`npm run typecheck`、`npm run check:encoding`、`git diff --check`；浏览器回归：`http://127.0.0.1:10007/editor/canvas` 未登录打开直接显示 `账号入口`；登录临时开发账号后 `画布背景设置` 显示当前色、色域、色相、自定义颜色、预设、HEX 和恢复默认，点击 `暖灰` 后 viewport 背景为 `rgb(243, 240, 234)` 且 `background-image: none`；上传图片进入 `项目素材`，真实 pointer 拖拽素材到画布后图层数从 0 到 1 且 `AI画布工具栏` 保持可见；新建 `SmokeFolder` 后真实 pointer 拖拽素材到文件夹，`项目素材` 变 0、`SmokeFolder` 变 1，素材执行移动而非拷贝。控制台仅有未登录 refresh 401，登录后编辑器 API 均为 200。
+- 2026-06-17 前端拆分第二十三阶段：新增 `ImageCanvasOverlayModel`，把生成输入框锚定、图标素材生成面板宽度、选中图片工具栏边界、快速编辑面板和角色动画面板定位从主视图抽出为纯模型；主视图继续保留生成 / quick edit / 角色动画状态机和舞台编排。新增模型单测覆盖锚定优先级、生成中隐藏、icon 宽度、工具栏 clamp、quick edit / 角色动画边界和生成 dialog 模式识别；主视图从 1182 行降至 1133 行。验证命令：`npm run test -- src/components/image-editor/ImageCanvasOverlayModel.test.ts src/components/image-editor/ImageCanvasEditorView.test.tsx`、`npm run test -- src/components/image-editor/useImageCanvasAssetPointerDragBridge.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/useImageCanvasGenerationWorkflow.test.tsx`、`npm run test -- src/components/image-editor/ImageCanvasOverlayModel.test.ts src/components/image-editor/useImageCanvasAssetPointerDragBridge.test.tsx src/components/image-editor/useImageCanvasKeyboardShortcuts.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/useImageCanvasCanvasDropWorkflow.test.tsx src/components/image-editor/useImageCanvasStageInteractions.test.tsx src/components/image-editor/useImageCanvasViewportControls.test.tsx src/components/image-editor/ImageCanvasInteractionModel.test.ts src/components/image-editor/useCanvasHistory.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/useImageCanvasGenerationWorkflow.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx src/components/auth/PlatformAuthModalShell.test.tsx src/components/auth/AuthGate.test.tsx`、`npm run typecheck`、`npm run check:encoding`、`git diff --check`；浏览器回归：`http://127.0.0.1:10007/editor/canvas` 未登录打开显示 `账号入口`，登录后 `画布背景设置` 点击 `暖灰` 后 viewport 背景为 `rgb(243, 240, 234)` 且 `background-image: none`，点击 `生成工具` 后 `Image Generator`、`生成图片` 对话框和 `AI画布工具栏` 均可见；素材库已有素材真实 pointer 拖入画布后图层数从 0 到 1，工具栏保持可见，截图留存于 `output/playwright/editor-overlay-model-regression-20260617.png`。
diff --git a/docs/technical/【前端架构】图片画布编辑器前端拆分计划-2026-06-17.md b/docs/technical/【前端架构】图片画布编辑器前端拆分计划-2026-06-17.md
index 7894715c..2ca1b736 100644
--- a/docs/technical/【前端架构】图片画布编辑器前端拆分计划-2026-06-17.md
+++ b/docs/technical/【前端架构】图片画布编辑器前端拆分计划-2026-06-17.md
@@ -191,14 +191,22 @@
   - 该 hook 用独立单测覆盖拖拽激活、文件夹 drop、画布 drop、非激活拖拽清理和 pointer cancel 完成路径；主视图 DOM 测试继续覆盖真实素材库拖到画布和拖到文件夹的集成链路。
   - 本阶段同步恢复认证弹窗使用 portal 渲染，避免 `/editor/canvas` 这类全屏画布内容把 `账号入口` 遮住；同时把画布背景设置面板调整为独立白色浮层，包含当前色、色域、色相、自定义颜色、预设网格、HEX 输入和恢复默认。
 
+## 第二十三阶段模块
+
+- `ImageCanvasOverlayModel.ts`
+  - 承载画布浮层定位纯规则：生成输入框锚定、图标素材生成面板横向扩宽、选中图片工具栏边界限制、快速编辑面板定位和角色动画面板定位。
+  - 主视图继续负责生成对象、quick edit、角色动画、视口和图层状态编排，只把可纯函数验证的屏幕坐标计算移出，避免后续调整 Lovart 式浮层时继续在主视图里散落坐标公式。
+  - 该模块用独立单测覆盖生成结果优先锚定、生成中 / 手动关闭隐藏输入框、icon 描述项宽度、图片工具栏 clamp、quick edit 和角色动画面板边界，以及画布生成 dialog 模式识别。
+  - 本阶段主视图从 1182 行降至 1133 行；下一步若继续拆分，可在该模型基础上抽更大的 `useImageCanvasStageController`，承接舞台派生状态、右键菜单和工具切换胶水。
+
 ## 后续阶段
 
 - 后续可继续选择更高内聚的交互 workflow 或持久化边界，不再把生成链路继续拆成浅层 wrapper。
-- 右键菜单定位、工程资源持久化和历史捕获仍在主视图编排，拆分前需要先确认不会破坏多生成对象同时存在、完成时读取最新占位框、素材拖拽上传位置和角色动画优先传 `objectKey` 的历史保护规则。
+- 右键菜单定位、工程资源持久化、舞台派生状态和历史捕获仍在主视图编排，拆分前需要先确认不会破坏多生成对象同时存在、完成时读取最新占位框、素材拖拽上传位置和角色动画优先传 `objectKey` 的历史保护规则。
 
 ## 验证计划
 
-- `npm run test -- src/components/image-editor/useImageCanvasAssetPointerDragBridge.test.tsx src/components/image-editor/useImageCanvasKeyboardShortcuts.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/useImageCanvasCanvasDropWorkflow.test.tsx src/components/image-editor/useImageCanvasStageInteractions.test.tsx src/components/image-editor/useImageCanvasViewportControls.test.tsx src/components/image-editor/ImageCanvasInteractionModel.test.ts src/components/image-editor/useCanvasHistory.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx src/components/auth/PlatformAuthModalShell.test.tsx src/components/auth/AuthGate.test.tsx`
+- `npm run test -- src/components/image-editor/ImageCanvasOverlayModel.test.ts src/components/image-editor/useImageCanvasAssetPointerDragBridge.test.tsx src/components/image-editor/useImageCanvasKeyboardShortcuts.test.tsx src/components/image-editor/ImageCanvasMetadataModalView.test.tsx src/components/image-editor/useImageCanvasAssetLibrary.test.tsx src/components/image-editor/useImageCanvasProjectPersistence.test.tsx src/components/image-editor/useImageCanvasCanvasDropWorkflow.test.tsx src/components/image-editor/useImageCanvasStageInteractions.test.tsx src/components/image-editor/useImageCanvasViewportControls.test.tsx src/components/image-editor/ImageCanvasInteractionModel.test.ts src/components/image-editor/useCanvasHistory.test.tsx src/components/image-editor/useImageCanvasEditorChrome.test.tsx src/components/image-editor/ImageCanvasEditorView.test.tsx src/components/auth/PlatformAuthModalShell.test.tsx src/components/auth/AuthGate.test.tsx`
 - `npm run typecheck`
 - `npm run check:encoding`
 - `git diff --check`
diff --git a/src/components/image-editor/ImageCanvasEditorView.tsx b/src/components/image-editor/ImageCanvasEditorView.tsx
index 0678c404..b534a315 100644
--- a/src/components/image-editor/ImageCanvasEditorView.tsx
+++ b/src/components/image-editor/ImageCanvasEditorView.tsx
@@ -1,6 +1,5 @@
 import { Check, ChevronLeft, Download, Pencil, X } from 'lucide-react';
 import {
-  type CSSProperties,
   type MouseEvent as ReactMouseEvent,
   useCallback,
   useEffect,
@@ -22,22 +21,25 @@ import {
 import { ImageCanvasSidebarView } from './ImageCanvasSidebarView';
 import { ImageCanvasStageView } from './ImageCanvasStageView';
 import {
-  TOOLBAR_HALF_WIDTH,
-  clamp,
   createLayerFromAsset,
   isGeneratedLayer,
   isLayerLinkedToAsset,
   resolveContextMenuPosition,
-  serializeLayer,
 } from './ImageCanvasEditorModel';
 import {
-  ICON_COMPOSER_HORIZONTAL_CHROME_REM,
-  ICON_COMPOSER_MIN_WIDTH_REM,
-  ICON_DESCRIPTION_CARD_WIDTH_REM,
   getGenerationFrameAriaLabel,
   getGenerationFrameLabel,
   getLayerKindLabel,
 } from './ImageCanvasGenerationModel';
+import {
+  isCanvasGenerationComposerVisible,
+  resolveCharacterAnimationPanelStyle,
+  resolveGenerationAnchor,
+  resolveGenerationComposerStyle,
+  resolveIconComposerStyle,
+  resolveQuickEditPanelStyle,
+  resolveSelectedToolbarStyle,
+} from './ImageCanvasOverlayModel';
 import type {
   AssetPointerDragState,
   CanvasContextMenuState,
@@ -302,36 +304,21 @@ export function ImageCanvasEditorView() {
     [activeCanvasGenerationDialog, layers],
   );
   const generationAnchor = activeCanvasGenerationDialog
-    ? (activeGenerationLayer ??
-      activeCanvasGenerationDialog.placeholder ??
-      null)
-    : null;
-  const generationComposerStyle =
-    activeCanvasGenerationDialog?.status !== 'generating' &&
-    activeCanvasGenerationDialog?.composerOpen !== false &&
-    generationAnchor
-      ? {
-          left:
-            viewport.x +
-            (generationAnchor.x + generationAnchor.width / 2) * viewport.scale,
-          top:
-            viewport.y +
-            (generationAnchor.y + generationAnchor.height) * viewport.scale +
-            10,
-        }
-      : null;
-  const selectedToolbarStyle = selectedLayer
-    ? {
-        left: clamp(
-          viewport.x +
-            selectedLayer.x * viewport.scale +
-            (selectedLayer.width * viewport.scale) / 2,
-          TOOLBAR_HALF_WIDTH,
-          Math.max(TOOLBAR_HALF_WIDTH, canvasSize.width - TOOLBAR_HALF_WIDTH),
-        ),
-        top: Math.max(10, viewport.y + selectedLayer.y * viewport.scale - 12),
-      }
+    ? resolveGenerationAnchor({
+        dialog: activeCanvasGenerationDialog,
+        generatedLayer: activeGenerationLayer,
+      })
     : null;
+  const generationComposerStyle = resolveGenerationComposerStyle({
+    dialog: activeCanvasGenerationDialog,
+    anchor: generationAnchor,
+    viewport,
+  });
+  const selectedToolbarStyle = resolveSelectedToolbarStyle({
+    selectedLayer,
+    viewport,
+    canvasSize,
+  });
   const imageContextMenuLayer = imageContextMenu
     ? (layers.find((layer) => layer.id === imageContextMenu.layerId) ?? null)
     : null;
@@ -396,10 +383,7 @@ export function ImageCanvasEditorView() {
     setSelectedLayerIds(layerId ? [layerId] : []);
     if (layerId) {
       setGenerateDialog((currentDialog) =>
-        currentDialog?.mode === 'generate' ||
-        currentDialog?.mode === 'spec' ||
-        currentDialog?.mode === 'character' ||
-        currentDialog?.mode === 'icon'
+        isCanvasGenerationComposerVisible(currentDialog)
           ? {
               ...currentDialog,
               composerOpen: false,
@@ -509,56 +493,23 @@ export function ImageCanvasEditorView() {
     closeGenerateComposer,
     clearDeletedLayerGenerationState,
   } = generationWorkflow;
-  const iconComposerStyle: CSSProperties | null =
-    activeCanvasGenerationDialog?.mode === 'icon' && generationComposerStyle
-      ? {
-          ...generationComposerStyle,
-          width: `${Math.max(
-            ICON_COMPOSER_MIN_WIDTH_REM,
-            ICON_COMPOSER_HORIZONTAL_CHROME_REM +
-              iconDescriptionValues.length * ICON_DESCRIPTION_CARD_WIDTH_REM,
-          ).toFixed(1)}rem`,
-        }
-      : null;
-  const quickEditPanelStyle =
-    quickEditPanel && quickEditSourceLayer
-      ? {
-          left: clamp(
-            viewport.x +
-              (quickEditSourceLayer.x + quickEditSourceLayer.width / 2) *
-                viewport.scale,
-            12,
-            Math.max(12, canvasSize.width - 12),
-          ),
-          top: clamp(
-            viewport.y +
-              (quickEditSourceLayer.y + quickEditSourceLayer.height) *
-                viewport.scale +
-              12,
-            12,
-            Math.max(12, canvasSize.height - 360),
-          ),
-        }
-      : null;
-  const characterAnimationPanelStyle =
-    characterAnimationPanel && characterAnimationSourceLayer
-      ? {
-          left: clamp(
-            viewport.x +
-              (characterAnimationSourceLayer.x +
-                characterAnimationSourceLayer.width) *
-                viewport.scale +
-              12,
-            12,
-            Math.max(12, canvasSize.width - 364),
-          ),
-          top: clamp(
-            viewport.y + characterAnimationSourceLayer.y * viewport.scale,
-            12,
-            Math.max(12, canvasSize.height - 520),
-          ),
-        }
-      : null;
+  const iconComposerStyle = resolveIconComposerStyle({
+    dialog: activeCanvasGenerationDialog,
+    composerStyle: generationComposerStyle,
+    iconDescriptionCount: iconDescriptionValues.length,
+  });
+  const quickEditPanelStyle = resolveQuickEditPanelStyle({
+    panel: quickEditPanel,
+    sourceLayer: quickEditSourceLayer,
+    viewport,
+    canvasSize,
+  });
+  const characterAnimationPanelStyle = resolveCharacterAnimationPanelStyle({
+    panel: characterAnimationPanel,
+    sourceLayer: characterAnimationSourceLayer,
+    viewport,
+    canvasSize,
+  });
   const {
     canvasClipboard,
     pasteCanvasClipboard,
diff --git a/src/components/image-editor/ImageCanvasOverlayModel.test.ts b/src/components/image-editor/ImageCanvasOverlayModel.test.ts
new file mode 100644
index 00000000..de6bb167
--- /dev/null
+++ b/src/components/image-editor/ImageCanvasOverlayModel.test.ts
@@ -0,0 +1,188 @@
+import { describe, expect, it } from 'vitest';
+
+import type {
+  CanvasGenerationDialogState,
+  CanvasLayer,
+  CharacterAnimationPanelState,
+  QuickEditPanelState,
+} from './ImageCanvasEditorTypes';
+import {
+  isCanvasGenerationComposerVisible,
+  resolveCharacterAnimationPanelStyle,
+  resolveGenerationAnchor,
+  resolveGenerationComposerStyle,
+  resolveIconComposerStyle,
+  resolveQuickEditPanelStyle,
+  resolveSelectedToolbarStyle,
+} from './ImageCanvasOverlayModel';
+
+function createLayer(overrides: Partial<CanvasLayer> = {}): CanvasLayer {
+  return {
+    id: 'layer-a',
+    resourceId: 'resource-a',
+    title: '图层A',
+    src: 'data:image/png;base64,layer',
+    x: 100,
+    y: 80,
+    width: 240,
+    height: 120,
+    originalWidth: 240,
+    originalHeight: 120,
+    zIndex: 1,
+    sourceType: 'uploaded',
+    ...overrides,
+  };
+}
+
+function createDialog(
+  overrides: Partial<CanvasGenerationDialogState> = {},
+): CanvasGenerationDialogState {
+  return {
+    id: 'dialog-a',
+    mode: 'generate',
+    prompt: '',
+    status: 'idle',
+    placeholder: {
+      x: 300,
+      y: 200,
+      width: 360,
+      height: 260,
+      originalWidth: 1024,
+      originalHeight: 1024,
+    },
+    ...overrides,
+  };
+}
+
+describe('ImageCanvasOverlayModel', () => {
+  it('anchors generation composer to generated layers before placeholders', () => {
+    const generatedLayer = createLayer({ x: 40, y: 60, width: 320, height: 180 });
+    const dialog = createDialog({ generatedLayerId: generatedLayer.id });
+    const anchor = resolveGenerationAnchor({ dialog, generatedLayer });
+
+    expect(anchor).toBe(generatedLayer);
+    expect(
+      resolveGenerationComposerStyle({
+        dialog,
+        anchor,
+        viewport: { x: 10, y: 20, scale: 2 },
+      }),
+    ).toEqual({
+      left: 410,
+      top: 510,
+    });
+  });
+
+  it('hides generation composer while generating or explicitly closed', () => {
+    const placeholder = createDialog().placeholder ?? null;
+
+    expect(
+      resolveGenerationComposerStyle({
+        dialog: createDialog({ status: 'generating' }),
+        anchor: placeholder,
+        viewport: { x: 0, y: 0, scale: 1 },
+      }),
+    ).toBeNull();
+    expect(
+      resolveGenerationComposerStyle({
+        dialog: createDialog({ composerOpen: false }),
+        anchor: placeholder,
+        viewport: { x: 0, y: 0, scale: 1 },
+      }),
+    ).toBeNull();
+  });
+
+  it('expands icon composer width by description count', () => {
+    expect(
+      resolveIconComposerStyle({
+        dialog: createDialog({ mode: 'icon' }),
+        composerStyle: { left: 100, top: 200 },
+        iconDescriptionCount: 6,
+      }),
+    ).toEqual({
+      left: 100,
+      top: 200,
+      width: '52.8rem',
+    });
+
+    expect(
+      resolveIconComposerStyle({
+        dialog: createDialog({ mode: 'generate' }),
+        composerStyle: { left: 100, top: 200 },
+        iconDescriptionCount: 6,
+      }),
+    ).toBeNull();
+  });
+
+  it('keeps selected layer toolbar inside the canvas width', () => {
+    expect(
+      resolveSelectedToolbarStyle({
+        selectedLayer: createLayer({ x: -500, y: -100 }),
+        viewport: { x: 0, y: 0, scale: 1 },
+        canvasSize: { width: 900, height: 640 },
+      }),
+    ).toEqual({ left: 132, top: 10 });
+
+    expect(
+      resolveSelectedToolbarStyle({
+        selectedLayer: createLayer({ x: 1200, y: 100 }),
+        viewport: { x: 0, y: 0, scale: 1 },
+        canvasSize: { width: 900, height: 640 },
+      }),
+    ).toEqual({ left: 768, top: 88 });
+  });
+
+  it('positions quick edit and character animation panels with viewport bounds', () => {
+    const sourceLayer = createLayer({ x: 740, y: 460, width: 240, height: 180 });
+    const quickEditPanel: QuickEditPanelState = {
+      sourceLayerId: sourceLayer.id,
+      prompt: '',
+      size: '1024x1024',
+      model: 'gpt-image-2',
+      status: 'idle',
+    };
+    const characterPanel: CharacterAnimationPanelState = {
+      sourceLayerId: sourceLayer.id,
+      promptText: '',
+      resolution: '480p',
+      ratio: 'same',
+      frameCount: 32,
+      durationSeconds: 4,
+      status: 'idle',
+    };
+
+    expect(
+      resolveQuickEditPanelStyle({
+        panel: quickEditPanel,
+        sourceLayer,
+        viewport: { x: 20, y: 10, scale: 1 },
+        canvasSize: { width: 900, height: 640 },
+      }),
+    ).toEqual({ left: 880, top: 280 });
+    expect(
+      resolveCharacterAnimationPanelStyle({
+        panel: characterPanel,
+        sourceLayer,
+        viewport: { x: 20, y: 10, scale: 1 },
+        canvasSize: { width: 900, height: 640 },
+      }),
+    ).toEqual({ left: 536, top: 120 });
+  });
+
+  it('recognizes canvas generation composer dialog modes', () => {
+    expect(isCanvasGenerationComposerVisible(createDialog({ mode: 'generate' }))).toBe(
+      true,
+    );
+    expect(isCanvasGenerationComposerVisible(createDialog({ mode: 'spec' }))).toBe(
+      true,
+    );
+    expect(
+      isCanvasGenerationComposerVisible({
+        mode: 'edit',
+        prompt: '',
+        status: 'idle',
+      }),
+    ).toBe(false);
+    expect(isCanvasGenerationComposerVisible(null)).toBe(false);
+  });
+});
diff --git a/src/components/image-editor/ImageCanvasOverlayModel.ts b/src/components/image-editor/ImageCanvasOverlayModel.ts
new file mode 100644
index 00000000..59492c8b
--- /dev/null
+++ b/src/components/image-editor/ImageCanvasOverlayModel.ts
@@ -0,0 +1,188 @@
+import {
+  TOOLBAR_HALF_WIDTH,
+  clamp,
+} from './ImageCanvasEditorModel';
+import {
+  ICON_COMPOSER_HORIZONTAL_CHROME_REM,
+  ICON_COMPOSER_MIN_WIDTH_REM,
+  ICON_DESCRIPTION_CARD_WIDTH_REM,
+} from './ImageCanvasGenerationModel';
+import type {
+  CanvasGenerationDialogMode,
+  CanvasGenerationDialogState,
+  CanvasLayer,
+  CanvasViewport,
+  CharacterAnimationPanelState,
+  GenerateDialogState,
+  QuickEditPanelState,
+} from './ImageCanvasEditorTypes';
+
+type CanvasSize = {
+  width: number;
+  height: number;
+};
+
+type OverlayAnchor = Pick<CanvasLayer, 'x' | 'y' | 'width' | 'height'>;
+
+export type CanvasOverlayStyle = {
+  left: number;
+  top: number;
+};
+
+export type CanvasComposerOverlayStyle = CanvasOverlayStyle & {
+  width?: string;
+};
+
+export function resolveGenerationAnchor({
+  dialog,
+  generatedLayer,
+}: {
+  dialog: CanvasGenerationDialogState | null;
+  generatedLayer: CanvasLayer | null;
+}) {
+  if (!dialog) {
+    return null;
+  }
+  return generatedLayer ?? dialog.placeholder ?? null;
+}
+
+export function resolveGenerationComposerStyle({
+  dialog,
+  anchor,
+  viewport,
+}: {
+  dialog: CanvasGenerationDialogState | null;
+  anchor: OverlayAnchor | null;
+  viewport: CanvasViewport;
+}): CanvasOverlayStyle | null {
+  if (
+    !dialog ||
+    dialog.status === 'generating' ||
+    dialog.composerOpen === false ||
+    !anchor
+  ) {
+    return null;
+  }
+  return {
+    left: viewport.x + (anchor.x + anchor.width / 2) * viewport.scale,
+    top: viewport.y + (anchor.y + anchor.height) * viewport.scale + 10,
+  };
+}
+
+export function resolveIconComposerStyle({
+  dialog,
+  composerStyle,
+  iconDescriptionCount,
+}: {
+  dialog: CanvasGenerationDialogState | null;
+  composerStyle: CanvasOverlayStyle | null;
+  iconDescriptionCount: number;
+}): CanvasComposerOverlayStyle | null {
+  if (dialog?.mode !== 'icon' || !composerStyle) {
+    return null;
+  }
+  return {
+    ...composerStyle,
+    width: `${Math.max(
+      ICON_COMPOSER_MIN_WIDTH_REM,
+      ICON_COMPOSER_HORIZONTAL_CHROME_REM +
+        iconDescriptionCount * ICON_DESCRIPTION_CARD_WIDTH_REM,
+    ).toFixed(1)}rem`,
+  };
+}
+
+export function resolveSelectedToolbarStyle({
+  selectedLayer,
+  viewport,
+  canvasSize,
+}: {
+  selectedLayer: CanvasLayer | null;
+  viewport: CanvasViewport;
+  canvasSize: CanvasSize;
+}): CanvasOverlayStyle | null {
+  if (!selectedLayer) {
+    return null;
+  }
+  return {
+    left: clamp(
+      viewport.x +
+        selectedLayer.x * viewport.scale +
+        (selectedLayer.width * viewport.scale) / 2,
+      TOOLBAR_HALF_WIDTH,
+      Math.max(TOOLBAR_HALF_WIDTH, canvasSize.width - TOOLBAR_HALF_WIDTH),
+    ),
+    top: Math.max(10, viewport.y + selectedLayer.y * viewport.scale - 12),
+  };
+}
+
+export function resolveQuickEditPanelStyle({
+  panel,
+  sourceLayer,
+  viewport,
+  canvasSize,
+}: {
+  panel: QuickEditPanelState | null;
+  sourceLayer: CanvasLayer | null;
+  viewport: CanvasViewport;
+  canvasSize: CanvasSize;
+}): CanvasOverlayStyle | null {
+  if (!panel || !sourceLayer) {
+    return null;
+  }
+  return {
+    left: clamp(
+      viewport.x +
+        (sourceLayer.x + sourceLayer.width / 2) * viewport.scale,
+      12,
+      Math.max(12, canvasSize.width - 12),
+    ),
+    top: clamp(
+      viewport.y +
+        (sourceLayer.y + sourceLayer.height) * viewport.scale +
+        12,
+      12,
+      Math.max(12, canvasSize.height - 360),
+    ),
+  };
+}
+
+export function resolveCharacterAnimationPanelStyle({
+  panel,
+  sourceLayer,
+  viewport,
+  canvasSize,
+}: {
+  panel: CharacterAnimationPanelState | null;
+  sourceLayer: CanvasLayer | null;
+  viewport: CanvasViewport;
+  canvasSize: CanvasSize;
+}): CanvasOverlayStyle | null {
+  if (!panel || !sourceLayer) {
+    return null;
+  }
+  return {
+    left: clamp(
+      viewport.x +
+        (sourceLayer.x + sourceLayer.width) * viewport.scale +
+        12,
+      12,
+      Math.max(12, canvasSize.width - 364),
+    ),
+    top: clamp(
+      viewport.y + sourceLayer.y * viewport.scale,
+      12,
+      Math.max(12, canvasSize.height - 520),
+    ),
+  };
+}
+
+export function isCanvasGenerationComposerVisible(
+  dialog: GenerateDialogState | null,
+): dialog is GenerateDialogState & { mode: CanvasGenerationDialogMode } {
+  return (
+    dialog?.mode === 'generate' ||
+    dialog?.mode === 'spec' ||
+    dialog?.mode === 'character' ||
+    dialog?.mode === 'icon'
+  );
+}