feat: add live preview method setting for prompt execution

Allow users to override the preview method (default/none/auto/latent2rgb/taesd)
from frontend settings. 'default' uses the server CLI setting.

Author: ltdrdata

src/composables/useCoreCommands.ts

@@ -480,10 +480,13 @@ export function useCoreCommands(): ComfyCommand[] {
         }
 
         const batchCount = useQueueSettingsStore().batchCount
+        const previewMethod = useSettingStore().get(
+          'Comfy.Execution.PreviewMethod'
+        )
 
         useTelemetry()?.trackWorkflowExecution()
 
-        await app.queuePrompt(0, batchCount)
+        await app.queuePrompt(0, batchCount, undefined, previewMethod)
       }
     },
     {
@@ -503,10 +506,13 @@ export function useCoreCommands(): ComfyCommand[] {
         }
 
         const batchCount = useQueueSettingsStore().batchCount
+        const previewMethod = useSettingStore().get(
+          'Comfy.Execution.PreviewMethod'
+        )
 
         useTelemetry()?.trackWorkflowExecution()
 
-        await app.queuePrompt(-1, batchCount)
+        await app.queuePrompt(-1, batchCount, undefined, previewMethod)
       }
     },
     {
@@ -525,6 +531,9 @@ export function useCoreCommands(): ComfyCommand[] {
         }
 
         const batchCount = useQueueSettingsStore().batchCount
+        const previewMethod = useSettingStore().get(
+          'Comfy.Execution.PreviewMethod'
+        )
         const selectedNodes = getSelectedNodes()
         const selectedOutputNodes = filterOutputNodes(selectedNodes)
 
@@ -552,7 +561,7 @@ export function useCoreCommands(): ComfyCommand[] {
           return
         }
         useTelemetry()?.trackWorkflowExecution()
-        await app.queuePrompt(0, batchCount, executionIds)
+        await app.queuePrompt(0, batchCount, executionIds, previewMethod)
       }
     },
     {

src/locales/en/settings.json

@@ -79,6 +79,17 @@
   "Comfy_EnableWorkflowViewRestore": {
     "name": "Save and restore canvas position and zoom level in workflows"
   },
+  "Comfy_Execution_PreviewMethod": {
+    "name": "Live preview method",
+    "tooltip": "Live preview method during image generation. \"default\" uses the server CLI setting.",
+    "options": {
+      "default": "default",
+      "none": "none",
+      "auto": "auto",
+      "latent2rgb": "latent2rgb",
+      "taesd": "taesd"
+    }
+  },
   "Comfy_FloatRoundingPrecision": {
     "name": "Float widget rounding decimal places [0 = auto].",
     "tooltip": "(requires page reload)"

src/platform/settings/constants/coreSettings.ts

@@ -807,6 +807,17 @@ export const CORE_SETTINGS: SettingParams[] = [
     defaultValue: 64,
     versionAdded: '1.4.12'
   },
+  {
+    id: 'Comfy.Execution.PreviewMethod',
+    category: ['Comfy', 'Execution', 'PreviewMethod'],
+    name: 'Live preview method',
+    tooltip:
+      'Live preview method during image generation. "default" uses the server CLI setting.',
+    type: 'combo',
+    options: ['default', 'none', 'auto', 'latent2rgb', 'taesd'],
+    defaultValue: 'default',
+    versionAdded: '1.35.3'
+  },
   {
     id: 'LiteGraph.Canvas.MaximumFps',
     name: 'Maximum FPS',

src/schemas/apiSchema.ts

@@ -433,6 +433,13 @@ const zSettings = z.object({
   'Comfy.TreeExplorer.ItemPadding': z.number(),
   'Comfy.Validation.Workflows': z.boolean(),
   'Comfy.Workflow.SortNodeIdOnSave': z.boolean(),
+  'Comfy.Execution.PreviewMethod': z.enum([
+    'default',
+    'none',
+    'auto',
+    'latent2rgb',
+    'taesd'
+  ]),
   'Comfy.Workflow.WorkflowTabsPosition': z.enum(['Sidebar', 'Topbar']),
   'Comfy.Node.DoubleClickTitleToEdit': z.boolean(),
   'Comfy.WidgetControlMode': z.enum(['before', 'after']),

src/scripts/api.ts

@@ -89,6 +89,12 @@ interface QueuePromptRequestBody {
      * ```
      */
     api_key_comfy_org?: string
+    /**
+     * Override the preview method for this prompt execution.
+     * Values: 'default' | 'none' | 'auto' | 'latent2rgb' | 'taesd'
+     * 'default' uses the server's CLI setting.
+     */
+    preview_method?: string
   }
   front?: boolean
   number?: number
@@ -104,6 +110,12 @@ interface QueuePromptOptions {
    * Format: Colon-separated path of node IDs (e.g., "123:456:789")
    */
   partialExecutionTargets?: NodeExecutionId[]
+  /**
+   * Override the preview method for this prompt execution.
+   * Values: 'default' | 'none' | 'auto' | 'latent2rgb' | 'taesd'
+   * 'default' uses the server's CLI setting and is not sent to backend.
+   */
+  previewMethod?: string
 }
 
 /** Dictionary of Frontend-generated API calls */
@@ -773,7 +785,11 @@ export class ComfyApi extends EventTarget {
       extra_data: {
         auth_token_comfy_org: this.authToken,
         api_key_comfy_org: this.apiKey,
-        extra_pnginfo: { workflow }
+        extra_pnginfo: { workflow },
+        ...(options?.previewMethod &&
+          options.previewMethod !== 'default' && {
+            preview_method: options.previewMethod
+          })
       }
     }
 

src/scripts/app.ts

@@ -128,6 +128,7 @@ export class ComfyApp {
     number: number
     batchCount: number
     queueNodeIds?: NodeExecutionId[]
+    previewMethod?: string
   }[] = []
   /**
    * If the queue is currently being processed
@@ -1325,9 +1326,10 @@ export class ComfyApp {
   async queuePrompt(
     number: number,
     batchCount: number = 1,
-    queueNodeIds?: NodeExecutionId[]
+    queueNodeIds?: NodeExecutionId[],
+    previewMethod?: string
   ): Promise<boolean> {
-    this.queueItems.push({ number, batchCount, queueNodeIds })
+    this.queueItems.push({ number, batchCount, queueNodeIds, previewMethod })
 
     // Only have one action process the items so each one gets a unique seed correctly
     if (this.processingQueue) {
@@ -1343,7 +1345,8 @@ export class ComfyApp {
 
     try {
       while (this.queueItems.length) {
-        const { number, batchCount, queueNodeIds } = this.queueItems.pop()!
+        const { number, batchCount, queueNodeIds, previewMethod } =
+          this.queueItems.pop()!
 
         for (let i = 0; i < batchCount; i++) {
           // Allow widgets to run callbacks before a prompt has been queued
@@ -1358,7 +1361,8 @@ export class ComfyApp {
             api.authToken = comfyOrgAuthToken
             api.apiKey = comfyOrgApiKey ?? undefined
             const res = await api.queuePrompt(number, p, {
-              partialExecutionTargets: queueNodeIds
+              partialExecutionTargets: queueNodeIds,
+              previewMethod
             })
             delete api.authToken
             delete api.apiKey

src/services/autoQueueService.ts

@@ -4,10 +4,12 @@ import {
   useQueuePendingTaskCountStore,
   useQueueSettingsStore
 } from '@/stores/queueStore'
+import { useSettingStore } from '@/platform/settings/settingStore'
 
 export function setupAutoQueueHandler() {
   const queueCountStore = useQueuePendingTaskCountStore()
   const queueSettingsStore = useQueueSettingsStore()
+  const settingStore = useSettingStore()
 
   let graphHasChanged = false
   let internalCount = 0 // Use an internal counter here so it is instantly updated when re-queuing
@@ -18,7 +20,13 @@ export function setupAutoQueueHandler() {
       } else {
         graphHasChanged = false
         // Queue the prompt in the background
-        void app.queuePrompt(0, queueSettingsStore.batchCount)
+        const previewMethod = settingStore.get('Comfy.Execution.PreviewMethod')
+        void app.queuePrompt(
+          0,
+          queueSettingsStore.batchCount,
+          undefined,
+          previewMethod
+        )
         internalCount++
       }
     }
@@ -33,7 +41,15 @@ export function setupAutoQueueHandler() {
           (queueSettingsStore.mode === 'change' && graphHasChanged)
         ) {
           graphHasChanged = false
-          await app.queuePrompt(0, queueSettingsStore.batchCount)
+          const previewMethod = settingStore.get(
+            'Comfy.Execution.PreviewMethod'
+          )
+          await app.queuePrompt(
+            0,
+            queueSettingsStore.batchCount,
+            undefined,
+            previewMethod
+          )
         }
       }
     },