Feature: z-image + metadata node by Pfannkuchensack · Pull Request #8733

Feature: z-image + metadata node by Pfannkuchensack · Pull Request #8733 · invoke-ai/InvokeAI

and others added 15 commits

December 26, 2025 20:53

Add support for alternative diffusers Flow Matching schedulers:
- Euler (default, 1st order)
- Heun (2nd order, better quality, 2x slower)
- LCM (optimized for few steps)

Backend:
- Add schedulers.py with scheduler type definitions and class mapping
- Modify denoise.py to accept optional scheduler parameter
- Add scheduler InputField to flux_denoise invocation (v4.2.0)

Frontend:
- Add fluxScheduler to Redux state and paramsSlice
- Create ParamFluxScheduler component for Linear UI
- Add scheduler to buildFLUXGraph for generation

Add support for alternative diffusers Flow Matching schedulers for Z-Image:
- Euler (default) - 1st order, optimized for Z-Image-Turbo (8 steps)
- Heun (2nd order) - Better quality, 2x slower
- LCM - Optimized for few-step generation

Backend:
- Extend schedulers.py with Z-Image scheduler types and mapping
- Add scheduler InputField to z_image_denoise invocation (v1.3.0)
- Refactor denoising loop to support diffusers schedulers

Frontend:
- Add zImageScheduler to Redux state in paramsSlice
- Create ParamZImageScheduler component for Linear UI
- Add scheduler to buildZImageGraph for generation

LCM scheduler may have more internal timesteps than user-facing steps,
causing user_step to exceed total_steps. This resulted in progress
percentage > 1.0, which caused a pydantic validation error.

Fix: Only call step_callback when user_step <= total_steps.

…ount

Remove the initial step_callback at step=0 to match SD/SDXL behavior.
Previously Flux/Z-Image showed N+1 steps (step 0 + N denoising steps),
while SD/SDXL showed only N steps. Now all models display N steps
consistently in the server log.

- Handle LCM scheduler by using num_inference_steps instead of custom sigmas
- Fix progress bar to show user-facing steps instead of internal scheduler steps
- Pass scheduler parameter to Z-Image denoise node in graph builder
- Add model-aware metadata recall for Flux and Z-Image schedulers

Add ZImageDenoiseMetaInvocation that extends ZImageDenoiseInvocation
with metadata output for image recall. Captures generation parameters
including steps, guidance, scheduler, seed, model, and LoRAs.

Move Scheduler handler after MainModel in ImageMetadataHandlers so that
base-dependent recall logic (z-image scheduler) works correctly. The
Scheduler handler checks `base === 'z-image'` before dispatching the
z-image scheduler action, but this check failed when Scheduler ran
before MainModel was recalled.

Instead of disabling mutually exclusive model selectors, automatically
clear conflicting models when a new selection is made. This applies to
VAE, Qwen3 Encoder, and Qwen3 Source selectors - selecting one now
clears the others. Also applies same logic during metadata recall.