---
library_name: diffusers
tags:
- modular-diffusers
- diffusers
- qwenimage21
- text-to-image
---
This is a modular diffusion pipeline built with 🧨 Diffusers' modular pipeline framework.

**Pipeline Type**: QwenImage21AutoBlocks

**Description**: Auto Modular pipeline for text-to-image and image-conditioned generation using Qwen-Image 2.1.
- for text-to-image generation, all you need to provide is `prompt`
- for image-conditioned generation, you need to provide `prompt` and `image` (one image or a list)

This pipeline uses a 4-block architecture that can be customized and extended.

## Example Usage

[TODO]

## Pipeline Architecture

This modular pipeline is composed of the following blocks:

1. **text_encoder** (`QwenImage21AutoTextEncoderStep`)
   - Text encoder step that encodes the prompt, together with the condition images when there are any.
2. **vae_encoder** (`QwenImage21AutoVaeEncoderStep`)
   - VAE encoder step that encodes the condition images into their latent representations.
3. **denoise** (`QwenImage21AutoCoreDenoiseStep`)
   - Auto core denoise step that performs the denoising process.
4. **decode** (`QwenImage21DecodeStep`)
   - Step that decodes the latents to RGBA images and postprocesses them 

## Model Components

1. image_processor (`VaeImageProcessor`)
2. text_encoder (`Qwen3VLForConditionalGeneration`)
3. processor (`Qwen3VLProcessor`)
4. guider (`ClassifierFreeGuidance`)
5. vae (`AutoencoderKLQwenImage21`)
6. scheduler (`FlowMatchEulerDiscreteScheduler`)
7. transformer (`QwenImage21Transformer2DModel`) 

## Configuration Parameters

sample_sigmas (default: None): Default sampling grid of the checkpoint, used when `sigmas` is not passed.

## Workflow Input Specification

<details>
<summary><strong>text2image</strong></summary>

- `prompt` (`str`): The prompt or prompts to guide image generation.

</details>

<details>
<summary><strong>image_conditioned</strong></summary>

- `image` (`Image | list`): Reference image(s) for denoising. Can be a single image or list of images.
- `prompt` (`str`): The prompt or prompts to guide image generation.

</details>


## Input/Output Specification

**Inputs:**

- `image` (`Image | list`, *optional*): Reference image(s) for denoising. Can be a single image or list of images.
- `output_resolution` (`int`, *optional*, defaults to `1024`): Target side length used to derive the output size and to resize condition images.
- `prompt` (`str`): The prompt or prompts to guide image generation.
- `negative_prompt` (`str`, *optional*): The prompt or prompts not to guide the image generation.
- `generator` (`Generator`, *optional*): Torch generator for deterministic generation.
- `num_images_per_prompt` (`int`, *optional*, defaults to `1`): The number of images to generate per prompt.
- `height` (`int`, *optional*): The height in pixels of the generated image.
- `width` (`int`, *optional*): The width in pixels of the generated image.
- `image_latents` (`list`, *optional*): Normalized latents of each condition image. Can be generated from vae_encoder step.
- `latents` (`Tensor`): Pre-generated noisy latents for image generation.
- `num_inference_steps` (`int`): The number of denoising steps.
- `sigmas` (`list`, *optional*): Custom sigmas for the denoising process.
- `use_kv_cache` (`bool`, *optional*, defaults to `True`): Cache the text and condition-image keys and values after the first step. Valid because `causal_condition` modulates those tokens from `t = 0`, making their activations step-independent. Toggling it does not reproduce the same image bit-for-bit in reduced precision.
- `attention_kwargs` (`dict`, *optional*): Additional kwargs for attention processors.
- `**denoiser_input_fields` (`None`, *optional*): conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
- `output_type` (`str`, *optional*, defaults to `pil`): Output format: 'pil', 'np', 'pt'.

**Outputs:**

- `images` (`list`): Generated images.