dzungpham / font-diffusion-weights

Model Card for FontDiffuser

Model Details

Model Type

• Architecture : Diffusion-based Font Generation Model
• Framework : PyTorch + Hugging Face Diffusers
• Scheduler : DPM-Solver++ (configurable: dpmsolver++ / dpmsolver)
• Guidance : Classifier-free guidance
• Base Model : FontDiffuser with Content and Style Encoders

Model Components

1. UNet : Main diffusion model for image generation
2. Content Encoder : Extracts character structure information
3. Style Encoder : Extracts font style features
4. DDPM/DPM Scheduler : Noise scheduling for diffusion process

Training Configuration

• Resolution : 96×96 pixels
• Batch Size : 4-8 (configurable)
• Inference Steps : 15 (default, configurable)
• Guidance Scale : 7.5 (default, configurable)
• Precision : FP32/FP16 (optional)
• Device : CUDA/GPU recommended

Model Usage

Installation

pip install diffusers torch torchvision safetensors
pip install lpips scikit-image pytorch-fid  # Optional: for evaluation

Basic Generation

from sample_batch import (
    FontManager, 
    batch_generate_images,
    load_fontdiffuser_pipeline
)
from argparse import Namespace

# Initialize font manager
font_manager = FontManager("path/to/font.ttf")

# Load pipeline
args = Namespace(
    ckpt_dir="path/to/checkpoints",
    device="cuda",
    num_inference_steps=15,
    guidance_scale=7.5,
    batch_size=4,
    # ... other args
)
pipe = load_fontdiffuser_pipeline(args)

# Generate images
characters = ['A', 'B', 'C', '中', '国']
style_paths = ['style1.png', 'style2.png']

results = batch_generate_images(
    pipe, characters, style_paths,
    output_dir="output",
    args=args,
    evaluator=evaluator,
    font_manager=font_manager
)

Batch Generation with Checkpointing

python sample_batch.py \
  --characters "characters.txt" \
  --start_line 1 \
  --end_line 100 \
  --style_images "styles/" \
  --ttf_path "fonts/myfont.ttf" \
  --ckpt_dir "checkpoints/" \
  --output_dir "my_dataset/train_original" \
  --batch_size 4 \
  --num_inference_steps 15 \
  --guidance_scale 7.5 \
  --save_interval 10 \
  --device cuda

Resume from Checkpoint

python sample_batch.py \
  --characters "characters.txt" \
  --style_images "styles/" \
  --ttf_path "fonts/myfont.ttf" \
  --ckpt_dir "checkpoints/" \
  --output_dir "my_dataset/train_original" \
  --resume_from "my_dataset/train_original/results_checkpoint.json"

Model Performance

Supported Tasks

• ✅ Single-character font generation
• ✅ Multi-character batch generation
• ✅ Multi-font support
• ✅ Multi-style transfer
• ✅ Index-based tracking for large-scale generation
• ✅ Checkpoint and resume support

Output Format

output_dir/
├── ContentImage/              # Single set of content (character) images
│   ├── char0.png
│   ├── char1.png
│   └── ...
├── TargetImage/               # Generated font images organized by style
│   ├── style0/
│   │   ├── style0+char0.png
│   │   ├── style0+char1.png
│   │   └── ...
│   ├── style1/
│   │   └── ...
│   └── ...
├── results.json               # Comprehensive generation metadata
├── results_checkpoint.json    # Intermediate checkpoint (if save_interval > 0)
└── results_interrupted.json   # Emergency checkpoint (if interrupted)

Results Metadata Structure

{
  "generations": [
    {
      "character": "A",
      "char_index": 0,
      "style": "style0",
      "style_index": 0,
      "font": "Arial",
      "style_path": "path/to/style0.png",
      "output_path": "TargetImage/style0/style0+char0.png"
    }
  ],
  "metrics": {
    "lpips": {"mean": 0.25, "std": 0.08, "min": 0.1, "max": 0.5},
    "ssim": {"mean": 0.82, "std": 0.05, "min": 0.7, "max": 0.95},
    "fid": {"mean": 15.3, "std": 2.1},
    "inference_times": [
      {
        "style": "style0",
        "style_index": 0,
        "font": "Arial",
        "total_time": 2.45,
        "num_images": 100,
        "time_per_image": 0.0245
      }
    ]
  },
  "fonts": ["Arial", "Times New Roman"],
  "characters": ["A", "B", "C"],
  "styles": ["style0", "style1"],
  "total_chars": 3,
  "total_styles": 2,
  "total_possible_pairs": 6
}

Evaluation Metrics

Supported Metrics

• LPIPS : Learned perceptual image patch similarity (lower is better)
• SSIM : Structural similarity index (higher is better)
• FID : Fréchet Inception Distance (lower is better)
• Inference Time : Per-image generation time

Generate with Evaluation

python sample_batch.py \
  --characters "characters.txt" \
  --style_images "styles/" \
  --ttf_path "fonts/myfont.ttf" \
  --ckpt_dir "checkpoints/" \
  --output_dir "my_dataset/train_original" \
  --evaluate \
  --ground_truth_dir "ground_truth/" \
  --compute_fid

Dataset

Dataset Source

• Name : font-diffusion-generated-data
• Link : https://huggingface.co/datasets/dzungpham/font-diffusion-generated-data
• Format : ContentImage + TargetImage per style
• Supports : Multi-font, multi-character, multi-style generation

Dataset Structure

FontDiffusion Dataset/
├── train_original/
│   ├── ContentImage/          # Character structure images
│   ├── TargetImage/           # Style-specific font renderings
│   └── results.json
├── val_original/
└── test_original/

Training & Fine-tuning

Fine-tuning from Checkpoint

python my_train.py \
  --ckpt_dir "checkpoints/" \
  --data_dir "my_dataset/train_original" \
  --output_dir "finetuned_ckpt/" \
  --num_epochs 5 \
  --learning_rate 1e-4 \
  --batch_size 4

Convert & Upload Fine-tuned Models

python finetune_and_upload.py \
  --ckpt_dir "finetuned_ckpt/" \
  --hf_token "hf_xxxxx" \
  --hf_repo_id "username/font-diffusion-finetuned" \
  --num_epochs 5

Technical Features

Optimizations

• ✅ Batch Processing : Process multiple characters per style
• ✅ Memory Efficiency : Attention slicing (optional)
• ✅ FP16 Support : Reduced precision for faster inference
• ✅ Torch Compile : Optional model compilation
• ✅ Channels Last Format : Memory-optimized tensor layout
• ✅ XFormers Support : Fast attention implementation

Robustness

• ✅ Checkpoint & Resume : Resume from interruptions
• ✅ Index-based Tracking : Handle large character sets (100K+)
• ✅ Multi-font Support : Process characters across multiple fonts
• ✅ Error Recovery : Graceful handling of missing fonts
• ✅ Automatic Indexing : Consistent char_index and style_index

Monitoring

• ✅ Weights & Biases Integration : Real-time tracking
• ✅ Progress Bars : Detailed generation progress
• ✅ Checkpoint Saving : Periodic intermediate saves
• ✅ Quality Metrics : LPIPS, SSIM, FID computation

Known Limitations

• Requires CUDA-capable GPU for practical generation speeds
• Characters must exist in at least one loaded font
• Style images should be normalized (96×96 or resizable)
• Very large character sets (>100K) may require memory optimization
• FID computation requires representative ground truth dataset

Citation

@article{fontdiffuser2023,
  title={FontDiffuser: One-Shot Font Generation via Denoising Diffusion with Multi-Scale Content Aggregation and Style Contrastive Learning},
  author={Zhenhua Yang, Dezhi Peng, Yuxin Kong, Yuyi Zhang, Cong Yao, Lianwen Jin},
  year={2023}
}

License

This model is licensed under the Apache License 2.0. See LICENSE file for details.

Contact & Support

For issues, questions, or contributions:

• GitHub: [FontDiffusion Repository]
• Hugging Face: [Model Card]
• Dataset: https://huggingface.co/datasets/dzungpham/font-diffusion-generated-data

---