server/text_generation_server/models/custom_modeling/gemma3/processing_gemma3.py

# coding=utf-8
# Copyright 2025 Google Inc. HuggingFace Inc. team. All rights reserved.
#
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import re
from typing import List, Optional, Union

from transformers.feature_extraction_utils import BatchFeature
from transformers.image_utils import ImageInput
from transformers.processing_utils import (
    ImagesKwargs,
    ProcessingKwargs,
    ProcessorMixin,
    Unpack,
)
from transformers.tokenization_utils_base import PreTokenizedInput, TextInput
from transformers.utils import to_py_obj
from text_generation_server.models.custom_modeling.gemma3.image_processing_gemma3 import (
    Gemma3ImageProcessor,
)

from transformers.image_utils import PILImageResampling

from .utils import make_nested_list_of_images


class Gemma3ImagesKwargs(ImagesKwargs):
    do_pan_and_scan: Optional[bool]
    pan_and_scan_min_crop_size: Optional[int]
    pan_and_scan_max_num_crops: Optional[int]
    pan_and_scan_min_ratio_to_activate: Optional[float]
    do_convert_rgb: Optional[bool]


class Gemma3ProcessorKwargs(ProcessingKwargs, total=False):
    _defaults = {
        "text_kwargs": {
            "padding": False,
        },
        "images_kwargs": {
            "do_pan_and_scan": False,
            "pan_and_scan_min_crop_size": 256,
            "pan_and_scan_max_num_crops": 4,
            "pan_and_scan_min_ratio_to_activate": 1.2,
        },
    }


class Gemma3Processor(ProcessorMixin):
    attributes = ["image_processor", "tokenizer"]
    valid_kwargs = ["chat_template"]
    # # image_processor_class = "Gemma3ImageProcessor"
    image_processor_class = "AutoProcessor"
    tokenizer_class = "AutoTokenizer"

    def __init__(
        self,
        image_processor,
        tokenizer,
        chat_template=None,
        num_mm_soft_tokens_per_image: int = 256,
        **kwargs,
    ):
        num_mm_soft_tokens_per_image = 256
        chat_template = None

        image_processor = Gemma3ImageProcessor(
            image_mean=(127.5,) * 3,
            image_std=(127.5,) * 3,
            size={"height": 896, "width": 896},
            do_rescale=False,
            resample=PILImageResampling.BILINEAR,
        )

        self.image_token_id = tokenizer.image_token_id
        image_tokens_expanded = "".join(
            [tokenizer.image_token] * num_mm_soft_tokens_per_image
        )
        self.full_image_sequence = (
            f"\n\n{tokenizer.boi_token}{image_tokens_expanded}{tokenizer.eoi_token}\n\n"
        )

        self.image_processor = image_processor
        self.tokenizer = tokenizer
        self.chat_template = chat_template

        # super().__init__(
        #     image_processor=image_processor,
        #     tokenizer=tokenizer,
        #     chat_template=chat_template,
        #     **kwargs,
        # )

    def __call__(
        self,
        images: ImageInput = None,
        text: Union[
            TextInput, PreTokenizedInput, List[TextInput], List[PreTokenizedInput]
        ] = None,
        videos=None,
        audio=None,
        **kwargs: Unpack[Gemma3ProcessorKwargs],
    ) -> BatchFeature:
        if text is None and images is None:
            raise ValueError("Provide at least one of `text` or `images`.")

        output_kwargs = self._merge_kwargs(
            Gemma3ProcessorKwargs,
            tokenizer_init_kwargs=self.tokenizer.init_kwargs,
            **kwargs,
        )

        if isinstance(text, str):
            text = [text]
        elif not isinstance(text, list) and not isinstance(text[0], str):
            raise ValueError(
                "Invalid input text. Please provide a string, or a list of strings"
            )

        image_inputs = {}
        if images is not None:
            batched_images = make_nested_list_of_images(images)
            image_inputs = self.image_processor(
                batched_images, **output_kwargs["images_kwargs"]
            )

            # Create empty text to be replaced with placeholders
            if not text:
                text = [
                    " ".join(["<image>"] * len(images)) for images in batched_images
                ]

            if len(batched_images) != len(text):
                raise ValueError(
                    f"Received inconsistently sized batches of images ({len(batched_images)}) and text ({len(text)})."
                )

            # Replace image tokens by the full expanded sequence
            batch_num_crops = to_py_obj(image_inputs.pop("num_crops"))
            for prompt, images, num_crops in zip(text, batched_images, batch_num_crops):
                image_indexes = [m.start() for m in re.finditer("<image>", prompt)]

                if len(images) != len(image_indexes):
                    raise ValueError(
                        f"Prompt contained {len(image_indexes)} image tokens but received {len(images)} images."
                    )

                # Insert additional image tokens for Pan-and-Scan crops
                for num, idx in reversed(list(zip(num_crops, image_indexes))):
                    if num:
                        formatted_image_text = (
                            "Here is the original image <image> and here are some crops to help you see better "
                            + " ".join(["<image>"] * num)
                        )
                        prompt = (
                            prompt[:idx]
                            + formatted_image_text
                            + prompt[idx + len("<image>") :]
                        )

            # Expand placeholder image tokens to the full image token sequence
            text = [
                prompt.replace("<image>", self.full_image_sequence) for prompt in text
            ]

        text_input = self.tokenizer(text=text, **output_kwargs["text_kwargs"])
        return BatchFeature(data={**text_input, **image_inputs})

    # Copied from transformers.models.clip.processing_clip.CLIPProcessor.batch_decode with CLIP->Gemma
    def batch_decode(self, *args, **kwargs):
        """
        This method forwards all its arguments to GemmaTokenizerFast's [`~PreTrainedTokenizer.batch_decode`]. Please
        refer to the docstring of this method for more information.
        """
        return self.tokenizer.batch_decode(*args, **kwargs)

    # Copied from transformers.models.clip.processing_clip.CLIPProcessor.decode with CLIP->Gemma
    def decode(self, *args, **kwargs):
        """
        This method forwards all its arguments to GemmaTokenizerFast's [`~PreTrainedTokenizer.decode`]. Please refer to
        the docstring of this method for more information.
        """
        return self.tokenizer.decode(*args, **kwargs)

    @property
    # Copied from transformers.models.clip.processing_clip.CLIPProcessor.model_input_names with CLIP->PaliGemma
    def model_input_names(self):
        tokenizer_input_names = self.tokenizer.model_input_names
        image_processor_input_names = self.image_processor.model_input_names
        return list(dict.fromkeys(tokenizer_input_names + image_processor_input_names))


__all__ = ["Gemma3Processor"]