src/backend/upscale/tiled_upscale.py

import time
import math
import logging
from PIL import Image, ImageDraw, ImageFilter
from backend.models.lcmdiffusion_setting import DiffusionTask
from context import Context
from constants import DEVICE


def generate_upscaled_image(
    config,
    input_path=None,
    strength=0.3,
    scale_factor=2.0,
    tile_overlap=16,
    upscale_settings=None,
    context: Context = None,
    output_path=None,
    image_format="PNG",
):
    if config == None or (
        input_path == None or input_path == "" and upscale_settings == None
    ):
        logging.error("Wrong arguments in tiled upscale function call!")
        return

    # Use the upscale_settings dict if provided; otherwise, build the
    # upscale_settings dict using the function arguments and default values
    if upscale_settings == None:
        upscale_settings = {
            "source_file": input_path,
            "target_file": None,
            "output_format": image_format,
            "strength": strength,
            "scale_factor": scale_factor,
            "prompt": config.lcm_diffusion_setting.prompt,
            "tile_overlap": tile_overlap,
            "tile_size": 256,
            "tiles": [],
        }
        source_image = Image.open(input_path)  # PIL image
    else:
        source_image = Image.open(upscale_settings["source_file"])

    upscale_settings["source_image"] = source_image

    if upscale_settings["target_file"]:
        result = Image.open(upscale_settings["target_file"])
    else:
        result = Image.new(
            mode="RGBA",
            size=(
                source_image.size[0] * int(upscale_settings["scale_factor"]),
                source_image.size[1] * int(upscale_settings["scale_factor"]),
            ),
            color=(0, 0, 0, 0),
        )
    upscale_settings["target_image"] = result

    # If the custom tile definition array 'tiles' is empty, proceed with the
    # default tiled upscale task by defining all the possible image tiles; note
    # that the actual tile size is 'tile_size' + 'tile_overlap' and the target
    # image width and height are no longer constrained to multiples of 256 but
    # are instead multiples of the actual tile size
    if len(upscale_settings["tiles"]) == 0:
        tile_size = upscale_settings["tile_size"]
        scale_factor = upscale_settings["scale_factor"]
        tile_overlap = upscale_settings["tile_overlap"]
        total_cols = math.ceil(
            source_image.size[0] / tile_size
        )  # Image width / tile size
        total_rows = math.ceil(
            source_image.size[1] / tile_size
        )  # Image height / tile size
        for y in range(0, total_rows):
            y_offset = tile_overlap if y > 0 else 0  # Tile mask offset
            for x in range(0, total_cols):
                x_offset = tile_overlap if x > 0 else 0  # Tile mask offset
                x1 = x * tile_size
                y1 = y * tile_size
                w = tile_size + (tile_overlap if x < total_cols - 1 else 0)
                h = tile_size + (tile_overlap if y < total_rows - 1 else 0)
                mask_box = (  # Default tile mask box definition
                    x_offset,
                    y_offset,
                    int(w * scale_factor),
                    int(h * scale_factor),
                )
                upscale_settings["tiles"].append(
                    {
                        "x": x1,
                        "y": y1,
                        "w": w,
                        "h": h,
                        "mask_box": mask_box,
                        "prompt": upscale_settings["prompt"],  # Use top level prompt if available
                        "scale_factor": scale_factor,
                    }
                )

    # Generate the output image tiles
    for i in range(0, len(upscale_settings["tiles"])):
        generate_upscaled_tile(
            config,
            i,
            upscale_settings,
            context=context,
        )

    # Save completed upscaled image
    if upscale_settings["output_format"].upper() == "JPEG":
        result_rgb = result.convert("RGB")
        result.close()
        result = result_rgb
    result.save(output_path)
    result.close()
    source_image.close()
    return


def get_current_tile(
    config,
    context,
    strength,
):
    config.lcm_diffusion_setting.strength = strength
    config.lcm_diffusion_setting.diffusion_task = DiffusionTask.image_to_image.value
    if (
        config.lcm_diffusion_setting.use_tiny_auto_encoder
        and config.lcm_diffusion_setting.use_openvino
    ):
        config.lcm_diffusion_setting.use_tiny_auto_encoder = False
    current_tile = context.generate_text_to_image(
        settings=config,
        reshape=True,
        device=DEVICE,
        save_config=False,
    )[0]
    return current_tile


# Generates a single tile from the source image as defined in the
# upscale_settings["tiles"] array with the corresponding index and pastes the
# generated tile into the target image using the corresponding mask and scale
# factor; note that scale factor for the target image and the individual tiles
# can be different, this function will adjust scale factors as needed
def generate_upscaled_tile(
    config,
    index,
    upscale_settings,
    context: Context = None,
):
    if config == None or upscale_settings == None:
        logging.error("Wrong arguments in tile creation function call!")
        return

    x = upscale_settings["tiles"][index]["x"]
    y = upscale_settings["tiles"][index]["y"]
    w = upscale_settings["tiles"][index]["w"]
    h = upscale_settings["tiles"][index]["h"]
    tile_prompt = upscale_settings["tiles"][index]["prompt"]
    scale_factor = upscale_settings["scale_factor"]
    tile_scale_factor = upscale_settings["tiles"][index]["scale_factor"]
    target_width = int(w * tile_scale_factor)
    target_height = int(h * tile_scale_factor)
    strength = upscale_settings["strength"]
    source_image = upscale_settings["source_image"]
    target_image = upscale_settings["target_image"]
    mask_image = generate_tile_mask(config, index, upscale_settings)

    config.lcm_diffusion_setting.number_of_images = 1
    config.lcm_diffusion_setting.prompt = tile_prompt
    config.lcm_diffusion_setting.image_width = target_width
    config.lcm_diffusion_setting.image_height = target_height
    config.lcm_diffusion_setting.init_image = source_image.crop((x, y, x + w, y + h))

    current_tile = None
    print(f"[SD Upscale] Generating tile {index + 1}/{len(upscale_settings['tiles'])} ")
    if tile_prompt == None or tile_prompt == "":
        config.lcm_diffusion_setting.prompt = ""
        config.lcm_diffusion_setting.negative_prompt = ""
        current_tile = get_current_tile(config, context, strength)
    else:
        # Attempt to use img2img with low denoising strength to
        # generate the tiles with the extra aid of a prompt
        # context = get_context(InterfaceType.CLI)
        current_tile = get_current_tile(config, context, strength)

    if math.isclose(scale_factor, tile_scale_factor):
        target_image.paste(
            current_tile, (int(x * scale_factor), int(y * scale_factor)), mask_image
        )
    else:
        target_image.paste(
            current_tile.resize((int(w * scale_factor), int(h * scale_factor))),
            (int(x * scale_factor), int(y * scale_factor)),
            mask_image.resize((int(w * scale_factor), int(h * scale_factor))),
        )
    mask_image.close()
    current_tile.close()
    config.lcm_diffusion_setting.init_image.close()


# Generate tile mask using the box definition in the upscale_settings["tiles"]
# array with the corresponding index; note that tile masks for the default
# tiled upscale task can be reused but that would complicate the code, so
# new tile masks are instead created for each tile
def generate_tile_mask(
    config,
    index,
    upscale_settings,
):
    scale_factor = upscale_settings["scale_factor"]
    tile_overlap = upscale_settings["tile_overlap"]
    tile_scale_factor = upscale_settings["tiles"][index]["scale_factor"]
    w = int(upscale_settings["tiles"][index]["w"] * tile_scale_factor)
    h = int(upscale_settings["tiles"][index]["h"] * tile_scale_factor)
    # The Stable Diffusion pipeline automatically adjusts the output size
    # to multiples of 8 pixels; the mask must be created with the same
    # size as the output tile
    w = w - (w % 8)
    h = h - (h % 8)
    mask_box = upscale_settings["tiles"][index]["mask_box"]
    if mask_box == None:
        # Build a default solid mask with soft/transparent edges
        mask_box = (
            tile_overlap,
            tile_overlap,
            w - tile_overlap,
            h - tile_overlap,
        )
    mask_image = Image.new(mode="RGBA", size=(w, h), color=(0, 0, 0, 0))
    mask_draw = ImageDraw.Draw(mask_image)
    mask_draw.rectangle(tuple(mask_box), fill=(0, 0, 0))
    mask_blur = mask_image.filter(ImageFilter.BoxBlur(tile_overlap - 1))
    mask_image.close()
    return mask_blur