src/attention_utils.py

import torch
import numpy as np
from typing import Tuple, List
from cv2 import putText, getTextSize, FONT_HERSHEY_SIMPLEX
# import matplotlib.pyplot as plt
from PIL import Image

from src.prompt_to_prompt_controllers import AttentionStore

def aggregate_attention(attention_store: AttentionStore, res: int, from_where: List[str], is_cross: bool, select: int, prompts):
    out = []
    attention_maps = attention_store.get_average_attention()
    num_pixels = res ** 2
    for location in from_where:
        for item in attention_maps[f"{location}_{'cross' if is_cross else 'self'}"]:
            if item.shape[1] == num_pixels:
                cross_maps = item.reshape(len(prompts), -1, res, res, item.shape[-1])[select]
                out.append(cross_maps)
    out = torch.cat(out, dim=0)
    out = out.sum(0) / out.shape[0]
    return out.cpu()


def show_cross_attention(attention_store: AttentionStore, res: int, from_where: List[str], prompts, tokenizer, select: int = 0):
    tokens = tokenizer.encode(prompts[select])
    decoder = tokenizer.decode
    attention_maps = aggregate_attention(attention_store, res, from_where, True, select, prompts)
    images = []
    for i in range(len(tokens)):
        image = attention_maps[:, :, i]
        image = 255 * image / image.max()
        image = image.unsqueeze(-1).expand(*image.shape, 3)
        image = image.numpy().astype(np.uint8)
        image = np.array(Image.fromarray(image).resize((256, 256)))
        image = text_under_image(image, decoder(int(tokens[i])))
        images.append(image)
    view_images(np.stack(images, axis=0))


def show_self_attention_comp(attention_store: AttentionStore, res: int, from_where: List[str],
                             max_com=10, select: int = 0):
    attention_maps = aggregate_attention(attention_store, res, from_where, False, select).numpy().reshape(
        (res ** 2, res ** 2))
    u, s, vh = np.linalg.svd(attention_maps - np.mean(attention_maps, axis=1, keepdims=True))
    images = []
    for i in range(max_com):
        image = vh[i].reshape(res, res)
        image = image - image.min()
        image = 255 * image / image.max()
        image = np.repeat(np.expand_dims(image, axis=2), 3, axis=2).astype(np.uint8)
        image = Image.fromarray(image).resize((256, 256))
        image = np.array(image)
        images.append(image)
    view_images(np.concatenate(images, axis=1))


def view_images(images, num_rows=1, offset_ratio=0.02):
    if type(images) is list:
        num_empty = len(images) % num_rows
    elif images.ndim == 4:
        num_empty = images.shape[0] % num_rows
    else:
        images = [images]
        num_empty = 0

    empty_images = np.ones(images[0].shape, dtype=np.uint8) * 255
    images = [image.astype(np.uint8) for image in images] + [empty_images] * num_empty
    num_items = len(images)

    h, w, c = images[0].shape
    offset = int(h * offset_ratio)
    num_cols = num_items // num_rows
    image_ = np.ones((h * num_rows + offset * (num_rows - 1),
                      w * num_cols + offset * (num_cols - 1), 3), dtype=np.uint8) * 255
    for i in range(num_rows):
        for j in range(num_cols):
            image_[i * (h + offset): i * (h + offset) + h:, j * (w + offset): j * (w + offset) + w] = images[
                i * num_cols + j]

    pil_img = Image.fromarray(image_)
    display(pil_img)


def text_under_image(image: np.ndarray, text: str, text_color: Tuple[int, int, int] = (0, 0, 0)):
    h, w, c = image.shape
    offset = int(h * .2)
    img = np.ones((h + offset, w, c), dtype=np.uint8) * 255
    font = FONT_HERSHEY_SIMPLEX
    img[:h] = image
    textsize = getTextSize(text, font, 1, 2)[0]
    text_x, text_y = (w - textsize[0]) // 2, h + offset - textsize[1] // 2
    putText(img, text, (text_x, text_y ), font, 1, text_color, 2)
    return img


def display(image):
    global display_index
    plt.imshow(image)
    plt.show()