7주차 1교시: 이미지 변형

# @title 준비 B · 제공 함수 정의와 기준 결과 보기
"""The same Pillow renderer is embedded in the notebook and used for lesson images."""

from pathlib import Path
import math

from PIL import Image, ImageDraw, ImageFont, ImageOps


STYLES = {
    "echo": {
        "background": (20, 40, 44, 255), "ink": (245, 232, 202),
        "sizes": (760, 560, 390), "positions": ((40, 100), (260, 300), (480, 490)),
        "title": "AFTER HOURS", "subtitle": "01 / A QUIET REPEAT",
    },
    "archive": {
        "background": (236, 223, 195, 255), "ink": (48, 49, 42),
        "sizes": (590, 440, 300), "positions": ((70, 130), (420, 330), (170, 610)),
        "title": "STILL HERE", "subtitle": "02 / NOTES FROM A SUMMER",
    },
    "pulse": {
        "background": (177, 54, 36, 255), "ink": (250, 235, 204),
        "sizes": (640, 460, 330), "positions": ((-80, 30), (490, 240), (180, 590)),
        "title": "OFF BEAT", "subtitle": "03 / TURN IT UP",
    },
}


def load_source(path):
    """Honor phone orientation; leave the file untouched; bound working resolution."""
    with Image.open(path) as opened:
        image = ImageOps.exif_transpose(opened).convert("RGBA")
    image.thumbnail((1600, 1600), Image.Resampling.LANCZOS)
    return image


def default_crop(source):
    side = max(1, int(min(source.size) * 0.9))
    left = (source.width - side) // 2
    top = (source.height - side) // 2
    return (left, top, left + side, top + side)


def validate_crop(source, crop_box):
    assert isinstance(crop_box, (tuple, list)) and len(crop_box) == 4, "crop_box는 (왼쪽, 위, 오른쪽, 아래) 네 값입니다."
    assert all(type(value) is int for value in crop_box), "자르기 좌표는 정수로 적으세요."
    left, top, right, bottom = crop_box
    assert 0 <= left < right <= source.width and 0 <= top < bottom <= source.height, "자르기 좌표를 출력된 작업본 크기 안에서 정하세요."


def make_layer(source, crop_box, target_size, angle, alpha):
    validate_crop(source, crop_box)
    layer = source.copy().crop(crop_box)
    layer = layer.resize(target_size, Image.Resampling.LANCZOS)
    # Multiply existing alpha: transparent source pixels must stay transparent.
    layer.putalpha(layer.getchannel("A").point(lambda value: round(value * alpha / 255)))
    return layer.rotate(angle, expand=True, resample=Image.Resampling.BICUBIC, fillcolor=(0, 0, 0, 0))


def make_cover(source, crop_box, style="echo", angle=12, alpha=160, shift=0, reverse=False):
    validate_crop(source, crop_box)
    assert style in STYLES, "style은 echo, archive, pulse 중 하나입니다."
    assert isinstance(angle, (int, float)) and math.isfinite(angle) and -30 <= angle <= 30, "angle은 -30~30 사이입니다."
    assert type(alpha) is int and 0 <= alpha <= 255, "alpha는 0~255 정수입니다."
    assert type(shift) is int and -100 <= shift <= 100, "shift는 -100~100 정수입니다."
    spec = STYLES[style]
    canvas = Image.new("RGBA", (1000, 1000), spec["background"])
    layers = []
    for index, (size, position) in enumerate(zip(spec["sizes"], spec["positions"])):
        layer = make_layer(source, crop_box, (size, size), angle * (index - 1), alpha)
        layers.append((layer, (position[0] + shift * index, position[1])))
    if reverse:
        layers.reverse()
    for layer, position in layers:
        canvas.alpha_composite(layer, dest=position)
    # A supplied title strip. Typography is not a required coding task this week.
    draw = ImageDraw.Draw(canvas)
    draw.rectangle((0, 850, 1000, 1000), fill=spec["background"])
    draw.line((42, 866, 958, 866), fill=spec["ink"], width=2)
    draw.text((42, 882), spec["title"], fill=spec["ink"], font=ImageFont.load_default(size=66))
    draw.text((44, 964), spec["subtitle"], fill=spec["ink"], font=ImageFont.load_default(size=16))
    return canvas


def comparison_sheet(images, labels=None, preserve_scale=False):
    labels = labels or [str(index + 1) for index in range(len(images))]
    assert len(images) == len(labels) and len(images) > 0
    columns = min(3, len(images))
    rows = (len(images) + columns - 1) // columns
    sheet = Image.new("RGB", (columns * 340, rows * 375), (244, 240, 230))
    draw = ImageDraw.Draw(sheet)
    reference_size = max(max(image.size) for image in images)
    for index, (image, label) in enumerate(zip(images, labels)):
        x, y = index % columns * 340, index // columns * 375
        scale = 320 / (reference_size if preserve_scale else max(image.size))
        preview = image.convert("RGBA").resize(
            (max(1, round(image.width * scale)), max(1, round(image.height * scale))),
            Image.Resampling.LANCZOS,
        )
        position = (x + 10 + (320 - preview.width) // 2, y + 10 + (320 - preview.height) // 2)
        sheet.paste(preview, position, preview.getchannel("A"))
        draw.text((x + 10, y + 340), label, fill=(35, 43, 40), font=ImageFont.load_default(size=18))
    return sheet


from IPython.display import display

# 위의 함수 정의를 실행한 다음, 원본을 읽어 기준 결과를 만듭니다.
PROVIDED_PATH = "week07_provided_source.jpg"
demo_source = load_source(PROVIDED_PATH)
demo_crop = default_crop(demo_source)
demo_covers = [make_cover(demo_source, demo_crop, style=name) for name in STYLES]
display(demo_covers[0].resize((500, 500)))
print("제공 함수 준비 완료: make_cover()")
print("기준 결과: echo. 같은 사진이 서로 다른 크기와 각도로 놓인 부분을 찾으세요.")