| """Business logic services.""" |
|
|
| import io |
| import logging |
|
|
| from PIL import Image |
|
|
| logger = logging.getLogger(__name__) |
|
|
|
|
| def remove_exif_orientation(image: Image.Image, *, exif_orientation_tag: int) -> Image.Image: |
| try: |
| exif = image.getexif() |
| if not exif: |
| return image |
|
|
| orientation = exif.get(exif_orientation_tag) |
| if not orientation or orientation == 1: |
| return image |
|
|
| if image.mode == "RGBA": |
| new_image = Image.new("RGBA", image.size) |
| else: |
| new_image = Image.new("RGB", image.size) |
| new_image.paste(image) |
| return new_image |
| except Exception as e: |
| logger.warning(f"移除 EXIF 方向标签失败: {e}") |
| return image |
|
|
|
|
| def clean_image(image_data: bytes, *, img_format: str, exif_orientation_tag: int) -> bytes: |
| img: Image.Image = Image.open(io.BytesIO(image_data)) |
|
|
| |
| fmt = (img_format or "jpeg").upper() |
| if fmt == "JPEG": |
| try: |
| exif = img.getexif() |
| orientation = exif.get(exif_orientation_tag, 1) if exif else 1 |
| except Exception: |
| orientation = 1 |
| |
| if orientation in (1, None) and img.mode == "RGB": |
| return image_data |
|
|
| img = remove_exif_orientation(img, exif_orientation_tag=exif_orientation_tag) |
|
|
| output = io.BytesIO() |
|
|
| if fmt == "JPEG": |
| if img.mode in ("RGBA", "P"): |
| background: Image.Image = Image.new("RGB", img.size, (255, 255, 255)) |
| if img.mode == "RGBA": |
| background.paste(img, mask=img.split()[3]) |
| else: |
| background.paste(img) |
| img = background |
| elif img.mode != "RGB": |
| img = img.convert("RGB") |
| img.save(output, format="JPEG", quality=85, optimize=True) |
| else: |
| img.save(output, format=fmt) |
|
|
| return output.getvalue() |
|
|
|
|
| def resize_to_paper_size( |
| image_bytes: bytes, |
| *, |
| paper_size: str, |
| paper_sizes: dict[str, tuple[int, int]], |
| dpi: int = 300, |
| ) -> bytes: |
| img: Image.Image = Image.open(io.BytesIO(image_bytes)) |
| width, height = img.size |
|
|
| target_width_mm, target_height_mm = paper_sizes[paper_size] |
| target_width = int(target_width_mm * dpi / 25.4) |
| target_height = int(target_height_mm * dpi / 25.4) |
|
|
| target_ratio = target_width / target_height |
| img_ratio = width / height |
|
|
| if img_ratio > target_ratio: |
| new_width = target_width |
| new_height = int(target_width / img_ratio) |
| else: |
| new_height = target_height |
| new_width = int(target_height * img_ratio) |
|
|
| img = img.resize((new_width, new_height), Image.Resampling.LANCZOS) |
|
|
| background = Image.new("RGB", (target_width, target_height), (255, 255, 255)) |
| x = (target_width - new_width) // 2 |
| y = (target_height - new_height) // 2 |
| background.paste(img, (x, y)) |
|
|
| output = io.BytesIO() |
| background.save(output, format="JPEG", quality=85) |
| return output.getvalue() |
|
|
|
|
| def rotate_image_for_output(image_data: bytes, *, rotation: int, img_format: str) -> bytes: |
| if rotation not in (0, 90, 180, 270): |
| rotation = 0 |
|
|
| img: Image.Image = Image.open(io.BytesIO(image_data)) |
| pillow_angle = (360 - rotation) % 360 |
| if pillow_angle != 0: |
| img = img.rotate(pillow_angle, expand=True) |
|
|
| output = io.BytesIO() |
| fmt = (img_format or "jpeg").upper() |
|
|
| if fmt == "JPEG": |
| if img.mode in ("RGBA", "P"): |
| background: Image.Image = Image.new("RGB", img.size, (255, 255, 255)) |
| if img.mode == "RGBA": |
| background.paste(img, mask=img.split()[3]) |
| else: |
| background.paste(img) |
| img = background |
| elif img.mode != "RGB": |
| img = img.convert("RGB") |
| img.save(output, format="JPEG", quality=85, optimize=True) |
| else: |
| img.save(output, format=fmt) |
|
|
| return output.getvalue() |
|
|
