常用案例

图片模式转换（RGB to CMYK）

from PIL import Image, ImageCms
from typing import Literal
from os import path

ImgMode = Literal["CMYK", "RGB"]


def img_mode_transform(
    img_path: str,
    img_profile: str,
    output_profile: str,
    output_mode: ImgMode,
    output_file: str = None,
) -> str:
    """
    @Description 修改图片的颜色模式：`RGB`=>`CMYK`、`CMYK`=>`RGB`

    - param img_path       :{str}     文件绝对路径，仅支持`.jpg`、`.tif`文件
    - param img_profile    :{str}     文件的颜色文件：`icc`、`icm`等颜色文件
    - param output_profile :{str}     要输出的颜色文件：`icc`、`icm`等颜色文件
    - param output_mode    :{ImgMode} `"CMYK"`"=>"`"RGB"`
    - param output_file    :{str}     {description}

    @returns `{ str }` 返回输出文件的路径，失败返回空字符
    ```py
    input_file = "./img/mimi_rgb.jpg"
    input_file_icc = "./img/sRGB IEC61966-21.icc"
    output_icc = "./img/Japan Color 2001 Coated.icc"

    img_mode_transform(input_file, input_file_icc, output_icc, "CMYK")
    ```
    """

    try:
        img = Image.open(img_path)

        new_img = ImageCms.profileToProfile(
            im=img,
            inputProfile=img_profile,
            outputProfile=output_profile,
            outputMode=output_mode,
            inPlace=False,
        )

        if not output_file:
            name, ext = path.splitext(img_path)
            output_file = f"{name}_{output_mode}{ext}"

        new_img.save(output_file)

    except Exception as e:
        print("img_mode_transform failed: ", e)

四点仿射

PIL

# 矩阵计算函数
#
# @param      pb    背景仿射
# @param      pa    产品四点投射点数据
#
# @return     The perspective transform.
#
def getPerspectiveTransform(pb, pa):
    matrix = []
    for p1, p2 in zip(pa, pb):
        matrix.append([p1[0], p1[1], 1, 0, 0, 0, -p2[0] * p1[0], -p2[0] * p1[1]])
        matrix.append([0, 0, 0, p1[0], p1[1], 1, -p2[1] * p1[0], -p2[1] * p1[1]])
    A = np.matrix(matrix, dtype=np.float)
    B = np.array(pb).reshape(8)
    res = np.dot(np.linalg.inv(A.T * A) * A.T, B)
    return np.array(res).reshape(8)

##
# @brief      { 修改产品透视,并和底图合并 }
##
# @param      tar   目标文件, 绝对路径, string
# @param      xy    [(x,y),(x,y),(x,y),(x,y)] -左上角开始 顺时针 二维数组 内部可以是 turple
# @param      bg    The background
##
# @return     { description_of_the_return_value }
##
def perspectiveByPIL(tar, bg, fg=None, xy=None, output=None, saveName=None):
    # 实例化透视对象
    # try:
    nxy = []
    saveName = saveName or os.path.join(output, os.path.basename(bg))

    img = Image.open(tar).convert('RGBA')
    bg_img = Image.open(bg).convert('RGBA')

    # 获取宽高
    img_width = bg_img.width
    img_height = bg_img.height

    # 将产品设置成场景相同尺寸
    img = img.resize((bg_img.width, bg_img.height), Image.ANTIALIAS)

    # 左上角开始 顺时针
    if not xy:
        left_top = [95, 134.796875]  # 左上
        right_top = [95, 134.796875]  # 右上
        right_down = [195, 209.28125]  # 右下
        left_down = [195, 209.28125]  # 左下

        # 偏移模式
        # nxy = [left_top,
        # (img_width-right_top[0],right_top[1]),
        # (img_width-right_down[0],img_height-right_down[1]),
        # (left_down[0],img_height-left_down[1])]

        # 坐标模式
        nxy = [left_top, right_top, right_down, left_down]

    else:
        # nxy = [xy[0],
        # (img_width-xy[1][0],xy[1][1]),
        # (img_width-xy[2][0],img_height-xy[2][1]),
        # (xy[3][0],img_height-xy[3][1])]

        nxy = [xy[0], xy[1], xy[2], xy[3]]

    # 原图的范围
    scope = [(0, 0), (img_width, 0), (img_width, img_height), (0, img_height)]

    # 仿射点矩阵计算
    perspective = getPerspectiveTransform(scope, nxy)

    # 仿射生成图片
    fg_img = img.transform((img_width, img_height), Image.PERSPECTIVE, perspective, Image.BICUBIC, fill=1, fillcolor=(200, 210, 0, 0))

    # 合并图层[通过遮罩]
    new_img = Image.composite(fg_img, bg_img, fg_img)

    if fg:
        # 读取前景
        front_img =Image.open(fg).convert('RGBA')

        # 将产品设置成场景相同尺寸
        if front_img.width != bg_img.width:
            front_img = front_img.resize((bg_img.width, bg_img.height))

        # 将前景进行合成
        new_img = Image.composite(front_img, new_img, front_img)

    save_img = new_img.convert('RGB')

    save_img.save(saveName)

    return 'success'

# 使用
if (__name__ == "__main__"):
    if len(sys.argv) < 2:
        # 测试环境
        config={
            "factory_name": 'yibu',
            "product_url": '/factorys/5f9c264cfac73e3d0cad5a18/5f9c2d22a16792339484ca61/004853a8be5310e06d53139e70551864.webp',
            "front_url": '/factorys/yibu/scene/02/h/front.webp',
            "background_url": '/factorys/yibu/scene/02/h/bg.webp',
            "left_down": [277, 739],
            "left_top": [279, 262],
            "right_down": [1041, 768],
            "right_top": [1042, 128],
            "username": 'admin',
            "product_path": r'D:\\CPS\\MyProject\\honegqi_online\\server\\app\\public\\factorys\\5f9c264cfac73e3d0cad5a18\\5f9c2d22a16792339484ca61\\004853a8be5310e06d53139e70551864.webp',
            "background_path": r'D:\\CPS\\MyProject\\honegqi_online\\server\\app\\public\\factorys\\yibu\\scene\\02\\h\\bg.webp',
            "output_path": r'D:\\CPS\\MyProject\\honegqi_online\\server\\app\\public\\factorys\\yibu\\scene\\02\\h',
            "front_path": r'D:\\CPS\\MyProject\\honegqi_online\\server\\app\\public\\factorys\\yibu\\scene\\02\\h\\front.webp',
            "saveName": r'D:\\CPS\\MyProject\\honegqi_online\\server\\app\\public\\factorys\\yibu\\scene\\02\\h\\0d5ba2724e80e6e38b35188793b81849.jpg'
        }
        tar = config['product_path']
        bg = config['background_path']
        output = config['output_path']
        fg = config['front_path'] or None

        xy = [
            config['left_top'],
            config['right_top'],
            config['right_down'],
            config['left_down'],
        ]
        saveName = config['saveName'] or None
        print(perspectiveByPIL(tar, bg, xy=xy, output=output, saveName=saveName, fg=fg))

    else:
        # 生成环境
        # print(len(sys.argv))
        config = json.loads(sys.argv[1].replace('@', '"'))
        tar = config['product_path']
        bg = config['background_path']
        output = config['output_path']

        if 'front_path' in config:
            fg = config['front_path']
        else:
            fg=None

        xy = [
            config['left_top'],
            config['right_top'],
            config['right_down'],
            config['left_down'],
        ]

        if 'saveName' in config:
            saveName = config['saveName'] or None
        else:
            saveName = None

        print(perspectiveByPIL(tar, bg, xy=xy, output=output, saveName=saveName, fg=fg))
        # print(config)

指定DPI导出A4图片

以下函数只能转换A4，

from os import path

import fitz
from PIL import Image
import io

def export_pdf_to_paper_size(pdf_path, output_path, dpi=300, paper_size="A4"):
    # 定义A4和A3的尺寸（毫米）并转换为像素
    paper_sizes = {"A4": (210, 297), "A3": (297, 420)}
    width_mm, height_mm = paper_sizes.get(paper_size, ("A4"))

    # 毫米转英寸再乘以DPI
    target_width = int(width_mm / 25.4 * dpi)
    target_height = int(height_mm / 25.4 * dpi)

    # 打开PDF并获取页面
    doc = fitz.open(pdf_path)
    for page in doc:
        original_width = page.rect.width  # 原始宽度（点）
        original_height = page.rect.height  # 原始高度（点）

        # 计算适应目标尺寸的缩放比例
        scale_w = target_width / original_width
        scale_h = target_height / original_height
        scale = min(scale_w, scale_h)  # 保持宽高比

        # 生成缩放后的图像
        matrix = fitz.Matrix(scale, scale)
        pix = page.get_pixmap(matrix=matrix, dpi=dpi)
        # pix.save(output_path + f"page-{page.number}.jpg", "jpg", jpg_quality=70)

        img = Image.open(io.BytesIO(pix.tobytes()))

        # 创建目标尺寸画布并居中粘贴
        canvas = Image.new("RGB", (target_width, target_height), (255, 255, 255))
        x = (target_width - img.width) // 2
        y = (target_height - img.height) // 2
        canvas.paste(img, (x, y))

        # 保存结果
        canvas.info["dpi"] = (dpi, dpi)  # 写入DPI信息
        canvas.save(output_path + f"page-{page.number}.jpg", "JPEG", quality=95, dpi=(dpi, dpi))

    doc.close()


if __name__ == "__main__":
    tar = path.abspath(r"../testData/广州市番禺区金光大道工程(富怡路至亚运大道以南段)防洪评价工作大纲及报价书.pdf")

    # pdf_to_jpg(tar, ".")
    export_pdf_to_paper_size(tar, ".")

A3

def pdf_to_a3_jpg(pdf_path: str, page_num: int, output_path: str, dpi=300, page_size="A4", ext="jpg", mode="stretch"):
    """
    mode参数说明：
    - "cover": 缩放填充整个画布，自动裁剪溢出部分（默认）
    - "contain": 保持完整比例，可能留白
    - "stretch": 拉伸变形填充（不推荐）
    """
    # 定义纸张尺寸库（毫米）
    paper_sizes = {"A4": (210, 297), "A3": (297, 420), "A3-Landscape": (420, 297)}  # 新增横向尺寸支持

    # 参数校验
    if page_size not in paper_sizes:
        raise ValueError(f"Unsupported page size: {page_size}")
    if mode not in ["cover", "contain", "stretch"]:
        raise ValueError(f"Invalid mode: {mode}")

    # 获取目标尺寸（毫米转像素）
    width_mm, height_mm = paper_sizes[page_size]
    target_width = int(width_mm / 25.4 * dpi)
    target_height = int(height_mm / 25.4 * dpi)

    # 打开PDF并获取页面
    doc = fitz.open(pdf_path)
    page = doc.load_page(page_num)

    # 获取实际内容区域（自动去除白边）
    content_rect = page.rect  # 默认使用整个页面
    for annot in page.annots():
        if annot.type[0] == 8:  # 检查是否有裁剪标记
            content_rect = annot.rect
            break

    original_width = content_rect.width
    original_height = content_rect.height

    # 计算缩放比例
    if mode == "contain":
        scale = min(target_width / original_width, target_height / original_height)
    elif mode == "cover":
        scale = max(target_width / original_width, target_height / original_height)
    else:  # stretch模式
        scale_w = target_width / original_width
        scale_h = target_height / original_height

    # 生成缩放矩阵
    matrix = fitz.Matrix(scale, scale) if mode != "stretch" else fitz.Matrix(scale_w, scale_h)

    # 渲染时使用内容区域
    pix = page.get_pixmap(matrix=matrix, clip=content_rect, dpi=dpi)

    img = Image.open(io.BytesIO(pix.tobytes()))

    # 最终尺寸处理
    if mode == "stretch":
        img = img.resize((target_width, target_height))
    elif mode == "cover":
        # 二次裁剪确保精确尺寸
        img = img.crop(
            (
                (img.width - target_width) // 2,
                (img.height - target_height) // 2,
                (img.width + target_width) // 2,
                (img.height + target_height) // 2,
            )
        )

    # 直接使用渲染尺寸（不再创建空白画布）
    img.info["dpi"] = (dpi, dpi)
    img.save(output_path, quality=95, dpi=(dpi, dpi))

    doc.close()
    return output_path

从内存读取图片

# pix可以是然和实例带.tobytes()方法即可
img = Image.open(io.BytesIO(pix.tobytes()))