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# -*- coding: utf-8 -*-
import base64
import io
import os
from typing import List, Tuple, TypedDict
from django.conf import settings
from PIL import Image, ImageDraw, ImageFont
from PIL.ImageFont import FreeTypeFont
class TextSplitter:
"""将文本按照指定宽度进行拆分"""
def __init__(self, font: FreeTypeFont, max_width: float):
self.font = font
self.max_width = max_width
def split_word(self, word: str):
"""
将单词按照最大宽度进行拆分
"""
if self.font.getlength(word) <= self.max_width:
return [word]
parts = []
current_part = ""
for char in word:
current_part += char
if self.font.getlength(current_part) > self.max_width:
parts.append(current_part[:-1])
current_part = char
parts.append(current_part)
return parts
def split_text(self, text: str) -> List[str]:
"""
按照最大宽度对文本进行拆分，优先将单词完整地放在一行，如果单词太长再考虑从中间切开
"""
words = text.split(" ")
lines = []
current_line = ""
for word in words:
if not current_line:
current_line = word
elif self.font.getlength(f"{current_line} {word}") <= self.max_width:
current_line += " " + word
else:
lines.append(current_line)
current_line = word
# 避免行过长
if self.font.getlength(current_line) > self.max_width:
parts = self.split_word(current_line)
lines.extend(parts[:-1])
# 保留最后一个切片用于下次拼接
current_line = parts[-1]
if current_line:
lines.append(current_line)
return lines
class Params(TypedDict):
plaintext: str
background_color: Tuple[int, int, int, int]
image_width: int
image_height: int
padding: int
font_size: int
font_color: Tuple[int, int, int, int]
rotation_angle: float
def generate(params: Params) -> str:
"""生成明水印"""
# 获取配置信息
plaintext = params["plaintext"]
background_color = params["background_color"]
image_width = params["image_width"]
image_height = params["image_height"]
padding = params["padding"]
font_size = params["font_size"]
font_color = params["font_color"]
rotation_angle = params["rotation_angle"]
font = ImageFont.truetype(os.path.join(settings.BASE_DIR, "static/font/SourceHanSerifCN-Regular.ttf"), font_size)
# 生成水印
text_width, text_height = font.getsize(plaintext)
blank = Image.new("RGBA", (image_width, image_height), background_color)
draw = ImageDraw.Draw(blank)
# 拆分文本为多行
multiline_text = TextSplitter(font, blank.width).split_text(plaintext)
# 计算每行文本的高度和总高度
total_height = text_height * len(multiline_text)
# 逐行绘制文本
for i, line in enumerate(multiline_text):
line_width, _ = font.getsize(line)
x = (blank.width - line_width) / 2
y = (blank.height - total_height) / 2 + i * text_height
draw.text((x, y), line, font=font, fill=font_color)
# 裁剪出文字
box = [
0,
total_height / 2,
blank.width,
blank.height / 2 + total_height / 2,
]
text_im = blank.crop(box)
# 旋转后裁剪大小
text_rotate = text_im.rotate(rotation_angle, expand=True)
text_rotate = text_rotate.resize((image_width, image_height), Image.ANTIALIAS)
# 填充边距
img = Image.new("RGBA", (image_width + padding, image_height + padding), background_color)
paste_box = (int(padding / 2), int(padding / 2))
img.paste(text_rotate, paste_box)
img = img.resize((image_width, image_height), Image.ANTIALIAS)
# 将图片转换为base64字符串
buffer = io.BytesIO()
img.save(buffer, format="PNG")
return base64.b64encode(buffer.getvalue()).decode("utf8")
def test() -> str:
return generate(
Params(
plaintext="Raja abcdefghijklmnopqrstuvwxyz This is a long text 这是一段很长的文本 这是一段很长的文本",
background_color=(255, 255, 255, 0),
image_width=260,
image_height=165,
padding=40,
font_size=16,
font_color=(0, 0, 0, 50),
rotation_angle=30,
)
)
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