212 lines
7.6 KiB
Python
212 lines
7.6 KiB
Python
"""
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3D 立体验证码生成器
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生成具有 3D 透视/阴影效果的验证码：
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- 使用仿射变换模拟 3D 透视
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- 添加阴影效果 (偏移的深色副本)
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- 字符有深度感和倾斜
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- 渐变背景增强立体感
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- 标签: 纯字符内容
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"""
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import math
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import random
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from PIL import Image, ImageDraw, ImageFilter, ImageFont
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from config import GENERATE_CONFIG, THREED_CHARS
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from generators.base import BaseCaptchaGenerator
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# 字体 (粗体效果更好渲染 3D)
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_FONT_PATHS = [
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"/usr/share/fonts/TTF/DejaVuSans-Bold.ttf",
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"/usr/share/fonts/TTF/DejaVuSerif-Bold.ttf",
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"/usr/share/fonts/liberation/LiberationSans-Bold.ttf",
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"/usr/share/fonts/liberation/LiberationSerif-Bold.ttf",
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"/usr/share/fonts/gnu-free/FreeSansBold.otf",
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]
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# 前景色 — 鲜艳、对比度高
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_FRONT_COLORS = [
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(220, 50, 50), # 红
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(50, 100, 220), # 蓝
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(30, 160, 30), # 绿
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(200, 150, 0), # 金
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(180, 50, 180), # 紫
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(0, 160, 160), # 青
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(220, 100, 0), # 橙
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]
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class ThreeDCaptchaGenerator(BaseCaptchaGenerator):
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"""3D 立体验证码生成器。"""
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def __init__(self, seed: int | None = None):
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from config import RANDOM_SEED
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super().__init__(seed=seed if seed is not None else RANDOM_SEED)
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self.cfg = GENERATE_CONFIG["3d"]
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self.chars = THREED_CHARS
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self.width, self.height = self.cfg["image_size"]
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# 预加载可用字体
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self._fonts: list[str] = []
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for p in _FONT_PATHS:
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try:
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ImageFont.truetype(p, 20)
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self._fonts.append(p)
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except OSError:
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continue
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if not self._fonts:
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raise RuntimeError("未找到任何可用字体，无法生成验证码")
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# ----------------------------------------------------------
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# 公共接口
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# ----------------------------------------------------------
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def generate(self, text: str | None = None) -> tuple[Image.Image, str]:
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rng = self.rng
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# 1. 随机文本
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if text is None:
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length = rng.randint(*self.cfg["char_count_range"])
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text = "".join(rng.choices(self.chars, k=length))
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# 2. 渐变背景 (增强立体感)
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img = self._gradient_background(rng)
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# 3. 逐字符绘制 (阴影 + 透视 + 前景)
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self._draw_3d_text(img, text, rng)
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# 4. 干扰线 (较粗、有深度感)
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self._draw_depth_lines(img, rng)
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# 5. 轻微高斯模糊
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img = img.filter(ImageFilter.GaussianBlur(radius=0.7))
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return img, text
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# ----------------------------------------------------------
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# 私有方法
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# ----------------------------------------------------------
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def _gradient_background(self, rng: random.Random) -> Image.Image:
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"""生成从上到下的浅色渐变背景。"""
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img = Image.new("RGB", (self.width, self.height))
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draw = ImageDraw.Draw(img)
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# 随机两个浅色
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c1 = tuple(rng.randint(200, 240) for _ in range(3))
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c2 = tuple(rng.randint(180, 220) for _ in range(3))
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for y in range(self.height):
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ratio = y / max(self.height - 1, 1)
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r = int(c1[0] + (c2[0] - c1[0]) * ratio)
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g = int(c1[1] + (c2[1] - c1[1]) * ratio)
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b = int(c1[2] + (c2[2] - c1[2]) * ratio)
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draw.line([(0, y), (self.width, y)], fill=(r, g, b))
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return img
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def _draw_3d_text(self, img: Image.Image, text: str, rng: random.Random) -> None:
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"""逐字符绘制 3D 效果: 阴影层 + 透视变换 + 前景层。"""
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n = len(text)
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slot_w = self.width // n
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font_size = int(min(slot_w * 0.8, self.height * 0.65))
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font_size = max(font_size, 16)
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shadow_dx, shadow_dy = self.cfg["shadow_offset"]
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for i, ch in enumerate(text):
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font_path = rng.choice(self._fonts)
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font = ImageFont.truetype(font_path, font_size)
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front_color = rng.choice(_FRONT_COLORS)
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# 阴影色: 对应前景色的暗化版本
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shadow_color = tuple(max(0, c - 80) for c in front_color)
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# 渲染单字符
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bbox = font.getbbox(ch)
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cw = bbox[2] - bbox[0] + 8
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ch_h = bbox[3] - bbox[1] + 8
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pad = max(shadow_dx, shadow_dy) + 4 # 额外空间给阴影
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canvas_w = cw + pad * 2
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canvas_h = ch_h + pad * 2
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# --- 阴影层 ---
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shadow_img = Image.new("RGBA", (canvas_w, canvas_h), (0, 0, 0, 0))
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ImageDraw.Draw(shadow_img).text(
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(-bbox[0] + pad + shadow_dx, -bbox[1] + pad + shadow_dy),
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ch, fill=shadow_color + (180,), font=font
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)
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# --- 前景层 ---
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front_img = Image.new("RGBA", (canvas_w, canvas_h), (0, 0, 0, 0))
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ImageDraw.Draw(front_img).text(
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(-bbox[0] + pad, -bbox[1] + pad),
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ch, fill=front_color + (255,), font=font
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)
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# 合并: 先阴影后前景
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char_img = Image.new("RGBA", (canvas_w, canvas_h), (0, 0, 0, 0))
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char_img = Image.alpha_composite(char_img, shadow_img)
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char_img = Image.alpha_composite(char_img, front_img)
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# 透视变换 (仿射)
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char_img = self._perspective_transform(char_img, rng)
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# 随机旋转
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angle = rng.randint(-20, 20)
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char_img = char_img.rotate(angle, resample=Image.BICUBIC, expand=True)
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# 粘贴到画布
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x = slot_w * i + (slot_w - char_img.width) // 2
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y = (self.height - char_img.height) // 2 + rng.randint(-4, 4)
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x = max(0, min(x, self.width - char_img.width))
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y = max(0, min(y, self.height - char_img.height))
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img.paste(char_img, (x, y), char_img)
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def _perspective_transform(self, img: Image.Image, rng: random.Random) -> Image.Image:
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"""对单个字符图片施加仿射变换模拟 3D 透视。"""
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w, h = img.size
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intensity = self.cfg["perspective_intensity"]
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# 随机 shear / scale 参数
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shear_x = rng.uniform(-intensity, intensity)
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shear_y = rng.uniform(-intensity * 0.5, intensity * 0.5)
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scale_x = rng.uniform(1.0 - intensity * 0.3, 1.0 + intensity * 0.3)
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scale_y = rng.uniform(1.0 - intensity * 0.3, 1.0 + intensity * 0.3)
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# 仿射变换矩阵 (a, b, c, d, e, f) -> (x', y') = (a*x+b*y+c, d*x+e*y+f)
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# Pillow transform 需要逆变换系数
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a = scale_x
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b = shear_x
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d = shear_y
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e = scale_y
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# 计算偏移让中心不变
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c = (1 - a) * w / 2 - b * h / 2
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f = -d * w / 2 + (1 - e) * h / 2
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return img.transform(
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(w, h), Image.AFFINE,
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(a, b, c, d, e, f),
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resample=Image.BICUBIC
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)
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def _draw_depth_lines(self, img: Image.Image, rng: random.Random) -> None:
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"""绘制有深度感的干扰线 (较粗、带阴影)。"""
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draw = ImageDraw.Draw(img)
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num = rng.randint(2, 4)
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for _ in range(num):
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x1, y1 = rng.randint(0, self.width), rng.randint(0, self.height)
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x2, y2 = rng.randint(0, self.width), rng.randint(0, self.height)
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# 阴影线
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shadow_color = tuple(rng.randint(80, 130) for _ in range(3))
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dx, dy = self.cfg["shadow_offset"]
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draw.line([(x1 + dx, y1 + dy), (x2 + dx, y2 + dy)],
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fill=shadow_color, width=rng.randint(2, 3))
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# 前景线
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color = tuple(rng.randint(120, 200) for _ in range(3))
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draw.line([(x1, y1), (x2, y2)], fill=color, width=rng.randint(1, 2))
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