"""Render a top view from the exported binary STL meshes using Pillow."""
from pathlib import Path
import struct
from PIL import Image, ImageDraw, ImageFont

ROOT = Path(__file__).resolve().parent.parent
OUT = ROOT / 'models' / 'print_shop_joined_eight'
image = Image.new('RGB',(1200,1120),'#f5f7fa')
draw = ImageDraw.Draw(image)
font_path='C:/Windows/Fonts/msyh.ttc'
font=ImageFont.truetype(font_path,32)
small=ImageFont.truetype(font_path,23)
tiny=ImageFont.truetype(font_path,19)
draw.text((60,35),'打印店交付：每组 8 个垫片',font=font,fill='#172d4d')
draw.text((60,90),'支架单独一个文件；以下两组分别作为拼件提交',font=small,fill='#53677e')

def draw_mesh(filename,left,top,color):
    data=(OUT/filename).read_bytes()
    count=struct.unpack_from('<I',data,80)[0]
    if len(data)!=84+50*count:raise RuntimeError('Expected binary STL')
    scale=10
    # Bounding box x=-5.543..29.543, y=-6..54; flip Y for screen.
    def xy(x,y):return (left+(x+5.543277)*scale,top+(54-y)*scale)
    for i in range(count):
        t=struct.unpack_from('<12fH',data,84+i*50)
        pts=[xy(t[3],t[4]),xy(t[6],t[7]),xy(t[9],t[10])]
        draw.polygon(pts,fill=color)

draw.text((150,155),'0.5 mm 垫片 × 8',font=font,fill='#996115')
draw.text((680,155),'1.0 mm 垫片 × 8',font=font,fill='#087c76')
draw_mesh('垫片0.5mm_8个拼件.stl',165,230,'#dc9b40')
draw_mesh('垫片1.0mm_8个拼件.stl',695,230,'#339b91')
draw.text((60,900),'两组均为一体拼件，每组 7 根连接杆，截面 1.8 × 1.8 mm。',font=small,fill='#304764')
draw.text((60,945),'颜色仅用于区分厚度；打印后从垫片外缘剪除连接杆并修平。',font=small,fill='#304764')
draw.text((60,990),'垫片与连接杆的实际结合面受垫片厚度限制，生产前请商家确认。',font=tiny,fill='#8a4b14')
draw.text((60,1035),'图为 STL 顶视示意，实际切片及成品以打印商评估为准。',font=tiny,fill='#53677e')
image.save(OUT/'拼件预览.png')