我想在 MetaPost 中计算轮廓集合的并集。我知道buildcycle宏（与cutbefore和结合使用cutafter）。但是，该宏不是很有用，因为我事先不知道要连接的形状，因此很难预测如何“构建”循环。
使问题复杂化的是，路径的某些部分非常细，这会导致舍入问题。
我知道这一点相关问题但理想情况下我需要一个 MetaPost 解决方案。
以下是一个可能的例子。路径实际上是使用 MetaPost 计算的，并集也是使用 MetaPost 计算的。不过，这样做的方式并不理想。我希望有一个更强大的解决方案。
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endfig;
end;
FWIW：如果你想知道的话，我正在制作一种书法字体，希望在 2015 年的 TUG 日历上展示。字体基于我的笔迹。H以上是粗略的近似值:-)
答案1
这是基于我去年评论中的想法的答案；虽然它没有直接回答你关于路径联合的一般问题，但它确实表明 MP 可以接近直接绘制你的角色。
请注意penpos注意做允许你在笔划移动时改变笔的倾斜度，事实上这就是它的重点。下面是起草你的H字符。我添加的唯一非 的plain东西是制作一个 版本，penstroke它执行filldraw而不是fill。
prologues := 3;
outputtemplate := "%j%c.eps";
def tt_penstroke text t =
forsuffixes e = l,r: path_.e:=t; endfor
filldraw path_.l -- reverse path_.r -- cycle enddef;
path path_.l,path_.r;
beginfig(1);
u = cm;
w = 3u;
h = 7u;
y1 = h; y2 = y4 = 0;
x1 = x4 = .9 w; x2 = 0;
x3 = .7w; y3 = .52h;
pair s, t; s = dir 264; t = dir 220;
penpos1(5mm,30);
penpos2(5mm,45);
penpos3(5mm,30);
penpos4(5mm,45);
pickup pensquare rotated 45 scaled 2;
tt_penstroke z1e{t} ..{s}z2e;
tt_penstroke z2e{-s} .. z3e{right} .. {s}z4e;
endfig;
end.