使用 MetaPost 繪製數學圖像

MetaPost 是一個專用的繪製數學類圖形的 latex 包
官網:
https://www.tug.org/metapost.html
user manual 下載:
https://www.tug.org/docs/metapost/mpman.pdf
以下是一個可以實現實時繪圖腳本實時預覽的網站:
http://www.tlhiv.org/mppreview/

繪製箭頭圖

我們輸入一段代碼：

drawarrow (0,45)--(0,0);
drawarrow (5,45)--(45,0)
dashed evenly withcolor blue;
drawarrow (5,-2.5)--(45,-2.5);
drawarrow (5,-5)--(45,-5);
label(btex $X$ etex, (0,50));
label(btex $Y$ etex, (0,-3.5));
label(btex $Z$ etex, (50,-3.5));

得到效果圖：

繪製函數圖像

numeric ux, uy;
120ux=1.2in; 4uy=2.4in;
draw (0,4uy)--(0,0)--(120ux,0);
pickup pencircle scaled 1pt;
draw (0,uy){right}
for ix=1 upto 8:
..(15ix*ux, uy*2/(1+cosd 15ix))
endfor;
label.bot(btex $x$ axis etex, (60ux,0));
label.lft(btex $y$ axis etex rotated 90,
(0,2uy));
label.lft(btex $\displaystyle y=\frac{2}{1+\cos x} $ etex,
(120ux, 4uy));

效果圖：

在這裏插入代碼片

畫圓

draw (0,0)..(10,0)..(0,0);

預覽

畫矩形

draw (0,0)--(10,0)--(10,10)--(0,10)--(0,0);

預覽

注意：

--繪製的是直線，..繪製的是光滑曲線

設置顏色

drawoptions(withcolor red);
draw (0,0)..(10,0)..(0,0);

設置虛線

draw (0,0)..(10,0)..(0,0) dashed(dashpattern(on 1 off 1)) withcolor red;

預覽

調節線寬

draw (0,0)..(10,0)..(0,0) dashed(dashpattern(on 1 off 1)) withcolor red withpen pencircle scaled 0.2pt;
draw (0,0)..(20,0)..(0,0) dashed(dashpattern(on 1 off 1)) withcolor blue withpen pencircle scaled 1pt;

預覽