[P&D/CG] 究進青龍！

最近迷上了 P&D 這遊戲，玩了 12x 天，現在已是 218 rank，可惜還沒有可以橫掃降臨的強隊（這類隊伍多需要數千元的課金額 ...）。

以下是究進了的（水暗）青龍！因為是龍的關係，特地學習有關龍的畫法：

呀呀呀，以下才是主角！

把它們合併並作一些微調：

彩圖用的線稿正在處理中！

[Beamer] 有用的小技巧

快要 defense，presentation 決定採用 beamer 形式裝作 power point (原因嘛，簡單方便快捷！)。

技巧 1. 一般人對 beamer 感到最厭煩的就是每一個 \frame{} 裏都要加上 \frametitle{}，其作用有點類似文章的 section。漏掉的話會整欄空掉，蠻奇怪的。以下一段 code 能夠在接着的 frame 中不斷承繼上一個 frame 的 title (直至令立 title 為止)：

 \makeatletter  
 \def\beamer@checkframetitle{%  
 \begingroup  
  \edef\temp{%  
   \endgroup  
   \noexpand\frametitle  
   [\unexpanded\expandafter{\beamer@savedshortframetitle}]%  
   {\unexpanded\expandafter{\beamer@savedframetitle}}%  
  }  
 \temp  
 \@ifnextchar\bgroup\beamer@inlineframetitle{}}  
 \long\def\beamer@@frametitle[#1]#2{%  
  \beamer@ifempty{#2}{}{%  
   \gdef\insertframetitle{{#2\ifnum\beamer@autobreakcount>0\relax{}\space\usebeamertemplate*{frametitle  
 continuation}\fi}}%  
  \gdef\beamer@frametitle{#2}%  
  \gdef\beamer@shortframetitle{#1}%  
  \global\let\beamer@savedshortframetitle\beamer@shortframetitle  
   \global\let\beamer@savedframetitle\beamer@frametitle  
 }%  
 }  
  \global\let\beamer@savedshortframetitle\@empty  
   \global\let\beamer@savedframetitle\@empty  
 \makeatother  

技巧 2. 若數式以 align/align* environment 進行等號對齊，用家會發現在 "\\" 後加上 \pause 會出現錯誤。beamer 這先天的缺點有以下的 solution：

 \makeatletter  
 \def\pdftex@driver{pdftex.def}  
 \ifx\Gin@driver\pdftex@driver  
  \def\pgfsys@color@unstacked#1{%  
   \pdfliteral{\csname\string\color@#1\endcsname}%  
  }  
 \fi  
 \makeatother  

[Tikz] Draw contours with midway arrow

The code is as follows: In the preamble, paste (with the package "tikz" loaded of course!):

 \usetikzlibrary{decorations.pathreplacing,decorations.markings}  
 \tikzset{  
  % style to apply some styles to each segment of a path  
  on each segment/.style={  
   decorate,  
   decoration={  
    show path construction,  
    moveto code={},  
    lineto code={  
     \path [#1]  
     (\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);  
    },  
    curveto code={  
     \path [#1] (\tikzinputsegmentfirst)  
     .. controls  
     (\tikzinputsegmentsupporta) and (\tikzinputsegmentsupportb)  
     ..  
     (\tikzinputsegmentlast);  
    },  
    closepath code={  
     \path [#1]  
     (\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);  
    },  
   },  
  },  
  % style to add an arrow in the middle of a path  
  mid arrow/.style={postaction={decorate,decoration={  
     markings,  
     mark=at position .5 with {\arrow[#1]{stealth}}  
    }}},  
 }  

As an exmaple, see:

 \begin{tikzpicture}[scale=2]  
 \clip (0.6,3.75) rectangle (3.85,0.85);  
 \draw[thick] (0,0) ellipse (3 and 3);  
 \draw[postaction={on each segment={mid arrow}}] (60:2) arc (60:30:2) -- (30:2.8) arc(30:60:2.8)--cycle;  
 \draw[postaction={on each segment={mid arrow}}] (30:4.2)arc (30:60:4.2) --(60:3.2)arc (60:30:3.2)--cycle;  
 \node at (1.745,1.795) {$L_1(r)$};  
 \node at (0.9,2.15) {$L_2(r)$};  
 \node at (1.225,1.2) {$L_3(r)$};  
 \node at (2.275,1) {$L_4(r)$};  
 \node at (2.5,2.425) {$T_1(r)$};  
 \node at (3.45,1.65) {$T_2(r)$};  
 \node at (3.225,3.125) {$T_3(r)$};  
 \node at (1.575,3.325) {$T_4(r)$};  
 \end{tikzpicture}