Tikz 绘制 flowchart 流程图

效果（Result）：

代码如下（The code is shown as follows）：

documentclass{article}
usepackage{amsthm,amsmath,amssymb}
usepackage{amsfonts}
usepackage{tikz}
usetikzlibrary{positioning, shapes.geometric}
usetikzlibrary{calc}

% Define the basic shape of flow chart
	ikzstyle{startstop} = [rectangle, rounded corners, minimum width = 2cm, minimum height=1cm,text centered, draw = black, fill = red!30]
	ikzstyle{io} = [trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=2cm, minimum height=1cm, text centered, draw=black, fill = blue!25]
	ikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill = yellow!35]
	ikzstyle{decision} = [diamond, aspect = 3, text centered, minimum width = 2.5cm, draw=black, fill = green!45]
% arrow shape
	ikzstyle{arrow} = [->,>=stealth]

usepackage[active,pdftex,tightpage]{preview}
PreviewEnvironment{tikzpicture}
setlength{PreviewBorder}{0.5bp}

begin{document}

begin{figure}[htbp]
centering
begin{tikzpicture}[node distance = 1.2cm]
  % Define flowchart  shape
  
ode (start) [startstop] {Start};
  
ode (in1) [io, below of = start, yshift=-0.2cm, minimum width=1cm] {Input};
  
ode (dec1) [decision, below of=in1, yshift=-0.2cm] {cycle 1};
  
ode (pro1) [process, below of=dec1,yshift=-0.2cm] {process 1};
  
ode (dec2) [decision, below of=pro1, yshift=-0.2cm] {cycle 2};
  
ode (pro2) [process, below of=dec2,yshift=-0.2cm] {Process 2};
  
ode (pro3) [process, below of=pro2,yshift=-0.2cm] {Process 3};
  
ode (pro4) [process, below of=pro3,yshift=-0.2cm] {Process 4};
  
ode (in2)  [io, below of=pro4, yshift=-0.2cm] {Output};
  
ode (stop) [startstop, below of=in2,node distance = 1.6cm] {End};
  % connect
  draw[arrow] (start)  -- (in1);
  draw[arrow] (in1) -- (dec1);
  draw[arrow] (dec1.west)-- node[anchor=south] {N} ($(dec1.west) - (1.3,0)$) |- ($(stop.north)!.3!(in2.south)$) -- (stop);
  draw[arrow] (dec1) -- node[anchor=west] {Y} (pro1);
  draw[arrow] (pro1) -- (dec2);
  draw[arrow] (dec2.east) -- node[anchor=south] {N} ($(dec2.east) + (1.3,0)$) |- ($(in1.south)!.5!(dec1.north)$);
  draw[arrow] (dec2) -- node[anchor=west] {Y} (pro2);
  draw[arrow] (pro2) -- (pro3);
  draw[arrow] (pro3) -- (pro4);
  draw[arrow] (pro4) -- (in2);
  draw[arrow] (in2.south)  -- ($(in2.south)-(0,0.2)$) -- ($(in2.south) - (2.2,0.2)$) |- ($(pro1.south)!.5!(dec2.north)$);
end{tikzpicture}
caption{The flowchart}label{fig:flowchart}
end{figure}

end{document}

若要输出的 pdf 不含白边，则在导言区加入如下代码：

usepackage[active,pdftex,tightpage]{preview}
PreviewEnvironment{tikzpicture}
%set the size of white edge
setlength{PreviewBorder}{0.5bp}

作者：李金磊

邮箱：lijinlei0907@163.com

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