LaTeX - Pgf/Tikz

Table of Contents

Introduction

Pgf/tikz is an excellent LaTeX package to plot high quality graphs. This post just summaries its basic usages.

Installation

Pgf/Tikz is a built-in package in the texlive. As long as texlive is ready, pgf/tikz is out-of-the-box.

Basic usage

Setting

\usepackage{tikz}
...
\tikz ...
\begin{tikzpicture}
...
\end{tikzpicture}

Style

Create a new style

\tikzstyle{newstylename}=[option1=value1, option2=value2, ...]

For example, following styles can be defined for nodes in a flowchart. 

\tikzstyle{startstop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm, text centered, text width=5cm, draw=black, fill=red!30]
\tikzstyle{io} = [trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=3cm, minimum height=1cm, text centered, text width=5cm, draw=black, fill=blue!30]
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, text width=5cm, draw=black, fill=orange!30]
\tikzstyle{decision} = [diamond, minimum width=3cm, minimum height=1cm, text centered, text width=5cm, draw=black, fill=green!30]
\tikzstyle{arrow} = [thick, ->, >=stealth]

Modify an existing style

\tikzstyle{existingstylename}+=[option1=value1, option2=value2, ...]

Coordinate

  • (x, y)
  • (angle: radius)

List

% step length = 1
{a, ..., b}
...
% step length = d
{a, a + d, ..., b}

Arrow

  • -
  • ->
  • <-
  • <->
  • ->>

Draw

Line

\draw (x1, y1) -- (x2, y2) -- (x3, y3) -- cycle

Curve

\draw (x1, y1) .. controls (x2, y2) and (x3, y3) .. (x4, y4);
\draw (x1, y1) .. controls (x2, y2) .. (x3, y3);

Grid

\draw [step=s] (x1, y1) grid (x2, y2);
\draw [xstep=x_s, ystep=y_s] (x1, y1) grid (x2, y2);

Arc

\draw (x1, y1) arc (start_angle: end_angle: radius);

Rectangle

\draw (x1, y1) rectangle (x2, y2);
\fill [color] (x1, y1) rectangle (x2, y2);
\filldraw [fill=color1, draw=color2] (x1, y1) rectangle (x2, y2);
\shade [inner/top/left color=color1, outer/bottom/right color=color2] (x1, y1) rectangle (x2, y2);
\shadedraw [inner/top/left color=color1, outer/bottom/right color=color2, draw=color3] (x1, y1) rectangle (x2, y2);
\clip (x1, y1) rectangle (x2, y2);

Circle

\draw (x1, y1) circle (radius);
\fill [color] (x1, y1) circle (radius);
\filldraw [fill=color1, draw=color2] (x1, y1) circle (radius);
\shade [inner/top/left color=color1, outer/bottom/right color=color2] (x1, y1) circle (radius);
\shadedraw [inner/top/left color=color1, outer/bottom/right color=color2, draw=color3] (x1, y1) circle (radius);
\clip (x1, y1) circle (radius);

Ellipse

\draw (x1, y1) ellipse (x_radius and y_radius);
\fill [color] (x1, y1) ellipse (x_radius and y_radius);
\filldraw [fill=color1, draw=color2] (x1, y1) ellipse (x_radius and y_radius);
\shade [inner/top/left color=color1, outer/bottom/right color=color2] (x1, y1) ellipse (x_radius and y_radius);
\shadedraw [inner/top/left color=color1, outer/bottom/right color=color2, draw=color3] (x1, y1) ellipse (x_radius and y_radius);
\clip (x1, y1) ellipse (x_radius and y_radius);

Node

(x0, y0) node [anchor=north/south/east/west, shape=circle/rectangle/ellipse, draw=color1, fill=color2, label=angle:node_label_angle] (node_name) {node_label};
...
\node at (x0, y0) (node_name) {node_label};
Connecting nodes with
  • Lines
\draw [arrow] (node_name_A) to (node_name_B);
\draw (node_name_A) edge [arrow, color] (node_name_B);
  • Curves
\draw [arrow] (node_name_A) to [bend left/right=30] (node_name_B);
\draw [arrow] (node_name_A) to [in=30, out=60] (node_name_B);
\draw (node_name_A) edge [arrow, color, in=30, out=60] (node_name_B);
\draw (node_name_A) edge [arrow, color, bend left/right=30] (node_name_B);

Refer to nodes outside current picture

\tikzstyle{every picture}+=[remember picture]
...
\tikz[overlay]
\begin{tikzpicture}[overlay]
...
\end{tikzpicture}

Mix tikz command with LaTeX

\tikz [baseline] ...

Libraries

Besides the basic tikz package, there are some libraries for dedicated purpose.

tikzcd for commutative diagrams

  • Load the package 

    % Method-1
\usepackage{tikz}
\usetikzlibrary{cd}

% Method-2
\usepackage{tikz-cd}
  • Usage

    • Environment for a commutative diagram 

      \begin{tikzcd}[OPTIONS]
    CONTENTS
\end{tikzcd}
      • The CONTENTS are structured in a matrix style, e.g., with & and \\ to separate columns and rows respectively.
      • Everything inside {tikz} is typeset in math mode.

    • Arrow In fact, an arrow object can follow either its starting or ending node (matrix element). But in my opinion, it is intuitionally natural to create an arrow object following its starting node. 

      \arrow[OPTIONS]
\ar[OPTIONS]

      where OPTIONS is a comma-separated list of options to specify an arrow, e.g.,

      • direction, consisting of a string of characters.
        • u for up
        • d for down
        • l for left
        • r for right
      • label, quoted string on an arrow.
        • An arrow can have an arbitrary number of labels, with common separated.
        • If a label string consists of commas, then the label string should be enclosed in a pair of curly braces.
        • Optionally label-specific options can follow a target label (without comma separated), e.g.,
          • A color option, e.g., red.
          • A location option, e.g., near start, near end.
          • An apostrophe (') flips the label to the opposite side of the arrow.
          • A multiplicity of options should be separated with commas and enclosed in a pair of curly braces.
      • color
      • line type, e.g., dashed, dotted, etc.
      • arrow type, e.g., leftarrow, rightarrow, leftrightarrow, Leftarrow, Rightarrow, Leftrightarrow, etc.
      • Fine tuning, e.g., shift left=1ex, shift right=1ex.
      • crossing over for 3-dimensional diagrams.
      • marking places a preceding label over the arrow.
      • description places a preceding label over the arrow with background filled.

    • Global option 

      \tikzcdset{OPTIONS}

      The options in OPTIONS are usually defined in every diagram, every cell, every arrow, every label, etc. and reinitialized when the command above is called.

      • every diagram 

        row sep=normal,
column sep=normal,
/tikz/baseline=0pt

      • every matrix 

        /tikz/inner sep=0pt

      • every cell 

        /tikz/shape=asymmetrical rectangle,
/tikz/inner xsep=1ex,
/tikz/inner ysep=0.85ex

      • every arrow 

        /tikz/draw,
/tikz/line width=rule_thickness,
rightarrow

      • every label 

        /tikz/auto,
/tikz/font=something,
/tikz/inner sep=0.5ex