Here are the Code examples of this chapter. These pages will be updated over time (sectioning, adding pictures, captions, and possibly further examples). I will synchronize the content with GitHub. Finally, the chapter pages and Code examples will be moved to a dedicated website TikZ.org.
Small example
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\node (A) {A};
\node[right= 4 cm of A] (B) {B};
\draw (A) edge node [fill=white] {1} (B);
\end{tikzpicture}
\end{document}
Node with style
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\node [font = \sffamily\bfseries, text=white, shape = circle, ball color = blue] (A) {A};
\end{tikzpicture}
\end{document}
Small graph
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{vertex/.style = {font = \sffamily\bfseries, text = white,
shape = circle, ball color = blue}}
\tikzset{bridge/.style = {thick, double = yellow,
double distance = 1pt}}
\tikzset{number/.style = {font = \sffamily\bfseries, text = white,
draw, fill = red}}
\begin{document}
\begin{tikzpicture}
\node[vertex] (A) {A};
\node[vertex, right = 4 cm of A] (B) {B};
\draw (A) edge[bridge] node [number] {1} (B);
\end{tikzpicture}
\end{document}
Konigsberg Bridges
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{
vertex/.style = {font = \sffamily\bfseries, text = white,
shape = circle, ball color = blue},
bridge/.style = {thick, double = yellow,
double distance = 1pt},
number/.style = {font = \sffamily\bfseries, text = white,
draw, fill = red}}
\begin{document}
\begin{tikzpicture}
\node[vertex] (A) {A};
\node[vertex, right = 4 cm of A] (B) {B};
\draw (A) edge [bridge] node [number] {1} (B);
\node[vertex, below = 2cm of A] (C) {C};
\node[vertex, above = 2cm of A] (D) {D};
\tikzset{bridge/.append style = {bend right}}
\draw (C) edge [bridge] node [number] {2} (B)
(B) edge [bridge] node [number] {3} (D)
(C) edge [bridge] node [number] {4} (A)
(A) edge [bridge] node [number] {5} (C)
(A) edge [bridge] node [number] {6} (D)
(D) edge [bridge] node [number] {7} (A);
\end{tikzpicture}
\end{document}
Inheriting styles
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{
mytext/.style = {font=\sffamily\bfseries, text=white},
vertex/.style = {mytext, shape = circle,
ball color = blue},
number/.style = {mytext, draw, fill = red}}
\tikzset{
bridge/.style = {thick, double = yellow,
double distance = 1pt}}
\begin{document}
\begin{tikzpicture}
\node[vertex] (A) {A};
\node[vertex, right = 4 cm of A] (B) {B};
\draw (A) edge [bridge] node [number] {1} (B);
\node[vertex, below = 2cm of A] (C) {C};
\node[vertex, above = 2cm of A] (D) {D};
\tikzset{bridge/.append style = {bend right}}
\draw (C) edge [bridge] node [number] {2} (B)
(B) edge [bridge] node [number] {3} (D)
(C) edge [bridge] node [number] {4} (A)
(A) edge [bridge] node [number] {5} (C)
(A) edge [bridge] node [number] {6} (D)
(D) edge [bridge] node [number] {7} (A);
\end{tikzpicture}
\end{document}
Highlight vertex and label
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{
mytext/.style = {font=\sffamily\bfseries, text=white},
vertex/.style = {mytext, shape = circle,
ball color = blue},
number/.style = {mytext, draw, fill = red}}
\tikzset{
bridge/.style = {thick, double = yellow,
double distance = 1pt}}
\tikzset{highlight/.style = {draw=yellow, very thick, densely dotted},
highlight vertex/.style = {vertex, highlight},
highlight number/.style = {number, highlight}}
\begin{document}
\begin{tikzpicture}
\node[highlight vertex] (A) {A};
\node[vertex, right = 4 cm of A] (B) {B};
\draw (A) edge [bridge] node [highlight number] {1} (B);
\node[vertex, below = 2cm of A] (C) {C};
\node[vertex, above = 2cm of A] (D) {D};
\tikzset{bridge/.append style = {bend right}}
\draw (C) edge [bridge] node [number] {2} (B)
(B) edge [bridge] node [number] {3} (D)
(C) edge [bridge] node [number] {4} (A)
(A) edge [bridge] node [number] {5} (C)
(A) edge [bridge] node [number] {6} (D)
(D) edge [bridge] node [number] {7} (A);
\end{tikzpicture}
\end{document}
One parameter
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{vertex/.style = {font = \sffamily\bfseries, text = white,
shape = circle, ball color = #1}}
\tikzset{bridge/.style = {thick, double = yellow,
double distance = 1pt}}
\tikzset{number/.style = {font = \sffamily\bfseries, text = white,
draw, fill = red}}
\begin{document}
\begin{tikzpicture}
\node[vertex=blue] (A) {A};
\node[vertex=red, right = 4 cm of A] (B) {B};
\draw (A) edge[bridge] node [number] {1} (B);
\end{tikzpicture}
\end{document}
One parameter with default value
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzset{vertex/.style = {font = \sffamily\bfseries, text = white,
shape = circle, ball color = #1},
vertex/.default = blue}
\tikzset{bridge/.style = {thick, double = yellow,
double distance = 1pt}}
\tikzset{number/.style = {font = \sffamily\bfseries, text = white,
draw, fill = red}}
\begin{document}
\begin{tikzpicture}
\node[vertex] (A) {A};
\node[vertex=red, right = 4 cm of A] (B) {B};
\draw (A) edge[bridge] node [number] {1} (B);
\end{tikzpicture}
\end{document}
Smiley pics
\documentclass[tikz,border=10pt]{standalone}
\tikzset{smiley/.pic={
\draw[shading=ball, ball color=yellow] (0,0)
circle [radius=2];
\draw[shading=ball, ball color=black] (-0.5,0.5,0)
ellipse [x radius=0.2, y radius=0.4];
\draw[shading=ball, ball color=black] (0.5,0.5,0)
ellipse [x radius=0.2, y radius=0.4];
\draw[very thick] (-1,-1) arc [start angle=185,
end angle=355, x radius=1, y radius=0.5];}}
\begin{document}
\begin{tikzpicture}
\draw
(0,0) pic{smiley}
(2,2) pic [scale=0.5, rotate=-30] {smiley}
(-2,1.5) pic [scale=0.3, rotate= 30] {smiley}
(-1.6,2) pic [scale=0.15, rotate=-20] {smiley}
(0,2) pic [scale=0.2, rotate=-10] {smiley};
\end{tikzpicture}
\end{document}