tikz

What this skill does

# TikZ/PGF — Vector Graphics & Diagrams

**CTAN:** https://ctan.org/pkg/pgf  
**Manual:** `texdoc tikz` (~1300 pages)

## Setup

```latex
\usepackage{tikz}
% Load libraries as needed:
\usetikzlibrary{arrows.meta, calc, positioning, decorations.pathmorphing,
  patterns, shapes.geometric, shapes.misc, fit, backgrounds,
  automata, trees, mindmap, circuits.logic.US}
```

## Basic Drawing

### Minimal Example

```latex
\begin{tikzpicture}
  \draw (0,0) -- (2,0) -- (2,2) -- cycle;  % triangle
\end{tikzpicture}
```

### Path Operations

| Operation | Syntax | Example |
|-----------|--------|---------|
| Line | `--` | `(0,0) -- (1,1)` |
| Horizontal-vertical | <code>-\|</code> | `(0,0) -| (1,1)` (go right then up) |
| Vertical-horizontal | <code>\|-</code> | `(0,0) |- (1,1)` (go up then right) |
| Curve | `.. controls .. ..` | `(0,0) .. controls (0.5,1) .. (1,0)` |
| Smooth curve | `to[out=..,in=..]` | `(0,0) to[out=90,in=180] (2,1)` |
| Arc | `arc` | `(0,0) arc (0:90:1cm)` start:end:radius |
| Circle | `circle` | `(0,0) circle[radius=1]` |
| Ellipse | `ellipse` | `(0,0) ellipse[x radius=2, y radius=1]` |
| Rectangle | `rectangle` | `(0,0) rectangle (2,1)` |
| Grid | `grid` | `(0,0) grid (3,3)` |
| Parabola | `parabola` | `(0,0) parabola (2,2)` |
| Sin/Cos | `sin`/`cos` | `(0,0) sin (1,1)` |
| Plot | `plot` | `plot[domain=0:3] (\x, {\x^2})` |
| Cycle | `cycle` | close path back to start |

### Path Actions

| Command | Effect |
|---------|--------|
| `\draw` | Stroke the path |
| `\fill` | Fill the path |
| `\filldraw` | Fill and stroke |
| `\path` | Invisible path (for coordinates, nodes) |
| `\clip` | Clip subsequent drawing to path |
| `\shade` | Gradient fill |
| `\shadedraw` | Gradient fill + stroke |
| `\node` | Shorthand for `\path node` |
| `\coordinate` | Shorthand for `\path coordinate` |

### Common Draw Options

```latex
\draw[
  color=blue,            % or just: blue
  line width=1pt,        % or: thin, thick, very thick, ultra thick
  dashed,                % or: dotted, dash dot, dash dot dot
  dash pattern={on 3pt off 2pt},
  rounded corners=5pt,
  ->                     % arrow tip (see arrows section)
  opacity=0.5,
  double,
  double distance=2pt,
] (0,0) -- (2,2);
```

### Common Fill Options

```latex
\fill[
  fill=blue!20,          % 20% blue
  fill opacity=0.5,
  pattern=north lines,   % requires patterns library
  pattern color=gray,
] (0,0) rectangle (2,1);
```

## Coordinate Systems

```latex
% Cartesian (default)
(2, 3)

% Polar (angle:radius)
(45:2cm)

% Relative (shift from last point)
++(1,0)    % move reference point
+(1,0)     % don't move reference point

% Named
\coordinate (A) at (1,2);
\draw (A) -- (2,3);

% Intersection (calc library)
\usetikzlibrary{calc}
($(A)!0.5!(B)$)           % midpoint of A and B
($(A)!0.5!90:(B)$)        % midpoint rotated 90°
($(A) + (1,2)$)           % A shifted by (1,2)
($(A)!1cm!(B)$)           % 1cm from A toward B

% Perpendicular coordinates (A -| B) = (x of B, y of A)
(A |- B)                   % (x of A, y of B)

% Barycentric
(barycentric cs:A=1,B=1,C=1)  % centroid
```

## Nodes

### Basic Nodes

```latex
\node (name) at (0,0) {Text};

% Node options
\node[
  draw,                    % draw border
  fill=yellow!20,
  rectangle,               % shape (default)
  circle,
  ellipse,
  rounded corners,
  minimum width=2cm,
  minimum height=1cm,
  inner sep=5pt,           % padding
  outer sep=2pt,           % margin
  text=red,
  font=\bfseries\small,
  align=center,            % for multi-line: use \\ in text
  text width=3cm,
  anchor=north,            % positioning anchor
  rotate=45,
] (mynode) at (1,2) {Hello\\World};
```

### Node Anchors

```
          north west  north  north east
                 ┌──────────┐
            west │  center   │ east
                 └──────────┘
          south west  south  south east
```

Also: `base`, `mid`, `text`, and angle anchors like `45`, `135`.

### Nodes on Paths

```latex
\draw (0,0) -- node[above] {label} (3,0);
\draw (0,0) -- node[midway, sloped, above] {sloped text} (3,2);
\draw (0,0) -- node[pos=0.3, below] {at 30\%} (3,0);
\draw (0,0) to[out=90,in=0] node[near start, left] {A} (2,2);
```

### Common Shapes (requires libraries)

```latex
\usetikzlibrary{shapes.geometric, shapes.misc}

\node[diamond, draw] {D};
\node[star, draw, star points=5] {S};
\node[regular polygon, regular polygon sides=6, draw] {Hex};
\node[trapezium, draw] {T};
\node[cylinder, draw, shape border rotate=90] {DB};
\node[cloud, draw, cloud puffs=10] {Cloud};
\node[cross out, draw] at (0,0) {};
\node[strike out, draw] at (0,0) {};
```

## Arrows

```latex
\usetikzlibrary{arrows.meta}

% Arrow tips (arrows.meta syntax)
\draw[->] (0,0) -- (1,0);              % default
\draw[-Stealth] (0,0) -- (1,0);        % filled triangle
\draw[-Latex] (0,0) -- (1,0);          % larger filled
\draw[-{Stealth[length=5mm]}] (0,0) -- (1,0);
\draw[{Latex[red]}-{Latex[blue]}] (0,0) -- (1,0);  % colored
\draw[-{>[scale=2]}] (0,0) -- (1,0);

% Common tips: >, Stealth, Latex, To, Circle, Square, |, Hooks
% Modifiers: [length=..], [width=..], [open], [fill=..], [scale=..]
```

## Styles

```latex
% Define in preamble or tikzpicture options
\tikzset{
  mybox/.style = {draw, fill=blue!20, rounded corners, minimum width=2cm},
  myarrow/.style = {-Stealth, thick, red},
  highlight/.style = {fill=yellow, draw=orange, line width=2pt},
}

% Use
\node[mybox] {Box};
\draw[myarrow] (0,0) -- (1,1);

% Style with parameters
\tikzset{
  box/.style = {draw, fill=#1!20, minimum width=1.5cm},
  box/.default = blue,
}
\node[box] {Blue};        % default
\node[box=red] {Red};     % override

% every node/.style applies to all nodes
\begin{tikzpicture}[every node/.style={font=\small}]
```

## Foreach Loops

```latex
% Basic
\foreach \x in {0,1,2,3}
  \draw (\x, 0) circle (0.3);

% With step
\foreach \x in {0,0.5,...,3}
  \fill (\x,0) circle (1pt);

% Multiple variables
\foreach \x/\y in {0/A, 1/B, 2/C}
  \node at (\x, 0) {\y};

% Counter
\foreach \x [count=\i] in {a,b,c,d}
  \node at (\i, 0) {\x};

% Evaluate
\foreach \x [evaluate=\x as \y using \x*\x] in {1,...,5}
  \fill (\x, \y/5) circle (2pt);

% Remember
\foreach \x [remember=\x as \lastx (initially 0)] in {1,...,5}
  \draw (\lastx, 0) -- (\x, 0);
```

## Scopes and Transformations

```latex
\begin{tikzpicture}
  \draw (0,0) -- (1,0);
  
  \begin{scope}[shift={(2,0)}, rotate=45, scale=0.5, red, thick]
    \draw (0,0) -- (1,0) -- (1,1) -- cycle;
  \end{scope}
  
  % Transformations
  % shift={(x,y)}, xshift=1cm, yshift=2cm
  % rotate=45, rotate around={45:(1,1)}
  % scale=2, xscale=2, yscale=0.5
  % xslant=0.5, yslant=0.5
\end{tikzpicture}
```

## Clipping

```latex
\begin{tikzpicture}
  \clip (0,0) circle (1.5cm);
  % Everything below is clipped to the circle
  \fill[blue!30] (-2,-2) rectangle (2,2);
  \draw[step=0.5, gray] (-2,-2) grid (2,2);
\end{tikzpicture}
```

## Layers (backgrounds library)

```latex
\usetikzlibrary{backgrounds}

\begin{tikzpicture}
  \node[draw, fill=white] (A) {Foreground};
  
  \begin{pgfonlayer}{background}
    \fill[yellow!30] (A.south west) rectangle (A.north east);
  \end{pgfonlayer}
\end{tikzpicture}
```

## Pics

```latex
\tikzset{
  myshape/.pic = {
    \draw (-0.5,-0.5) rectangle (0.5,0.5);
    \draw (0,0) circle (0.3);
  }
}

\begin{tikzpicture}
  \pic at (0,0) {myshape};
  \pic[rotate=45, scale=1.5] at (2,0) {myshape};
\end{tikzpicture}
```

## Decorations

```latex
\usetikzlibrary{decorations.pathmorphing, decorations.markings, decorations.text}

% Wavy/zigzag lines
\draw[decorate, decoration={zigzag, amplitude=2mm, segment length=5mm}]
  (0,0) -- (4,0);
\draw[decorate, decoration={snake, amplitude=1mm}]
  (0,0) -- (4,0);
\draw[decorate, decoration={coil, aspect=0.5}]
  (0,0) -- (4,0);
\draw[decorate, decoration={random steps, segment length=3mm}]
  (0,0) -- (4,0);

% Brace
\draw[decorate, decoration={brace, amplitude=5pt}]
  (0,0) -- (3,0) node[midway, above=5pt] {label};

% Text along path
\draw[decorate, decoratio