Module plottools.arrows

Drawing arrows.

Axes member functions

• harrow(): draw a horizontal arrow with annotation on the arrow.
• varrow(): draw a vertical arrow with annotation on the arrow.
• point_to(): text with arrow pointing to a point.

Settings

• arrow_style(): generate an arrow style.
• generic_arrow_styles(): some generic arrow styles.

Display

• plot_arrow_styles(): plot names and arrows of all available arrow styles.

Install/uninstall arrows functions

You usually do not need to call these functions. Upon loading the arrows module, install_arrows() is called automatically.

• install_arrows(): install functions of the arrows module in matplotlib.
• uninstall_arrows(): uninstall all code of the arrows module from matplotlib.

Functions

def harrow(ax, x, y, dx, heads='right', text=None, va='bottom', dist=3.0, style='>', shrink=0, lw=1, color='k', head_width=15, head_length=15, transform=None, **kwargs)

Draw a horizontal arrow with annotation on the arrow.

Parameters

ax : matplotlib axes

Axes on which to draw the arrow.

x : float

X-coordinate of starting point of arrow in data coordinates.

y : float

Y-coordinate of starting point of arrow in data coordinates.

dx : float

Length of arrow in data x-coordinates.

heads : string

One of 'left', '<', 'right', '>', 'both', '<>', 'none', or '', Specifies whether to draw the arrow head at the starting point ('left', '<'), at the end ('right', '>'), on both ends ('both', '<>'), or none ('none', '').

text : string

Text for annotating the arrow. A formatting instruction within text (e.g. 'd=%.1fm') is replaced by dx.

va : string

Place text annotation above ('top') or below ('bottom') the arrow.

dist : float

Distance of text annotation from arrow in points.

style : string

Appearance of the arrow head: '>': line arrow, '|>': filled arrow, '>>': fancy arrow, '|': bar

shrink : float

Shrink arrow away from endpoints.

lw : float

Linewidth of line in points.

color : matplotlib color

Color of line and arrow.

head_width : float

Width of arrow head in points.

head_length : float

Length of arrow head in points.

transform : matplotlib.Transform

Defines coordinate system for x, y, and dx. Defaults to data coordinates.

**kwargs : key-word arguments

Formatting of the annotation text, passed on to text(). A zorder argument is also applied to the arrow.

See Also

varrow(), point_to(), arrow_style()

def varrow(ax, x, y, dy, heads='right', text=None, ha='right', dist=3.0, style='>', shrink=0, lw=1, color='k', head_width=15, head_length=15, transform=None, **kwargs)

Draw a vertical arrow with annotation on the arrow.

Parameters

ax : matplotlib axes

Axes on which to draw the arrow.

x : float

X-coordinate of starting point of arrow in data coordinates.

y : float

Y-coordinate of starting point of arrow in data coordinates.

dx : float

Length of arrow in data x-coordinates.

heads : string

One of 'left', '<', 'right', '>', 'both', '<>', 'none', or '', Specifies whether to draw the arrow head at the starting point ('left', '<'), at the end ('right', '>'), on both ends ('both', '<>'), or none ('none', '').

text : string

Text for annotating the arrow. A formatting instruction within text (e.g. 'd=%.1fm') is replaced by dy.

ha : string

Place text annotation to the left ('left') or right ('right') of the arrow.

dist : float

Distance of text annotation from arrow in points.

style : string

Appearance of the arrow head: '>': line arrow, '|>': filled arrow, '>>': fancy arrow, '|': bar

shrink : float

Shrink arrow away from endpoints.

lw : float

Linewidth of line in points.

color : matplotlib color

Color of line and arrow.

head_width : float

Width of arrow head in points.

head_length : float

Length of arrow head in points.

transform : matplotlib.Transform

Defines coordinate system for x, y, and dx. Defaults to data coordinates.

**kwargs : key-word arguments

Formatting of the annotation text, passed on to text(). A zorder argument is also applied to the arrow.

See Also

harrow(), point_to(), arrow_style()

def point_to(ax, text, xyfrom, xyto, radius=0.2, relpos=(1, 0.5), heads='right', style='>', shrink=0, lw=1, color='k', head_width=15, head_length=15, **kwargs)

Text with arrow pointing to a point.

Parameters

ax : matplotlib axes

Axes on which to draw the text and arrow.

text : string

Text placed at xyfrom.

xyfrom : tuple of floats

X- and y-coordinates of text position in data coordinates.

xyto : tuple of floats

X- and y-coordinates of arrow point in data coordinates.

radius : float

Radius of arrow line. Negative curves to the right. Relative to arrow length.

relpos : tuple of floats

X- and y-coordinate of starting point of arrow on text box. Between 0 and 1.

heads : string

One of 'left', '<', 'right', '>', 'both', '<>', 'none', or '', Specifies whether to draw the arrow head at the starting point ('left', '<'), at the end ('right', '>'), on both ends ('both', '<>'), or none ('none', '').

style : string

Appearance of the arrow head: '>': line arrow, '|>': filled arrow, '>>': fancy arrow

shrink : float

Shrink arrow away from endpoints.

lw : float

Linewidth of line in points.

color : matplotlib color

Color of line and arrow.

head_width : float

Width of arrow head in points.

head_length : float

Length of arrow head in points.

**kwargs : key-word arguments

Formatting of the text, passed on to annotate().

See Also

harrow(), varrow(), arrow_style()

def arrow_style(namespace, name, dist=3.0, style='>', shrink=0, lw=1, color='k', head_width=15, head_length=15, **kwargs)

Generate an arrow style.

Add dictionary with name 'as'+name to namespace and to ars

Parameters

namespace : class or None

Namespace to which the generated arrow style is added. If None add arrow style to the main module.

name : string

The name of the arrow style, the prefix 'as' is prepended.

dist : float

Distance of text annotation from arrow in points (for harrow() and varrow()).

style : string

Appearance of the arrow head: '>': line arrow, '|>': filled arrow, '>>': fancy arrow, '|': bar

shrink : float

Shrink arrow away from endpoints.

lw : float

Linewidth of line in points.

color : matplotlib color

Color of line and arrow.

head_width : float

Width of arrow head in points.

head_length : float

Length of arrow head in points.

**kwargs : key-word arguments

Formatting of the annotation text, passed on to text().

See Also

harrow(), varrow(), point_to(), plot_arrow_styles(), generic_arrow_styles()

def generic_arrow_styles(namespace, palette, scale=1)

Some generic arrow styles.

• asLine: simple arrow
• asFilled: arrow with filled head
• asPoint: big arrow with filled head and thick line
• asPointSmall: arrow with filled head and thin line
• asMarker: arrow with filled head, annotation on a transparent background

This is just a suggestion. Copy it and adapt it to your needs!

Parameters

namespace : class or None

Namespace to which the generated arrow style is added. If None add arrow style to the main module.

palette : dict

Color palette. Uses black for the arrow and white for text background.

scale : float

Scale factor for line width, head height and width.

See Also

arrow_style(), plot_arrow_styles()

def plot_arrow_styles(ax, namespace=None)

Plot names and arrows of all available arrow styles.

Parameters

ax : matplotlib axes

Subplot to use for plotting the arrow styles.

namespace : class or None

Namespace on which styles are defined. If None take styles from the main module.

See Also

arrow_style(), generic_arrow_styles()

def install_arrows()

Install functions of the arrows module in matplotlib.

See Also

uninstall_arrows()

def uninstall_arrows()

Uninstall all code of the arrows module from matplotlib.

See Also

install_arrows()

def demo()

Run a demonstration of the arrows module.