Adds arrows to an existing plot (D. B. Baird).

### Options

`WINDOW` = scalar |
Window number for the graphs; default 3 |
---|---|

`COORDINATETYPE` = string token |
Type of coordinate to use for the locations of the arrows (`frame` , `graph` ); default `grap` |

`YUPPER` = scalar |
Maximum vertical coordinate in the frame; default 1 |

`XUPPER` = scalar |
Maximum horizontal coordinate in the frame; default 1 |

`ISTYLE` = string token |
The type of symbol at the start of the arrow (`none` , `open` , `closed` , `circle` ); default `none` |

`ESTYLE` = string token |
The type of symbol at the end of the arrow (`none` , `open` , `closed` , `circle` ); default `open` |

`ISIZE` = scalar |
The size of the symbol at the start of the arrow; default 1 |

`ESIZE` = scalar |
The size of the symbol at the end of the arrow; default 1 |

`IANGLE` = scalar |
The angle in degrees of the starting arrowhead when `ISTYLE` is `open` or `closed` ; default 45 |

`EANGLE` = scalar |
The angle in degrees of the ending arrowhead when `ESTYLE` is `open` or `closed` ; default 45 |

`LAYER` = scalar |
The plot layer for the arrows; default is a new layer above the previous plot items |

### Parameters

`IY` = variates, scalars or factors |
The starting y-positions of the arrows |
---|---|

`IX` = variates, scalars or factors |
The starting x-positions of the arrows |

`EY` = variates, scalars or factors |
The ending y-position of the arrows |

`EX` = variates, scalars or factors |
The ending x-position of the arrows |

COLOUR = variates, scalars, texts or factors |
Colour of the arrows; default `'black'` |

`LINESTYLE` = variates, scalars or factors |
Linestyle of the line in the arrows; default 1 |

`THICKNESS` = variates, scalars or factors |
Thickness of the line in the arrows; default 1 |

`TRANSPARENCY` = variates, scalars or factors |
Transparency of the arrows; default 0 |

### Description

`DARROW`

adds arrows or lines to existing plots. The coordinates defining the start and end points of the arrows are specified by the `IY`

, `IX`

, `EY`

and `EX`

parameters. The `COLOUR`

, `LINESTYLE`

, `THICKNESS`

and `TRANSPARENCY`

parameters specify the colour, linestyle, thickness and transparency (`0`

= opaque – `255`

= completely transparent) of each arrow. These can supply a single value, if all the arrows are to have the same attribute; otherwise, they should supply a structure of the same length as the `IY`

vector.

The `WINDOW`

option specifies the number of the window containing the existing plot. By default, the points defining the arrows are specified in terms of the x- and y-axes in the plot. However, you can set option `COORDINATETYPE=frame`

to define the points relative to the frame. The maximum size of the frame is then defined by the `XUPPER`

and `YUPPER`

options.

The `ISTYLE`

and `ESTYLE`

options control the symbols at the start and end of the arrow, respectively. Similarly, the `ISIZE`

and `ESIZE`

options define the symbol sizes. The `IANGLE`

and `EANGLE`

options control the angle between the two sides at the start and end of the arrowheads. Setting the angles to values greater than 180 (e.g. 315) reverses the direction of the arrowheads.

The `LAYER`

option controls which of the existing items in the plot will be overlaid by the arrows. By default, they overlay all the previous items.

Options: `WINDOW`

, `COORDINATETYPE`

, `YUPPER`

, `XUPPER`

, `ISTYLE`

, `ESTYLE`

, `ISIZE`

, `ESIZE`

, `IANGLE`

, `EANGLE`

, `LAYER`

.

Parameters: `IY`

, `IX`

, `EY`

, `EX`

, `COLOUR`

, `LINESTYLE`

, `THICKNESS`

, `TRANSPARENCY`

.

### Action with `RESTRICT`

Restrictions are ignored.

### See also

Procedures: `DERRORBAR`

, `DFRTEXT`

, `DREFERENCELINE`

, `DTEXT`

.

Commands for: Graphics.

### Example

CAPTION 'DARROW examples' PEN 1; SYMBOL=0 CALCULATE [SEED=467585] (X,Y)[1] = GRUNIFORM(200;0;9) CALCULATE (X,Y)[2] = (X,Y)[1] + GRUNIFORM(NVALUES(X[1]);-1;1) DGRAPH [WINDOW=3; KEY=0; TITLE='Random vectors'] Y=!(1,9); X=!(1,9) DARROW [WINDOW=3; ESTYLE=closed] IY=Y[1]; IX=X[1]; EY=Y[2]; EX=X[2] CALCULATE x1,x2 = 1,8 * COS(C('radians') * !(0,5...355)) CALCULATE y1,y2 = 1,8 * SIN(C('radians') * !(0,5...355)) DGRAPH [WINDOW=3; KEY=0; TITLE='Circle of arrows'] Y=!(-9,9); X=!(-9,9) DARROW [WINDOW=3; ESIZE=1.5; EANGLE=30] IY=y1; IX=x1; EY=y2; EX=x2 DLOAD "Reset graphics" VARIATE x,y; VALUES=!(-1,1,1,-1),!(-1,-1,1,1) CALCULATE xi,xo,yi,yo = 2(x,y)*0.92,1.2,0.92,1.1 FRAME 3; BOX=omit XAXIS 3; action=hide YAXIS 3; action=hide PEN 1; SYMBOL=2; SIZE=2; CFILL='black'; labels=!T(A,B,C,D) DGRAPH [WINDOW=3; KEY=0; TITLE='Balanced loop design'] Y=y; X=x DARROW [WINDOW=3; ESTYLE=closed; ESIZE=3]\ IY=yi; IX=xi; EY=CIRC(yi; 1); EX=CIRC(xi; 1);\ COLOUR='red'; THICKNESS=3 DARROW [WINDOW=3; ESTYLE=closed]\ IY=yo; IX=xo; EY=CIRC(yo;-1); EX=CIRC(xo;-1);\ COLOUR='green'; THICKNESS=3 DLOAD "Reset graphics"