patterns {grid} R Documentation

## Define Gradient and Pattern Fills

### Description

Functions to define gradient fills and pattern fills.

### Usage

```linearGradient(colours = c("black", "white"),
stops = seq(0, 1, length.out = length(colours)),
x1 = unit(0, "npc"), y1 = unit(0, "npc"),
x2 = unit(1, "npc"), y2 = unit(1, "npc"),
default.units = "npc",
extend = c("pad", "repeat", "reflect", "none"))
radialGradient(colours = c("black", "white"),
stops = seq(0, 1, length.out = length(colours)),
cx1 = unit(.5, "npc"), cy1 = unit(.5, "npc"),
r1 = unit(0, "npc"),
cx2 = unit(.5, "npc"), cy2 = unit(.5, "npc"),
r2 = unit(.5, "npc"),
default.units = "npc",
extend = c("pad", "repeat", "reflect", "none"))
pattern(grob,
x = 0.5, y = 0.5, width = 1, height = 1,
default.units = "npc",
just="centre", hjust=NULL, vjust=NULL,
extend = c("pad", "repeat", "reflect", "none"),
gp = gpar(fill="transparent"))
```

### Arguments

 `colours` Two or more colours for the gradient to transition between. `stops` Locations of the gradient colours between the start and end points of the gradient (as a proportion of the distance from the start point to the end point). `x1, y1, x2, y2` The start and end points for a linear gradient. `default.units` The coordinate system to use if any location or dimension is specified as just a numeric value. `extend` What happens outside the start and end of the gradient (see Details). `cx1, cy1, r1, cx2, cy2, r2` The centre and radius of the start and end circles for a radial gradient. `grob` A grob (or a gTree) that will be drawn as the tile in a pattern fill. `x, y, width, height` The size of the tile for a pattern fill. `just, hjust, vjust` The justification of the tile relative to its location. `gp` Default graphical parameter settings for the tile.

### Details

Use these functions to define a gradient fill or pattern fill and then use the resulting object as the value for `fill` in a call to the `gpar()` function.

The possible values of extend, and their meanings, are:

• [`pad`:] propagate the value of the gradient at its boundary.

• [`none`:] produce no fill beyond the limits of the gradient.

• [`repeat`:] repeat the fill.

• [`reflect`:] repeat the fill in reverse.

To create a tiling pattern, provide a simple grob (like a circle), specify the location and size of the pattern to include the simple grob, and specify `extend="repeat"`.

### Value

A linear gradient or radial gradient or pattern object.

### Warning

Gradient fills and pattern fills are not supported on all graphics devices. Where they are not supported, closed shapes will be rendered with a transparent fill. Where they are supported, not all values of `extend` are supported.

Paul Murrell

### See Also

`gpar`

[Package grid version 4.1.0 Index]