scatterSymbols {svgtools}

Adjust symbols of a scatter plot

Description

Adjusts the horizontal (XML attributes 'x', 'x1', 'x2', 'cx' etc.) and vertical (XML attributes 'y', 'y1', 'y2', 'cy' etc.) positions of symbols (see details). Positions are calculated relative to a given frame (XML element of type 'rect') and the position of a data value within the minimum and maximum of two given scales for x- and y-axis. This process is called scaling.
In preparation, it is necessary to name a group (set attribute 'id' of XML element of type 'g') of symbols. Symbols are automatically duplicated or removed to match the amount of data values.

Usage

scatterSymbols(
  svg,
  frame_name,
  group_name,
  scale_real_x,
  scale_real_y,
  values,
  symbol_type
)

Arguments

svg

XML document with SVG content

frame_name

Name (attribute 'id') of frame (XML element 'rect') for positioning of elements.

group_name

Name (attribute 'id') of group (XML element 'g') with symbols.

scale_real_x

Numeric vector (e.g. c(0,100)) of arbitrary length for x-axis. Only minimum and maximum are used for scaling of values.

scale_real_y

Numeric vector (e.g. c(0,100)) of arbitrary length for y-axis. Only minimum and maximum are used for scaling of values.

values

Dataframe or matrix with numeric vectors. First column corresponds to x-axis. Second column corresponds to y-axis.

symbol_type

Character value. Accepts 'circle', 'rect', 'polygon', 'linegroup', 'path', or 'guess' for guessing of type; see details.

Details

Symbols may be prepared in the SVG file in any amount. But be aware that the function will simply duplicate the first one (in the group) or remove the last ones to match the amount of data values. When, for example, you need to have different colors for different subgroups of cases, prepare several groups of symbols and call this function for each of them.
The function currently supports the following symbol_types:

• circle: XML elements of type 'circle'. Attributes 'cx' and 'cy' are adjusted.

• rect: XML elements of type 'rect'. Attributes 'x' and 'y' are adjusted.

• polygon: XML elements of type 'polygon'. Attribute 'points' is adjusted so that the centroid of the shape matches the scaled value positions on the chart.

• linegroup: XML elements of type 'g' that contain elements of type 'line'. Attributes 'x1', 'x2', 'y1' and 'y2' of those lines are adjusted so that the mean x- and y-coordinate of all lines in the group matches the scaled value positions on the chart.

• path: XML elements of type 'path'. The first command of attribute 'd' is adjusted. The center of path is defined as the midpoint between minimum and maximum x- and y-coordinates of the shape.

Value

XML document with SVG content

Examples

#read SVG file
fpath <- system.file("extdata", "fig13.svg", package="svgtools")
svg <- read_svg(file = fpath)

#scatter symbols
set.seed(12345)
df <- data.frame(g=rep(1:4,10), x=rnorm(40,500,75), y=rnorm(40,500,75))
df[df$g==1,]$x <- df[df$g==1,]$x-35
df[df$g==2,]$y <- df[df$g==2,]$y-35
df[df$g==3,]$x <- df[df$g==3,]$x+35
df[df$g==4,]$y <- df[df$g==4,]$y+35
svg <- scatterSymbols(svg = svg, frame_name = "frame", group_name = "gA", 
                      scale_real_x = c(250,750), scale_real_y = c(250,750), 
                      values = df[df$g==1,2:3], symbol_type = "rect")
svg <- scatterSymbols(svg = svg, frame_name = "frame", group_name = "gB", 
                      scale_real_x = c(250,750), scale_real_y = c(250,750), 
                      values = df[df$g==2,2:3], symbol_type = "circle")
svg <- scatterSymbols(svg = svg, frame_name = "frame", group_name = "gC", 
                      scale_real_x = c(250,750), scale_real_y = c(250,750), 
                      values = df[df$g==3,2:3], symbol_type = "polygon")
svg <- scatterSymbols(svg = svg, frame_name = "frame", group_name = "gD", 
                      scale_real_x = c(250,750), scale_real_y = c(250,750), 
                      values = df[df$g==4,2:3], symbol_type = "linegroup")