qdata: Create a mutaframe from data with attributes for interaction

Description

This function will first check if the names of some pre-defined row attributes (e.g. .color, .brushed) exist in the column names of the data (will issue an error if they do); then append these columns to the original data to create an augmented data as a mutaframe; in the end add some attributes to the mutaframe for the purpose of interaction (mainly the brush object and the linking specification).

Usage

qdata(data, color = "gray15", border = color, size = 4, brushed = FALSE, visible = TRUE,  ...)

Arguments

data

a data frame (it will be coerced to a data frame if it is not)

color

colors of graphical elements (default dark gray) corresponding to rows of data; it can be a vector of valid R colors, or a name of variable in data (must be either a factor or a numeric variable), or an R expression to calculate colors; color is used to fill the interior of graphical elements

border

colors for the border of graphical elements (e.g. rectangles); NA means to suppress the border

size

sizes of rows; possible values are similar to color, but when using a variable to generate sizes, it must be a numeric variable

brushed

a logical vector indicating which rows are brushed (default all FALSE)

visible

a logical vector indicating which rows are visible (default all TRUE)

Value

a mutaframe with attributes for interaction

Details

When the three arguments color, border and size take values as variable names in data, default palettes will be used to generate colors and sizes. The sequential color gradient palette (seq_gradient_pal) will be applied to continuous variables, and the hue palette (hue_pal) will be applied to categorical variables. The area palette (area_pal) is used to create a size vector when the size variable is continuous. An attribute attr(data, 'Scales') is attached to the returned mutaframe, which will help specific plots to generate legends. This attribute is of the form

list(color =
list(title, variable, palette))

. Whenever any component is changed, the corresponding aesthetics will be updated automatically; for example, if we change the palette function for color, the colors data$.color will be updated using the new palette. See color_pal<- for a list of functions on how to modify scales information.

Examples

Run this code

library(cranvas)
str(tennis)
## more Aces, closer to red; less, blue; higher speed, larger points
qtennis <- qdata(tennis, color = aces, size = serve.speed)

qhist(aces, data = qtennis, main = "Number of Aces")
ls.str(attr(qtennis, "Scales"))  # the scales information

selected(qtennis)[1:10] <- TRUE  # brush the first 10 cases

b <- brush(qtennis)  # the brush object
b$style  # style the brush rectangle
b$style$color <- "brown"  # a brown brush

b$color  # color of brushed elements

b$color <- "cyan"  # brushed elements become cyan


attr(qtennis, "Shadow")  # should be NULL, since no misssing values here


## we can also use the default dark gray
qtennis <- qdata(tennis)
qhist(double.faults, data = qtennis)

cranvas_off()