[shosaco]

Summary

Allows col.color argument to reference categorical columns, not just color codes. The package then automatically assigns colors from a palette based on the unique values in that column.

Changes

• R/set_colors.R: Added color detection logic using col2rgb() to distinguish between RGB/hex colors and categorical data. When categorical data is detected, maps categories to colors from RColorBrewer's Set3 palette.
• R/fix_columns.R: Preserves color_is_categorical attribute through the data processing pipeline and maintains .col_category for reference.
• R/plot_ggplot.R: Updated to use colors directly with I() or without I(), depending if color names/codes given or not.
• R/plot_plotly.R: Updated to use colors directly with I() or without I(), depending if color names/codes given or not.
• R/plot_highchart.R: Updated to use colors directly with I() or without I(), depending if color names/codes given or not.
• tests/testthat/test-set_colors.R: Added 11 unit tests covering valid colors, named colors, categorical data, NA values, and edge cases.

Benefits

• Users can now color plots by categorical attributes without providing explicit color codes
• Automatic color palette generation for categorical data
• Consistent behavior across all three plotting engines (plotly, ggplot2, highcharts)

Example

pres <- data.frame(
  Position = c("President", "Vice", "President"),
  Name = c("Washington", "Adams", "Jefferson"),
  start = c("1789-03-29", "1797-02-03", "1801-02-03"),
  end = c("1797-02-03", "1801-02-03", "1809-02-03")
)

# Color by Position category - colors auto-assigned
vistime(pres, col.event = "Position", col.group = "Name", 
        col.color = "Position", title = "Presidents")