ggdebug

The goal of ggdebug is to make it easier to debug functions and ggproto methods in ggplot2.

Installation

You can install the development version from GitHub with:

# install.packages("remotes")
remotes::install_github("paleolimbot/ggdebug")

If you can load the package, you’re all set!

library(ggdebug)

Debugging

Use ggdebug() to debug functions (they can be exported, non-exported, or ggproto methods), use ggundebug() to stop debugging specific functions, and use ggundebug_all() to stop debugging altogether.

# debug ggplot() and GeomPoint$draw_panel()
ggdebug(ggplot, GeomPoint$draw_panel)

# stop debugging functions
ggundebug(ggplot)

# use helpers to debug lots of functions
ggdebug(!!!ggmethods(GeomPoint))

# stop debugging all functions
ggundebug_all()

You can also use this package to install specific versions of ggplot2 from GitHub that link back to the source:

# gginstall("cran/ggplot2")
# gginstall("tidyverse/ggplot2@v3.1.1")
(ggbrowse(FacetWrap$map_data))
#> [1] "https://github.com/tidyverse/ggplot2/blob/1f6f0cb/R/facet-wrap.r#L181-L214"

Tracing

Use ggtrace() (and family) to evaluate abitrary code as functions enter an exit. ggtrace_tree() and ggtrace_stack() are useful shortcut methods.

ggtrace(FacetWrap$map_data, on_enter = quo(print(data)), on_exit = quo(print(data)))
ggplot(mpg, aes(cty, hwy)) + geom_point() + facet_wrap(vars(class))
#> # A tibble: 234 x 11
#>    manufacturer model displ  year   cyl trans drv     cty   hwy fl    class
#>    <chr>        <chr> <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
#>  1 audi         a4      1.8  1999     4 auto… f        18    29 p     comp…
#>  2 audi         a4      1.8  1999     4 manu… f        21    29 p     comp…
#>  3 audi         a4      2    2008     4 manu… f        20    31 p     comp…
#>  4 audi         a4      2    2008     4 auto… f        21    30 p     comp…
#>  5 audi         a4      2.8  1999     6 auto… f        16    26 p     comp…
#>  6 audi         a4      2.8  1999     6 manu… f        18    26 p     comp…
#>  7 audi         a4      3.1  2008     6 auto… f        18    27 p     comp…
#>  8 audi         a4 q…   1.8  1999     4 manu… 4        18    26 p     comp…
#>  9 audi         a4 q…   1.8  1999     4 auto… 4        16    25 p     comp…
#> 10 audi         a4 q…   2    2008     4 manu… 4        20    28 p     comp…
#> # … with 224 more rows
#> # A tibble: 234 x 12
#>    manufacturer model displ  year   cyl trans drv     cty   hwy fl    class
#>    <chr>        <chr> <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
#>  1 audi         a4      1.8  1999     4 auto… f        18    29 p     comp…
#>  2 audi         a4      1.8  1999     4 manu… f        21    29 p     comp…
#>  3 audi         a4      2    2008     4 manu… f        20    31 p     comp…
#>  4 audi         a4      2    2008     4 auto… f        21    30 p     comp…
#>  5 audi         a4      2.8  1999     6 auto… f        16    26 p     comp…
#>  6 audi         a4      2.8  1999     6 manu… f        18    26 p     comp…
#>  7 audi         a4      3.1  2008     6 auto… f        18    27 p     comp…
#>  8 audi         a4 q…   1.8  1999     4 manu… 4        18    26 p     comp…
#>  9 audi         a4 q…   1.8  1999     4 auto… 4        16    25 p     comp…
#> 10 audi         a4 q…   2    2008     4 manu… 4        20    28 p     comp…
#> # … with 224 more rows, and 1 more variable: PANEL <fct>
gguntrace(FacetWrap$map_data)

ggtrace_mdtree(
  !!!ggmethods(FacetWrap),
  combine_vars,
  eval_facets
)

ggplot(mpg, aes(cty, hwy)) + geom_point() + facet_wrap(vars(class))

• Facet$setup_params
• Facet$setup_data
• FacetWrap$compute_layout
  • combine_vars
    • eval_facets
    • eval_facets
• FacetWrap$map_data
  • eval_facets
• Facet$init_scales
• Facet$init_scales
• Facet$train_scales
• Facet$train_scales
• Facet$finish_data
• Facet$draw_back
• Facet$draw_front
• FacetWrap$draw_panels
• Facet$draw_labels

gguntrace_all()

How it all comes together

Or sometimes, you need to debug all of ggplot2.

ggtrace_mdtree(
  print.ggplot,
  ggplot_build,
  ggplot_gtable,
  !!!ggmethods(GeomPoint),
  !!!ggmethods(StatIdentity),
  !!!ggmethods(Layer),
  !!!ggmethods(Layout),
  !!!ggmethods(CoordCartesian),
  !!!ggmethods(FacetWrap),
  !!!ggmethods(ScaleContinuousPosition),
  !!!ggmethods(ScaleContinuous),
  !!!ggmethods(ScaleDiscrete),
  !!!ggmethods(RangeContinuous),
  !!!ggmethods(RangeDiscrete),
  geom_point,
  ggplot.default,
  aes,
  facet_wrap,
  layer,
  guide_axis,
  guides_build,
  guides_train,
  guides_gengrob
)

ggplot(mpg, aes(cty, hwy, col = class)) +
  geom_point() +
  facet_wrap(vars(drv))

• layer
  • Geom$aesthetics
  • Geom$parameters
  • Stat$parameters
  • Geom$parameters
  • Stat$parameters
  • Geom$aesthetics
  • Geom$aesthetics
  • Stat$aesthetics
• ggplot_build
  • Layer$layer_data
  • Layer$setup_layer
  • Layout$setup
    • Facet$setup_params
    • Facet$setup_data
    • Coord$setup_params
    • Coord$setup_data
    • FacetWrap$compute_layout
    • Coord$setup_layout
    • FacetWrap$map_data
  • Layer$compute_aesthetics
  • Scale$transform_df
    • ScaleContinuous$transform
  • Scale$transform_df
    • ScaleContinuous$transform
  • Scale$transform_df
    • ScaleDiscrete$transform
  • Layout$train_position
    • Facet$init_scales
      • ScaleContinuous$clone
    • Facet$init_scales
      • ScaleContinuous$clone
    • Facet$train_scales
      • ScaleContinuous$train
        • RangeContinuous$train
      • ScaleContinuous$train
        • RangeContinuous$train
  • Layout$map_position
    • Scale$get_limits
      • Scale$is_empty
    • ScaleContinuousPosition$map
    • Scale$get_limits
      • Scale$is_empty
    • ScaleContinuousPosition$map
  • Layer$compute_statistic
    • Stat$setup_params
    • Stat$setup_data
    • StatIdentity$compute_layer
  • Layer$map_statistic
    • Layer$compute_geom_1
      • Geom$setup_data
    • Layer$compute_position
    • Layout$reset_scales
      • Scale$reset
        • Range$reset
      • Scale$reset
        • Range$reset
    • Layout$train_position
      • Facet$train_scales
        • ScaleContinuous$train
          • RangeContinuous$train
        • ScaleContinuous$train
          • RangeContinuous$train
    • Layout$setup_panel_params
      • Coord$modify_scales
      • CoordCartesian$setup_panel_params
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
      • CoordCartesian$setup_panel_params
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
      • CoordCartesian$setup_panel_params
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
        • ScaleContinuous$is_discrete
        • ScaleContinuous$dimension
          • Scale$get_limits
            • Scale$is_empty
        • ScaleContinuousPosition$break_info
          • ScaleContinuous$break_info
            • ScaleContinuous$get_breaks
              • Scale$is_empty
            • ScaleContinuous$get_labels
            • ScaleContinuous$get_breaks_minor
        • Scale$axis_order
    • Layout$map_position
      • Scale$get_limits
        • Scale$is_empty
      • ScaleContinuousPosition$map
      • Scale$get_limits
        • Scale$is_empty
      • ScaleContinuousPosition$map
    • Scale$train_df
      • ScaleDiscrete$train
        • RangeDiscrete$train
    • Scale$map_df
      • Scale$get_limits
        • Scale$is_empty
      • ScaleDiscrete$map
    • Layer$compute_geom_2
      • Geom$use_defaults
        • Geom$aesthetics
    • Layer$finish_statistics
      • Stat$finish_layer
    • Layout$finish_data
      • Facet$finish_data
  • ggplot_gtable
    • Layer$draw_geom
      • Geom$handle_na
      • Geom$draw_layer
        • Geom$parameters
        • GeomPoint$draw_panel
          • CoordCartesian$transform
        • GeomPoint$draw_panel
          • CoordCartesian$transform
        • GeomPoint$draw_panel
          • CoordCartesian$transform
    • Layout$render
      • Facet$draw_back
      • Facet$draw_front
      • Coord$render_fg
      • Coord$render_bg
      • Coord$render_fg
      • Coord$render_bg
      • Coord$render_fg
      • Coord$render_bg
      • FacetWrap$draw_panels
        • Coord$render_axis_h
          • guide_axis
        • Coord$render_axis_h
          • guide_axis
        • Coord$render_axis_h
          • guide_axis
        • Coord$render_axis_v
          • guide_axis
        • Coord$render_axis_v
          • guide_axis
        • Coord$render_axis_v
          • guide_axis
        • Coord$aspect
      • Layout$xlabel
        • Scale$make_title
        • ScaleContinuousPosition$sec_name
        • ScaleContinuousPosition$make_sec_title
          • Scale$make_sec_title
        • Scale$axis_order
      • Layout$ylabel
        • Scale$make_title
        • ScaleContinuousPosition$sec_name
        • ScaleContinuousPosition$make_sec_title
          • Scale$make_sec_title
        • Scale$axis_order
      • Coord$labels
      • Layout$render_labels
      • Facet$draw_labels
    • guides_train
      • Scale$make_title
      • Scale$get_limits
        • Scale$is_empty
      • ScaleDiscrete$get_breaks
        • Scale$is_empty
        • Scale$get_limits
          • Scale$is_empty
      • Scale$get_limits
        • Scale$is_empty
      • ScaleDiscrete$map
      • ScaleDiscrete$get_labels
        • Scale$is_empty
        • Scale$get_limits
          • Scale$is_empty
        • ScaleDiscrete$get_breaks
          • Scale$is_empty
          • Scale$get_limits
            • Scale$is_empty
      • ScaleDiscrete$is_discrete
    • Geom$use_defaults
      • Geom$aesthetics
    • guides_gengrob
      • GeomPoint$draw_key
      • GeomPoint$draw_key
      • GeomPoint$draw_key
      • GeomPoint$draw_key
      • GeomPoint$draw_key
      • GeomPoint$draw_key
      • GeomPoint$draw_key
    • guides_build

gguntrace_all()