plot_rgb_plane: Plots a triangular plot to be filled with pixels and rules
In ropensci/pixelclasser: Classifies Image Pixels by Colour

Description Usage Arguments Details Value See Also Examples

Plots a plane of the two variables selected by the user (r, g or b) and, to serve as visual references, the lines limiting the triangular area that can contain pixels (in blue) and the areas where one of the colour variables has the larger proportion values (in red). Points representing the pixels of a transformed image and lines representing the rules can be later added to the plot using functions plot_pixels() and plot_rule().

plot_rgb_plane(
  x_axis,
  y_axis,
  plot_limits = TRUE,
  plot_guides = TRUE,
  plot_grid = TRUE,
  ...
)

`x_axis`	a character string indicating which colour variable use as x.
`y_axis`	a character string indicating which colour variable use as y.
`plot_limits`	a logical value. When TRUE (default) the limits of the area where the pixels can be found are plotted.
`plot_guides`	a logical value. When TRUE (default) the limits of the area where one variable dominates are plotted.
`plot_grid`	a logical value; if TRUE (default) a grid is added.
`...`	allows passing graphical parameters to the plotting functions.

Graphical parameters can be passed to the function to modify the appearance of the plot. Intended for passing xlim and ylim values to plot the part of the graph where the points are concentrated.

Because the variables were transformed into proportions, the pixel are always inside the triangle defined by the points (0, 0), (1, 0), (0, 1). This triangle is plotted in blue. The point where all three variables have the same value is (1/3, 1/3). The lines joining this point with the centers of the triangle sides divide the areas where one of the three variables has higher proportions than the other two. These lines are plotted as visual aids, so they can be deleted at will.

The function does not return any value.

plot_pixels, plot_rule, define_rule

# Simplest call
plot_rgb_plane("g", "b")

# Plane without the red lines
plot_rgb_plane("g", "b", plot_guides = FALSE)

# Restricting the plane area to show
plot_rgb_plane("g", "b", xlim = c(0.2, 0.5), ylim = c(0.0, 0.33))