Select image regions by plotting interactive polygons#

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Last Updated: Mar 11, 2023

Description#

Plot interactive polygons on an image and retrieve the polygons coordinates.

Usage#

plotInteractivePolygons(x, width = "auto", height = "auto", ...)

Arguments#

x

A ‘ggplot’ or ‘rast’ plot object to draw polygons on

width, height

An integer, defining the width/height in pixels.

...

Graphical parameters passed on to ‘polygon’ or ‘geom_point’.

Value#

A ‘data.table’ containing x,y coordinates from the plotted polygons.

Examples#

## Not run:
# Using a ggplot2 plot
library(ggplot2)
df <- data.frame(x = 1:5, y = 1:5)
my_plot <- ggplot(df, aes(x,y)) + geom_point()
plotInteractivePolygons(my_plot)

# Using a terra rast image
library(terra)
r = rast(system.file("ex/elev.tif", package="terra"))
plotInteractivePolygons(r)
plotInteractivePolygons(r, border = "red", lwd = 2)

# Using an image contained in Giotto object
library(Giotto)
my_spatPlot <- spatPlot2D(gobject = my_giotto_object,
                          show_image = TRUE,
                          point_alpha = 0.75,
                          save_plot = FALSE)
plotInteractivePolygons(my_spatPlot, height = 500)
my_polygon_coordinates <- plotInteractivePolygons(my_spatPlot, height = 500)

## End(Not run)