image_crop_textlines: Crop out areas with text lines from an image

In DIGI-VUB/madoc.utils: Tools for interacting with Madoc

Crop out areas with text lines from an image

Description

Crop out areas with text lines from an image

Usage

image_crop_textlines(
  image,
  geometries,
  color = "royalblue",
  border = "10x10",
  overview = TRUE,
  max_width = +Inf,
  trace = FALSE
)

Arguments

image	image either an object of class magick-image or a path to an image file on disk
geometries	a data.frame with columns width, height, x_left, y_top indicating the areas to extract from the image
color	color to use for adding a border in the overview image. Defaults to 'royalblue'.
border	border pixels to using in the overview image. Defaults to 10x10 pixel borders.
overview	logical indicating to add the overview image of all area's below each other. Defaults to TRUE.
max_width	maximum width of the overview image. Defaults to +Inf
trace	logical indicating to trace progress

Value

a list with elements areas and overview where overview is a magick-image with stacked image lines and areas is a list of magick-image's, one for each text line.
In case overview is set to FALSE the return value is only the list of stacked image lines.

Examples

library(magick) 
library(data.table)
path     <- system.file(package = "madoc.utils", "extdata", "alto-example.xml")
x        <- read_alto(path)
x$width  <- as.integer(x$WIDTH)
x$height <- as.integer(x$HEIGHT)
x$x_left <- as.integer(x$HPOS)
x$y_top  <- as.integer(x$VPOS)
x           <- subset(x, grepl(ID, pattern = "line"))
rownames(x) <- x$ID

img      <- system.file(package = "madoc.utils", "extdata", "alto-example.jpg")
img      <- image_read(img)
areas    <- image_crop_textlines(img, x, color = "red")
areas$overview
areas$areas

DIGI-VUB/madoc.utils documentation built on Sept. 14, 2022, 3:03 p.m.