R/qgis_singlesidedbuffer.R

In JanCaha/r_package_qgis: An extension of package "qgisprocess" providing direct R functions for QGIS functions

##' QGIS Algorithm provided by QGIS (native c++) Single sided buffer (native:singlesidedbuffer). This algorithm buffers lines by a specified distance on one side of the line only.  The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded buffers. The join style parameter specifies whether round, miter or beveled joins should be used when buffering corners in a line. The miter limit parameter is only applicable for miter join styles, and controls the maximum distance from the buffer to use when creating a mitered join.
##'
##' @title QGIS algorithm - Single sided buffer
##'
##' @param INPUT `source` - Input layer. Path to a vector layer.
##' @param DISTANCE `distance` - Distance. A numeric value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
##' @param SIDE `enum`  of `("Left", "Right")` - Side. Number of selected option, e.g. '1'. Comma separated list of options, e.g. '1,3'.
##' @param SEGMENTS `number` - Segments. A numeric value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
##' @param JOIN_STYLE `enum`  of `("Round", "Miter", "Bevel")` - Join style. Number of selected option, e.g. '1'. Comma separated list of options, e.g. '1,3'.
##' @param MITER_LIMIT `number` - Miter limit. A numeric value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
##' @param OUTPUT `sink` - Buffered. Path for new vector layer.
##' @param ... further parameters passed to `qgisprocess::qgis_run_algorithm()`
##' @param .complete_output logical specifying if complete out of `qgisprocess::qgis_run_algorithm()` should be used (`TRUE`) or first output (most likely the main) should read (`FALSE`). Default value is `TRUE`.
##' @param .quiet logical specifying if parameter `.quiet` for `qgisprocess::qgis_run_algorithm()` Default value is `TRUE`.
##' @param .messages logical specifying if messages from `qgisprocess::qgis_run_algorithm()` should be printed (`TRUE`) or not (`FALSE`). Default value is `FALSE`.
##'
##' @details
##' ## Outputs description
##' * OUTPUT - outputVector - Buffered
##'
##'
##' @export
##' @md
##' @importFrom qgisprocess qgis_run_algorithm

qgis_singlesidedbuffer <- function(INPUT = qgisprocess:::qgis_default_value(), DISTANCE = qgisprocess:::qgis_default_value(), SIDE = qgisprocess:::qgis_default_value(), SEGMENTS = qgisprocess:::qgis_default_value(), JOIN_STYLE = qgisprocess:::qgis_default_value(), MITER_LIMIT = qgisprocess:::qgis_default_value(), OUTPUT = qgisprocess:::qgis_default_value(),..., .complete_output = .complete_output_option(), .quiet = .quiet_option(), .messages = .message_option()) {

  check_algorithm_necessities("native:singlesidedbuffer")

  if (.messages){
    output <- qgisprocess::qgis_run_algorithm("native:singlesidedbuffer", `INPUT` = INPUT, `DISTANCE` = DISTANCE, `SIDE` = SIDE, `SEGMENTS` = SEGMENTS, `JOIN_STYLE` = JOIN_STYLE, `MITER_LIMIT` = MITER_LIMIT, `OUTPUT` = OUTPUT,..., .quiet = .quiet)
  } else {
    suppressMessages(
      output <- qgisprocess::qgis_run_algorithm("native:singlesidedbuffer", `INPUT` = INPUT, `DISTANCE` = DISTANCE, `SIDE` = SIDE, `SEGMENTS` = SEGMENTS, `JOIN_STYLE` = JOIN_STYLE, `MITER_LIMIT` = MITER_LIMIT, `OUTPUT` = OUTPUT,..., .quiet = .quiet)
      )
  }

  if (.complete_output) {
    return(output)
  }
  else{
    qgisprocess::qgis_extract_output(output, "OUTPUT")
  }
}