R/utils.R

In leeper/tabulizer: Extract Tables from PDF Documents

localize_file <- function(path, copy = FALSE, quiet = TRUE) {
  if (grepl("^http.*://", path)) {
    tmp <- tempfile(fileext = ".pdf")
    utils::download.file(path, tmp, quiet = quiet, mode = "wb")
    path <- tmp
  } else {
    path <- normalizePath(path.expand(path), mustWork = TRUE)
    if (isTRUE(copy)) {
      filename <- paste0(
        tools::file_path_sans_ext(basename(path)),
        ".pdf"
      )
      filepath <- file.path(tempdir(), filename)
      tmp <- normalizePath(filepath, mustWork = FALSE)
      if (path != tmp) {
        file.copy(from = path, to = tmp, overwrite = TRUE)
      }
      path <- tmp
    }
  }
  path
}

load_doc <- function(file, password = NULL, copy = FALSE) {
  localfile <- localize_file(path = file, copy = copy)
  pdfDocument <- new(J("org.apache.pdfbox.pdmodel.PDDocument"))
  fileInputStream <- new(J("java.io.FileInputStream"), name <- localfile)
  if (is.null(password)) {
    doc <- pdfDocument$load(input = fileInputStream)
  } else {
    doc <- pdfDocument$load(input = fileInputStream, password = password)
  }
  pdfDocument$close()
  doc
}

make_pages <- function(pages, oe) {
  x <- new(J("java.util.ArrayList"))
  lapply(pages, function(thispage) {
    x$add(new(J("java.lang.Integer"), thispage))
  })
  return(x)
}

convert_coordinates <- function(coordinates,
                                dims = NULL,
                                from = c("graphics", "page", "tabula", "java"),
                                to = c("graphics", "page", "tabula", "java")) {
  from <- match.arg(from)
  to <- match.arg(to)

  if (length(coordinates) != 4) {
    stop("Coordinates must have length 4")
  }
  if (to == "page" && is.null(dims)) {
    stop("Page dimensions are required for converting to 'page'")
  }
  if ("graphics" %in% c(to, from)) {
    stop("'graphics' has not been implemented yet")
  }

  # graphics: startx, starty, endx, endy
  # page: top, left, bottom, right
  # tabula: y(top), x(left), width, heigth
  # java: x(left), y(top), width, height
  if (from == "page" && to == "java") {
    coordinates <- c(
      coordinates[c(2, 1)],
      coordinates[4] - coordinates[2],
      coordinates[3] - coordinates[1]
    )
  } else if (from == "page" && to == "tabula") {
    coordinates <- c(
      coordinates[c(1, 2)],
      coordinates[4] - coordinates[2],
      coordinates[3] - coordinates[1]
    )
  } else if (from == "page" && to == "graphics") {
    # TODO
  } else if (from == "java" && to == "page") {
    coordinates <- c(
      coordinates[c(2, 1)],
      dims[2] - coordinates[2] - coordinates[4],
      dims[1] - coordinates[1] - coordinates[3]
    )
  } else if (from == "tabula" && to == "page") {
    coordinates <- c(
      coordinates[c(1, 2)],
      dims[2] - coordinates[1] - coordinates[4],
      dims[1] - coordinates[2] - coordinates[3]
    )
  } else if ((from == "tabula" && to == "java") ||
    (from == "java" && to == "tabula")) {
    coordinates[c(1, 2)] <- coordinates[c(2, 1)]
  } else if (from == "tabula" && to == "graphics") {
    # TODO
  } else if (from == "java" && to == "graphics") {
    # TODO
  }
  coordinates
}

make_area <- function(area = NULL,
                      pages = NULL,
                      npages = NULL,
                      target = c("tabula", "java")) {
  target <- match.arg(target)

  if (!is.null(area)) {
    if (!is.list(area)) {
      stop("'area' must be a list of length 1 or length equal to number of pages")
    }
    if (!is.null(pages)) {
      if ((length(area) == 1L) && (length(pages) != 1L)) {
        area <- rep(area[1], length(pages))
      } else if (length(area) != length(pages)) {
        stop("'area' must be a list of length 1 or length equal to number of pages")
      }
    } else {
      if ((length(area) == 1L) && (npages != 1L)) {
        area <- rep(area[1], npages)
      } else if (length(area) != npages) {
        stop("'area' must be a list of length 1 or length equal to number of pages")
      }
    }
    area <- lapply(area, function(x) {
      if (!is.null(x)) {
        if (target == "tabula") {
          x <- convert_coordinates(x, from = "page", to = "tabula")
          new(
            J("technology.tabula.Rectangle"), .jfloat(x[1]),
            .jfloat(x[2]), .jfloat(x[3]), .jfloat(x[4])
          )
        } else if (target == "java") {
          x <- convert_coordinates(x, from = "page", to = "java")
          new(
            J("java.awt.geom.Rectangle2D$Float"), .jfloat(x[1]),
            .jfloat(x[2]), .jfloat(x[3]), .jfloat(x[4])
          )
        }
      } else {
        NULL
      }
    })
  }
  area
}

make_columns <- function(columns = NULL, pages = NULL, npages = NULL) {
  if (!is.null(columns)) {
    if (!is.list(columns)) {
      stop("'columns' must be a list of length 1 or length equal to number of pages")
    }
    if (!is.null(pages)) {
      if ((length(columns) == 1L) && (length(pages) != 1L)) {
        columns <- rep(columns, length(pages))
      } else if (length(columns) != length(pages)) {
        stop("'columns' must be a list of length 1 or length equal to number of pages")
      }
    } else {
      if ((length(columns) == 1L) && (npages != 1L)) {
        columns <- rep(columns[1], npages)
      } else if (length(columns) != npages) {
        stop("'columns' must be a list of length 1 or length equal to number of pages")
      }
    }
    columns <- lapply(columns, function(x) {
      z <- new(J("java.util.ArrayList"))
      for (i in seq_along(x)) {
        z$add(new(J("java.lang.Float"), rJava::.jfloat(x[i])))
      }
      z
    })
  }
  columns
}