R/chart.R

In ysoh286/xstitch: A package for generating cross stitch charts from images

#' Generate a cross-stitch pattern chart
#' Supply an image and turn it into a cross stitch chart.
#' Currently assumes full stitches.
#' @param imgpath the path of the image to be processed
#' @param height height of chart to be produced by squares (default is 100)
#' @param num number of colours to be used (default is NULL)
#' @param select.col provide a vector of coloured strings (DMC numbers/code)
#' @import graphics
#' @importFrom grDevices col2rgb rgb dev.list dev.new
#' @importFrom stats kmeans
#' @export
chart <- function(imgpath, height = 100, num = NULL, select.col = NULL) {
  img <- magick::image_read(imgpath)

  if (!is.null(height)) {
    img <- magick::image_scale(img, paste0("x", height))
  }

  img <- magick::image_background(img, "white")
  vppm <- magick::image_convert(img, format = "png")
  magick::image_write(vppm, path = "img.png")
  imginfo <- png::readPNG("img.png")

  # remove file
  file.remove("img.png")

  # width and height
  w <- dim(imginfo)[2]
  h <- dim(imginfo)[1]

  if (w * h > 100000) {
    warning("The number of squares to be rendered is over 100,000.
            This may take a while...")
  }
  
  ## IN CASE OF GRAYSCALE (means either imginfo will return 
  ## grayscale / image - 1 / 2 channels rather than 3 or more)
  ## refer to readPNG docs
  
  ## if it is a single channel - set rgb all to be equal
  if (length(dim(imginfo)) == 1) {
    r <- round(imginfo * 255)
    g <- r
    b <- r
  } else if (length(dim(imginfo)) == 2) {
    ## for double channels (most likely grayscale again)
    ## flatten the matrix
    values <- as.vector(imginfo * 255)
    ## assumes grayscale - r / g / b values should be the same
    r <- values
    g <- values
    b <- values
  } else if (dim(imginfo)[3] == 3) {
    # get rgb of pix map
    r <- round(imginfo[,,1] * 255)
    g <- round(imginfo[,,2] * 255)
    b <- round(imginfo[,,3] * 255)
  } else {
     # convert rgba to rgb (from http://marcodiiga.github.io/rgba-to-rgb-conversion)
     # assume background colour is black:
    alpha <- imginfo[,,4]
    r <- round(alpha * imginfo[,,1] * 255)
    g <- round(alpha * imginfo[,,2] * 255)
    b <- round(alpha * imginfo[,,3] * 255)
  }

  dim(r) <- NULL
  dim(g) <- NULL
  dim(b) <- NULL

  if (!is.null(select.col)) {
    index <- match(as.character(select.col), DMCchart[,1])
    reducedChart <- DMCchart[index, ]
  } else {
    reducedChart <- DMCchart 
  }

  dd <- calcColor(reducedChart, r, g, b, num)
  
  ## If we want to assign random colours rather than labelling
  ## as labelling numbers in each square takes alot of time
  ## but this means the colours won't match original
  # if (random.col) {
  #   colorLength <- length(dd$uni[, "bgcolor"])
  #   print(dd$uni[, "bgcolor"])
  #   randomColours <- colors()
  #   rr <- sample(randomColours, colorLength)
  #   dd$cols[,"id"] <- dd$colid
  #   dd$cols[,"colour"] <- rr[dd$cols[,"id"]]
  #   dd$uni[,"colour"] <- rr
  # }
  
  
  plotXMap(dd, w, h)

  chart <- list(colorMap = dd$cols, uniqueColors = dd$uni,
                width = w, height = h, numCount = num)
  invisible(chart)

}