R/render_resized.R

In rayimage: Image Processing for Simulated Cameras

#'@title Resize Image
#'
#'@description Resizes an image or a matrix, using bilinear interpolation.
#'
#'@param image 3-layer RGB/4-layer RGBA array, `rayimg` class, or filename of an image.
#'@param mag Default `1`. Amount to magnify the image, preserving aspect ratio. Overridden if
#'`dim` is not `NULL`.
#'@param dims Default `NULL`. Exact resized dimensions.
#'@param filename Default `NULL`. The filename of the image to be saved. If this is not given, the image will be plotted instead.
#'@param preview Default `FALSE`. Whether to plot the convolved image, or just to return the values.
#'@param method Default `trilinear`. Filters to up/downsample the image. Options: `bilinear`, `box`, `trilinear`,
#' `catmull`, `mitchell`.
#'@return A `rayimg` RGBA array.
#'@export
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#'#Plot the image with a title
#'dragon |>
#'  render_title("Dragon", title_offset=c(10,10), title_bar_color="black",
#'            title_size=20, title_color = "white") |>
#'  plot_image()
#'#Half of the resolution
#'render_resized(dragon, mag = 1/2) |>
#'  render_title("Dragon (half res)", title_offset=c(5,5), title_bar_color="black",
#'            title_size=10, title_color = "white") |>
#'  plot_image()
#'#Double the resolution
#'render_resized(dragon, mag = 2) |>
#'  render_title("Dragon (2x res)", title_offset=c(20,20), title_bar_color="black",
#'            title_size=40, title_color = "white") |>
#'  plot_image()
#'#Specify the exact resulting dimensions
#'render_resized(dragon, dim = c(160,320)) |>
#'  render_title("Dragon (custom size)", title_offset=c(10,10), title_bar_color="black",
#'            title_size=20, title_color = "white") |>
#'  plot_image()
render_resized = function(
  image,
  mag = 1,
  dims = NULL,
  filename = NULL,
  preview = FALSE,
  method = "tri"
) {
  temp_image = ray_read_image(image)
  orig_dims = dim(temp_image)[1:2]
  downscale = if (!is.null(dims)) {
    any(dims[1:2] < orig_dims)
  } else {
    isTRUE(mag < 1)
  }
  use_bilinear = method %in% c("bi", "bilinear") && !downscale
  if (!use_bilinear && method %in% c("bi", "bilinear")) {
    method = "box"
  }
  #Check if file or image before below:
  imagetype = attr(temp_image, "filetype")
  img_source_linear = attr(temp_image, "source_linear")
  colorspace = attr(temp_image, "colorspace")
  white_current = attr(temp_image, "white_current")

  if (use_bilinear) {
    if (!is.null(dims)) {
      dims = dims[1:2] / dim(temp_image)[1:2]
    }
    temp_list = list()
    if (length(dim(temp_image)) == 3) {
      channels = dim(temp_image)[3]
      for (i in seq_len(channels)) {
        if (is.null(dims)) {
          temp_list[[i]] = resize_image(temp_image[,, i], mag)
        } else {
          x1 = seq(1, nrow(temp_image), length.out = nrow(temp_image) * dims[1])
          y1 = seq(1, ncol(temp_image), length.out = ncol(temp_image) * dims[2])
          temp_list[[i]] = resize_image_xy(temp_image[,, i], x1, y1)
        }
      }
      temp_image = array(
        0,
        dim = c(nrow(temp_list[[1]]), ncol(temp_list[[1]]), channels)
      )
      for (i in seq_len(channels)) {
        temp_image[,, i] = temp_list[[i]]
      }
    } else {
      if (is.null(dims)) {
        temp_image = resize_image(t(flipud(temp_image)), mag)
      } else {
        x1 = seq(1, nrow(temp_image), length.out = nrow(temp_image) * dims[1])
        y1 = seq(1, ncol(temp_image), length.out = ncol(temp_image) * dims[2])
        temp_image = resize_image_xy(t(flipud(temp_image)), x1, y1)
      }
    }
  } else {
    method = tolower(method)
    method = switch(
      method,
      "default" = 0,
      "box" = 1,
      "triangle" = 2,
      "tri" = 3,
      "trilinear" = 3,
      "cubic" = 3,
      "catmull" = 4,
      "mitchell" = 5,
      3
    )
    if (is.null(dims)) {
      dims = mag * dim(temp_image)[1:2]
    }
    temp_list = list()
    if (length(dim(temp_image)) == 3) {
      for (i in seq_len(dim(temp_image)[3])) {
        temp_list[[i]] = resize_matrix_stb(
          unclass(temp_image[,, i]),
          dims[1],
          dims[2],
          method
        )
      }
      temp_image = array(0, dim = c(dims[1], dims[2], dim(temp_image)[3]))
      for (i in seq_len(dim(temp_image)[3])) {
        temp_image[,, i] = temp_list[[i]]
      }
    } else {
      bare_matrix = unclass(temp_image)
      temp_image = resize_matrix_stb(
        bare_matrix,
        dims[1],
        dims[2],
        method
      )
    }
  }
  temp_image = ray_read_image(
    temp_image,
    filetype = imagetype,
    source_linear = img_source_linear,
    assume_colorspace = colorspace,
    assume_white = white_current
  )
  handle_image_output(temp_image, filename = filename, preview = preview)
}