bm_print {bittermelon}

Print bitmap objects

Description

bm_print() prints a representation of the bitmap object to the terminal while bm_format() returns just the character vector without printing it. They are wrappers around as_bm_bitmap() / as_bm_pixmap() and format.bm_bitmap() / format.bm_pixmap().

Usage

bm_print(x, ...)

bm_format(x, ...)

Arguments

x

A bitmap object that can be cast by as_bm_pixmap() to a bm_pixmap() object.

...

Passed to format.bm_pixmap() or format.bm_bitmap() depending on the class of x.

Value

A character vector of the string representation (bm_print() returns this invisibly). As a side effect bm_print() prints out the string representation to the terminal.

Fonts and terminal settings

Printing bitmaps/pixmaps may or may not look great in your terminal depending on a variety of factors:

• The terminal should support the Unicode - UTF-8 encoding. We use cli::is_utf8_output() to guess Unicode support which in turn looks at getOption("cli.unicode") and l10n_info().

• The terminal should support ANSI sequences and if it does it should support many colors.

  • We use cli::num_ansi_colors() to detect number of colors supported. num_ansi_colors() detection algorithm is complicated but it first looks at getOption("cli.num_colors").

  • If cli::num_ansi_colors() equals 16777216 then your terminal supports 24-bit ANSI colors.

  • If using the Windows Command Prompt window you may need to enable ANSI sequences support by doing ⁠REG ADD HKCU\CONSOLE /f /v VirtualTerminalLevel /t REG_DWORD /d 1⁠ from the command-line or running regedit (Registry Editor) and go to ⁠Computer\HKEY_CURRENT_USER\Console⁠ and set VirtualTerminalLevel to 1.

• The font used by the terminal should be a monoscale font that supports the Block Elements Unicode block.

• The terminal text settings should have a cell spacing around 1.00 times width and 1.00 times height. For terminals configured by CSS styles this means a line-height of around 1.0.

See Also

.S3method() to register this as the print method for a non-bittermelon bitmap class.

Examples

font_file <- system.file("fonts/spleen/spleen-8x16.hex.gz", package = "bittermelon")
font <- read_hex(font_file)
capital_r <- as_bm_bitmap("R", font = font)
bm_print(capital_r)

corn_r <- as.raster(farming_crops_16x16()$corn$portrait)
if (cli::is_utf8_output() && cli::num_ansi_colors() >= 256L) {
  bm_print(corn_r, compress = "v") 
}

if (requireNamespace("magick", quietly = TRUE) &&
    cli::is_utf8_output() && 
    cli::num_ansi_colors() > 256L) {
  rose_mi <- magick::image_read("rose:")
  bm_print(rose_mi, compress = "v") 
}

## Not run: # Change other bitmap classes' `print()` to use `bm_print()` instead
  options(bittermelon.compress = "vertical",
          bittermelon.downscale = requireNamespace("magick", quietly = TRUE))
  for (cl in c("glyph_bitmap", "magick-image", "nativeRaster", "pixeltrix",
               "pixmapGrey", "pixmapIndexed", "pixmapRGB", "raster")) {
    .S3method("print", cl, bittermelon::bm_print)
  }

## End(Not run)