bm_trim {bittermelon}

Trim bitmaps

Description

bm_trim() trims bm_bitmap() objects reducing the number of pixels. The directions and amount of removed pixels are settable (defaulting to 0L).

Usage

bm_trim(
  bm_object,
  sides = NULL,
  top = NULL,
  right = NULL,
  bottom = NULL,
  left = NULL,
  width = NULL,
  height = NULL,
  hjust = "center-left",
  vjust = "center-top"
)

Arguments

bm_object

Either a bm_bitmap(), bm_list(), or bm_font() object.

sides

If not NULL then an integer vector indicating how many pixels to trim on all four sides. If the integer vector is of length one it indicates the number of pixels for all four sides. If of length two gives first the number for the vertical sides and then the horizontal sides. If of length three gives the number of pixels for top, the horizontal sides, and then bottom sides. If of length four gives the number of pixels for top, right, bottom, and then left sides. This is the same scheme as used by the CSS padding and margin properties.

top

How many pixels to trim the top.

right

How many pixels to trim the right.

bottom

How many pixels to trim the bottom.

left

How many pixels to trim the left.

width

How many pixels wide should the new bitmap be. Use with the hjust argument or just one of either the left or right arguments.

height

How many pixels tall should the new bitmap be. Use with the vjust argument or just one of either the top or bottom arguments.

hjust

One of "left", "center-left", "center-right", "right". "center-left" and "center-right" will attempt to place in "center" if possible but if not possible will bias it one pixel left or right respectively. "centre", "center", and "centre-left" are aliases for "center-left". "centre-right" is an alias for "center-right". Note if "left" we will trim on the right (and vice-versa).

vjust

One of "bottom", "center-bottom", "center-top", "top". "center-bottom" and "center-top" will attempt to place in "center" if possible but if not possible will bias it one pixel down or up respectively. "centre", "center", and "centre-top" are aliases for "center-top". "centre-bottom" is an alias for "center-bottom". Note if "top" we will trim on the bottom (and vice-versa).

Value

Either a bm_bitmap(), bm_list(), or bm_font() object.

See Also

bm_extend(), bm_pad(), and bm_resize().

Examples

 font_file <- system.file("fonts/spleen/spleen-8x16.hex.gz", package = "bittermelon")
 font <- read_hex(font_file)
 capital_r <- font[[str2ucp("R")]]
 print(capital_r, px = c("-", "#"))
 capital_r_trimmed <- bm_trim(capital_r, c(1, 1, 3, 0))
 print(capital_r_trimmed, px = c("-", "#"))