imgdims — guess the width and height of an image file
imgdims uses the autosizing capability of libbn(5) to guess the dimensions (in pixels) of an image. The image size may be expressed either implicitly, by specifying the name of the file; or explicitly, by specifying a number of bytes.
The
-n
option
specifies that
the dimensions should be extracted directly from
file_name,
in the form of any of the standard BRL-CAD command-line options.
Given the
-s
option,
imgdims
ignores any dimensions encoded in
file_name
and uses the size of the file in bytes
to compute the number of pixels in the image
and then guess the image's width and height.
The
-#
option
specifies the size of each pixel (in bytes).
If
file_name
is specified with neither of the
-s and -n
options,
imgdims
tries to extract the dimensions from
file_name,
and if that fails
it computes the image size and guesses the width and height.
If the
-#
option is not specified,
imgdims
determines the pixel size based on the extension on
file_name.
If, additionally,
num_bytes
was specified or
file_name
contains none of the recognized extensions,
imgdims
assumes that there are 3-byte-wide pixels.