Create a Geometry form a Imagemagick / X11 geometry string.
Initialize with width heigt and offsets.
Calculate the absolute width and height based on the flags, and the profided width and height.
Convert Geometry into a Imagemagick geometry string.
Resize only if the image is greater than the width and/or height.
Retain the aspect ratio.
Resize only if the image is smaller than the width and/or height.
The specified width and/or height is the minimum value.
The width and/or height are percentages of the original.
Geometry provides a convenient means to specify a geometry argument.