ppmshadow

Add simulated shadows to a PPM image. More information: https://netpbm.sourceforge.net/doc/ppmshadow.html.

• Add simulated shadows to a PPM image:

ppmshadow path/to/input_file.ppm > path/to/output_file.ppm

• blur the image by the specified number of pixels:

ppmshadow -b n path/to/input_file.ppm > path/to/output_file.ppm

• Specify the displacement of the simulated light source to the left and the top of the image:

ppmshadow -x left_offset -y top_offset path/to/input_file.ppm > path/to/output_file.ppm