Calculates the rowstride that an image created with those values would have. This is useful for front-ends and backends that want to sanity check image values without needing to create them.
Color space for image
Whether the image should have transparency information
Number of bits per color sample
Width of image in pixels, must be > 0
Height of image in pixels, must be > 0
the rowstride for the given values, or -1 in case of error.