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overrgb - Man Page

composites an RGBA nrrd over a background color (or image)


overrgb -i <nin> [-c <contrast>] [-cfp <fixed point>] [-g <gamma>] [-b <background>] [-bi <nbg>] -o <filename>


Composites an RGBA nrrd over a background color (or image), after doing gamma correction, then quantizes to an 8-bit image. Actually, the input nrrd can have more than 4 values per pixel, but only the first four are used. If the RGBA nrrd is floating point, the values are taken at face value; if it is fixed point, the values interpreted as having been quantized (so that 8-bit RGBA images will act as you expect). When compositing with a background image, the given background image does not have to be the same size as the input image; it will be resampled (with linear interpolation) to fit.


-i <nin>

input nrrd to composite (nrrd)

-c <contrast>

contrast to apply to RGB values, before gamma. “0.0” means no change, “1.0” means thresholding, “-1.0” means a complete washout. (double); default: “0.0

-cfp <fixed point>

component level that doesn’t change with contrast (double); default: “0.5

-g <gamma>

gamma to apply to image data, after contrast (double); default: “1.0

-b <background>

background color to composite against; white is 1 1 1, not 255 255 255. (3 doubles); default: “0 0 0

-bi <nbg>

8-bit RGB background image to composite against (nrrd); default: “”

-o <filename>

file to write output PPM image to (string); default: “-

See Also

gprobe(1), ilk(1), mrender(1), miter(1), nrrdSanity(1), puller(1), tend(1), unu(1), vprobe(1)

Referenced By

gprobe(1), ilk(1), miter(1), mrender(1), nrrdSanity(1), puller(1), tend(1), unu(1), vprobe(1).

April 2021