Gri Commands

1: Introduction
2: Simple example
3: Fancy example
4: Running Gri
5: Programming Gri
6: General Issues
7: X-Y Plots
8: Contour Plots
9: Image Plots
10: Examples
11: Handling Data
12: Gri Commands
13: Gri Extras
14: Evolution of Gri
15: Installing Gri
16: Gri Bugs
17: System Tools
18: Acknowledgments
19: License
20: Newsgroup

21: Concept Index

12.24: The `mask' Command

`mask the image [to {uservalue .u.}|{imagevalue .i.}]'

Examine both the image and the mask pixel by pixel. For any pixels which have a mask value of 1 (which indicates an invalid region of the image), change the image value. If no `to' phrase is present, change the image value to 0 in pixel units. If the `to uservalue .u.' phrase is present, change the pixel to hold the imagevalue that corresponds to this uservalue (see `set image range' command for a discussion of this correspondance). If the `to imagevalue .i.', change the pixel to hold that imagevalue (in range 0 to 255 inclusive for 8-bit images).