| Title: | DECWINDOWS 26-JAN-89 to 29-NOV-90 |
| Notice: | See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit |
| Moderator: | STAR::VATNE |
| Created: | Mon Oct 30 1989 |
| Last Modified: | Mon Dec 31 1990 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 3726 |
| Total number of notes: | 19516 |
Hello, I have a question about color division of DECwindows. When DECwindows printscreen print the color screen on a monochrome printer, they set some colors to White and some to Black. For example, RED is Black, Light-Blue is White and so on. Here, I would like to know how to decide colors to White and Black ? Do they have any special way to decide that ? For example, any colors that include RED over 50% or GREEN over 50% are Black. Or any colors that include both Black and Green are White. If there is, please let me know in details. Best Regards.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1151.1 | DECWIN::FISHER | Burns Fisher 381-1466, ZKO3-4/W23 | Fri Jul 21 1989 17:01 | 22 | |
Since no one has answered this in a few hours, I'll put in my 2�, and explain how I did it for monochrome screens getting AllocColor requests. I suspect this is similar to how they do it for monochrome printers. This is also how it is done for monochrome televisions displaying color pictures. Essentially what you do is take a weighted average of the R, G, and B components. Then if you have only black and white, you decide on which one by whether the average is over .5. If more than two monochrome values you scale the average appropriately. The NTSC weighting constants that I used are 39% blue 50% green 11% red That is, if everything is in the range of 0-1, then the monochrome value is (.39*blue + .5*green + .11*red) Burns | |||||
| 1151.2 | Thank you | TKTV05::NAKAMURA_C | TSC/FS/JAPAN | Sun Jul 23 1989 22:43 | 1 |