Hello, I would be grateful if some MOS developer would explain me how to change the gfx card channels lookup tables (LUT) by software.
I know it's possible because since old times the cgx monitor editor did allow changing the RGB curves, this feature has then been removed for mos 1.4.x, then introduced back in mos 2.x.
I need to finely calibrate my LCD for graphics works. It's not a too professional monitor, and its gamma and RGB controls are inadeguate to obtain a custom gamma and a sufficiently neutral gray axis. And I need being able to load the curves by program. Every other OS out there allows that, so please don't answer me it's a "private" CGX function...
this is a good question from Elena, I also would need to calibrate my monitor for graphics works. A software solution, including a global CMS system in MorphOS would be great and a big step forward into professionnal graphic art working.
MorphOS 2.0 has public gamma adjustment APIs. Everything is accessible using intuition's monitorclass. The updated includes contain minimum docs on its usage.
Thanks for the reply. I could not figure out the monitorclass stuff etc. I see the method MM_GetDefaultGammaTables. Now I have to experiment with it.
For RMS: yes, an os-level CMS would be nice but I suspect that's one of those least priority things. There's LCMS library port, at least, for CMS at application level
@ Jacadcaps: don't worry, but thanks the same for your offering :) What you told me was enough. I had a look at intuition/monitorclass.h but I read two not so nice things:
The first one is that changing the gamma tables for Ambient screen is not supported (I still have to test what would happen btw, I should boot from mos 2.3 CD because I still have 1.4.5 sorry)
The second one is that just eight-bits values are supported. Calibrating an LCD with 8 bit values is not enough for any serious workflow. I know my gfx card (radeon 9250, I don't know for other models) supports 10 bit curves (ie 10 bit output values for each of 256 R,G,B levels). Since I'm one of those old-school nasty hackers, I promptly set up a little program to load 10 bit curves (at hardware register 0xB8 is located the 32 bit, little endian, sequential 30 bit LUT writing register). The program loads .cal files generated with Argyll and EyeOnePro with a PC. But it's a HACK, period. I use it for my own purposes only and at my own risk.
As end of the story, my suggestion would be 1) to make the cgx/intuition api supporting for example 16 bits gamma curves (that in any case, they will be internally truncated to the effective precision supported by the video hardware and 2) to make the screen mode editor capable of loading external tables (from the format you prefer, which may be a binary or ascii one) and using them as defaults, not just editing the curves graphically.
