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geekmaster · 04-20-2012, 08:03 PM

Check out my gamma tutorial in the paldemo post of the "geekmaster formula 42" thread (link in my previous post above). I added a screenshot using my new "lcd gamma" dither table. I did gamma compensation by lowering all threshold values with "pow(dt[c], 1/2.2);", which gives a lot more darks and less brights. The palette screenshot looks almost all black on the kindle eink, but about 50% gray average (viewed at a distance) on an lcd display.

I plan to use the "lcd dither table" to make screenshots of dithered screens. Compare the two different gamma screenshots between the lcd and the kindle eink. The top one looks like average 50% gray on the kindle, but the bottom one looks like averat 50% gray on lcd or crt displays.

If you do dithering for VNC, we need ANOTHER dither table that uses "pow(dt[c],2.2)", to compensate the other direction.

Fun stuff, huh?

EDIT: To use pow(), I added "#include <math.h>", and I compiled with "tccmake paldemo2 -lm", to link in the math library.

04-20-2012, 08:03 PM	#115
geekmaster Carpe diem, c'est la vie. Posts: 6,433 Karma: 10773668 Join Date: Nov 2011 Location: Multiverse 6627A Device: K1 to PW3	Check out my gamma tutorial in the paldemo post of the "geekmaster formula 42" thread (link in my previous post above). I added a screenshot using my new "lcd gamma" dither table. I did gamma compensation by lowering all threshold values with "pow(dt[c], 1/2.2);", which gives a lot more darks and less brights. The palette screenshot looks almost all black on the kindle eink, but about 50% gray average (viewed at a distance) on an lcd display. I plan to use the "lcd dither table" to make screenshots of dithered screens. Compare the two different gamma screenshots between the lcd and the kindle eink. The top one looks like average 50% gray on the kindle, but the bottom one looks like averat 50% gray on lcd or crt displays. If you do dithering for VNC, we need ANOTHER dither table that uses "pow(dt[c],2.2)", to compensate the other direction. Fun stuff, huh? EDIT: To use pow(), I added "#include <math.h>", and I compiled with "tccmake paldemo2 -lm", to link in the math library. Last edited by geekmaster; 04-20-2012 at 08:07 PM.