Introducing XDA:DevCon – A Conference For Developers By Developers Remember Me? Forgot your password?
 Portal Forum Wiki XDA TV Quick Links
 Print Email

# Gal Note True resolution good calculation

Tip us?
 cribeiro 2nd November 2011, 02:27 AM Senior Member - OP Thanks Meter 6 Posts: 132 Join Date: Sep 2006 Gal Note True resolution good calculation For purpose of understanding imagine two 4" screens both with 800x480 pixels resolution: One is RGB, the other is Pentile GRGB. So, the area of each pixel in each screen is the same, I name it 1 unit-pixel. It happens that this unit-pixel in the RGB screen has 1/3 of area in green (sub-pixel), 1/3 of area in red and 1/3 of area in blue; In Pentile this unit-pixel has 1/3 of area in green and 2/3 of area in red (double area of red); next pixel has 1/3 of area in green and 2/3 in blue (double area of blue). Imagine now one figure with 100 pixels represented in these two screens; imagine now this figure is color green: the number of sub-pixels green is exactly the same in RGB screen as Pentile screen, this is 100 sub-pixels, and also the same in area of green. Imagine now the figure is color red: the number of red sub-pixels in RGB is the same as it was in the green color, this is 100 sub-pixels, but in Pentile the number of red sub-pixels is half of green, this is 50 sub-pixels; however the area of red is exactly the same as it was in green. The same happens in blue color figure. Saying this I guess everybody understands that in a given picture, the area of green, red and blue is exactly the same in both types of screen. It doesn't matter if screen is RGB or Pentile; the area of colored sub-pixels is exactly the same in both types. As in red color, in Pentile screen, is one unit-pixel switch on and next unit-pixel is off, and so on, (but each one with the double in area), if the resolution is a little small like 800x480 in 4" screen, indeed, we yet will be able to see black unit-pixel in the middle of each two red pixels (never forget that color area in each color, is the same as RGB). However this effect is reduced (not completely eliminated) because in the next line the red pixel is advanced of one unit-pixel (alternated), as Pentile in sub-pixels red/blue and lines use alternate technique. Increasing resolution to 1280x720 in 5" screen, the unit-pixels will be so small that we will not be able to see the black unit-pixels switched off in the middle of each two unit-pixels. Furthermore, in real situation, all unit-pixels has the sub-pixels green switched on, this is exactly the same as RGB, and as already said color area is the same. So, we get exactly the same resolution in both systems as the unit-pixels are the same in both systems and each sub-pixel red or blue have the double in area in Pentile to compensate the half number of these sub-pixels. Calculations only with sub-pixels, not taking in account the fact that sub-pixels red and blue are double of area in Pentile, conduces to bad and misleading results. REPLY
 cribeiro 2nd November 2011, 05:53 AM Senior Member - OP Thanks Meter 6 Posts: 132 Join Date: Sep 2006 In Galaxy S (1) red/blue sub-pixel area is double than green sub-pixel to compensatd the half number of red/blue sub-pixels. In Note/Nexus, if the red/blue sub-pixels area is equal to green ones, then the bright of red/blue pixels must be the double of green ones (maintaining the due proportion) in order to maintain the color accuracy as the red/blue number of sub-pixels is half of green. However the resolution maintain equal as RGB because the number of unit-pixels is the same as RGB. So in this case the compensation to equal RGB screen is based in the bright of sub-pixels red/blue instead of double area. REPLY