XO BW mode (was Re: Guidance sought on collaboration techniques)

david at lang.hm david at lang.hm
Sat Feb 14 17:27:00 EST 2009

On Sat, 14 Feb 2009, Gary C Martin wrote:

> On 14 Feb 2009, at 10:16, Bert Freudenberg wrote:
>> The blur you see in color mode is the DCON performing anti-aliasing
>> by adding color components from the four neighboring pixels into
>> each pixel (e.g., for a red pixel it takes the red components of the
>> surrounding pixels into account, etc).
>> In early DCON drivers it was possible to toggle the anti-aliasing
>> independently of the backlight intensity, so you could clearly see
>> its effect. IIUC this capability has now been coupled to the
>> backlight intensity, which is fine in regular use, but takes away
>> the possibility to easily demonstrate what's happening.
> You do appear to be wrong here. Have access to three XOs here (two MP
> and one B4) that all happily respond to the below command:
>       su
>       echo 1 > /sys/devices/platform/dcon/output
> Disables colour while leaving the backlight setting alone, allowing a
> slightly crisper BW display with backlight on if you want it (close
> look at text edges reminds me of the little colour pixels you get with
> sub-pixel resolution tricks on conventional screens), and:
>       su
>       echo 0 > /sys/devices/platform/dcon/output
> Enables colour while leaving the backlight setting alone, allowing a
> 'colour display' mode when the backlight is potentially off (not a
> very useful combination as it's the backlight that goes through the
> colour layer so you're left looking at a slightly soft BW image from
> just reflected light).

the acceptability of the result is going to depend greatly on what you are 

if you have black text on a white background disabling the color bluring 
mode (anti-aliasing, whatever you want to call it) works pretty well.

however, if you have white text on a black background you end up with a 
rainbow instead of a readable display.

the worst case I saw of this was a graph display (I think it was an audio 
program, but I don't remember which one). it drew a thin white line on a 
black background, when disabling the color mode and leaving the backlight 
on each pixel of the graph was a different color and it really showed up 
that way.

however, when you do the black lines on a white background there appears 
to be enough other colors around that your eyes still see the lighted 
pixels as white and the black lines look pretty good.

David Lang

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