FS#4764 - H300 reverse colours flash when turning backlight on

Attached to Project: Rockbox
Opened by wehn (wehn) - Saturday, 04 March 2006, 01:02 GMT
Last edited by Christi Scarborough (christi-s) - Sunday, 19 March 2006, 14:51 GMT
Task Type Bugs
Category LCD
Status Closed
Assigned To No-one
Operating System Iriver H300 series
Severity Very Low
Priority Immediate
Reported Version
Due in Version Version 3.0
Due Date Undecided
Percent Complete 100%
Votes 0
Private No


When using a reverese colour scheme such as white on black backround, there is a noticable flash when on turning on the display. This may be because the backlight is turned on before screen is written.

Could the backlight be turned on after drawing the screen? May also be good for other backlit targets.

This task depends upon

Closed by  Peter D'Hoye (petur)
Wednesday, 26 April 2006, 19:26 GMT
Reason for closing:  Fixed
Comment by Christi Scarborough (christi-s) - Sunday, 19 March 2006, 14:50 GMT
Is this still a problem in the latest daily builds?
Comment by wehn (wehn) - Monday, 20 March 2006, 10:29 GMT
I downloaded the 19/3/06 build and made a little video. Constant aperture to prevent emphasising it.

Playing it in slow motion [mplayer -speed 0.1 mvi_4897.avi] seems to show this:
bright (ie high black level) frame with WPS
normal WPS

The one frame that is brighter but has the WPS drawn already. I hadn't tried this on the old builds. Hmm. We may need a faster camera (>15 fps!) to figure out what causes the flash.

It almost seems like it is the delay in the LCD fully darkening after the backlight comes on, even if the LCD is drawn first.
Have you seen this? Only really noticable in the dark, I don't know if it bothers anyone else. :)

Comment by Fredrik Öhrn (ohrn) - Monday, 20 March 2006, 10:31 GMT
I can confirm this on todays build. When turning the backlight on there is a breif white flash before the black background is drawn.
Comment by wehn (wehn) - Monday, 17 April 2006, 10:12 GMT
There may need to be a slight delay between drawing screen, and turning on the backlight to fix this. I suspect the "time to darken" would be different other platforms too.
Comment by Peter D'Hoye (petur) - Wednesday, 26 April 2006, 18:48 GMT
confirmed - only when using dark backgrounds...