[Jaffa Software]

Wednesday 2 November 2011

Colour operator logos on N9 lock screen

Nick Larsson (aka frals) has posted an article on adding a small (120x120px) logo to your N9 lock screen.

The N9 has a PenTile AMOLED screen, but is configured to avoid the colour fringing problems that affected the Android-based Nexus One. However, when the lock screen is displayed, certain bit patterns produce colours:

Photo of N9 lock screen with colour image

John Hutchison's Generating false colour images on the Nexus One using only grayscale pixels contains source code and examples.

The above photo was created by taking a 120x120px cut from the example rainbow image and setting it as the logo:

Greyscale section of rainbow

The same section, viewed on a Nexus One looks like:

Greyscale section of rainbow

As you can see, the colour mapping isn't the same (meaning new reference images need to be generated). However, you'll see it is possible to have colour logos on the lockscreen. Hopefully someone will take it forward, perhaps Nick can update his tool to do colour mapping; or someone can post the reference images so that the Java source code from Luke Hutchison can work.


  1. Can't you just use a color PNG there? AFAIK the lock screen is only a low-powered mode of the AMOLED screen, but the pixels themselves don't change, so they are still able to do colors (in fact, due to the low-powered mode, it's easier to spot the colors at the edges of the clock numbers compared to the full-power mode).

  2. You can use a colour image, but the colours are flattened into a much darker, more limited palette.

    Some combination of identifying which colours can be used; and what dithering effects will generate certain colours could give the best effect.

    BTW, do you know if it's possible to get into this low-power mode in "normal" apps? That'd be useful for generating the colour mapping and Bedside :-)