LCD Contrast and Grey Texture Drawing

One of the Newton 2.x OS Q&As
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This document was exported on 7/23/97.

LCD Contrast and Grey Texture Drawing (11/10/93)

Q: An artist working with me did a wonderful job rendering a 3D look using several different dithered grey textures. The problem is that when her image is displayed on a Newton display everything on the screen dims. Is it possible that the image causes too much display current to maintain contrast?

A: What you're seeing is a well-known problem with LCD displays, and there's not a lot you can do about it. It's especially aggravated by large areas of 50% dithered gray (checkerboard) patterns, but the light gray and dark gray patterns also cause some of it.

The user interface of the Newton OS deliberately avoids 3-D styling and 50% dithered grays as much as possible for this reason. If you know your application is going to display large gray areas, you can adjust the contrast yourself on some hardware devices. There's a global function, SetLCDContrast, to do just that. However, changing the contrast with no end user control is not considered a good user-interface practice.