Compatibility with Different Display Sizes

1/17/2009 12:54 AM
You can subscribe to this wiki article using an RSS feed reader.

Originally, applications for Palm OS® were designed for 160x160 pixel displays. Newer Palm OS® devices have 320x320 displays, and many applications support both densities. Some applications, mostly games, only run on 320x320 devices.

Windows Mobile™ Pocket PC devices originally had 240x320 (QVGA) displays. The latest models now have 480x640 (VGA) displays.

StyleTap™ Platform does a great job of supporting both old and new Palm OS® applications on both QVGA and VGA Windows Mobile™ Pocket PC devices. Most programs automatically adjust and make the best use of the available display size.

In a few cases, however, you will see some image distortion, because it is not always possible to expand a 160x160 image to a 240x240 space without altering the layout slightly. Usually, the larger image is easier to use and you will quickly get used to the appearance.

But if you need to see the image in its original size, StyleTap platform has a setting that lets you do that. The setting is in the StyleTap Launcher menu, under Options/Display Size. The possible settings are

QVGA device: 100% display size = 240x240 pixels
QVGA device: 66% display size = 160x160 pixels

VGA device: 100% display size = 480x480 pixels
VGA device: 66% display size = 320x320 pixels


Most programs adjust automatically to the available display size. But some programs present a warning message if they detect that they are running with a display size that the program did not expect. For those programs, changing the StyleTap Display Size option to 66% usually fixes the problem.

A few other programs simply fail if the display size is not what they expect. (Usually, these are programs written for Palm OS 5.0 or later that require a 320x320 display.) You must have a VGA device to run these programs, and you should set the Display Size to 66%.

StyleTap will continue to work to minimize the program compatibility problems associated with different display sizes.

Note to Program Developers

There are exciting opportunities for programmers to take advantage of the higher resolution that is available on devices that run StyleTap™ Platform. We encourage developers to contact us for information on how to make the most of this runtime environment.

In terms that you may be familiar with, 160x160 corresponds to low density, 240x240 corresponds to one-and-a-half density, 320x320 corresponds to double density and 480x480 corresponds to triple density.

In addition, for applications that write directly to the screen and do not normally display properly under Palm OS® 5, StyleTap™ Platform transparently provides a virtual 160x160 screen buffer; the image in the virtual screen buffer is automatically scaled to match the current Display Size. Applications designed to run on Palm OS® 5.0 or later may perform direct screen writes as well.