How to load a large image for display on the Palm PDA

[rberger]

Hello:

I have a large image I would like to display on LV for Palm PDA. The documentation states there should be a 64K chunk limitation for VIs to compile on the Palm. Therefore, I decided to break this image up into 2D arrays of less than 64K per subVI. My 3.2 Meg image therefore has about 224 2D array subVIs. My motivation is to somehow use the build array function (with concatenate inputs) to reconstruct the image at runtime. I can compile each 2D array subVI as a test, but my attempt to reassemble and compile is futile. When I try to use the build array with only 8 of these subVIs in a top level VI the compiler complains its still too big of a VI. Using get info, memory for this top level states total ~2
3K of memory usage.

So can someone help me with this problem. Is there another way to load this size of an image into memory so I can display it on a picture control?

BTW, this can build on LV for PocketPC.

Thank you
Robert

[KileenC]

Hi Robert,

You are correct in that one of the limitations of the Palm OS is that files cannot be larger than 64 KB in size (as stated on page 5-3 of the LabVIEW PDA Module User Manual). The suggested workaround is indeed to have a top-level PDA VI that calls subVIs, and this top-level VI can then have a total file size larger than 64 KB.

My suspicion is that with the picture control on the Palm OS, even if you are breaking up the image into smaller subVIs, the process of building the array to reassemble the picture is still forcing the Palm to allocate memory for each of those 2D array subVIs to place on the top-level VI's picture control
and thus causing the Palm to complain about not having enough memory. The LabVIEW PDA User Manual also states that "There is a total limit of 64 KB on all front panel array data". Thus, when you are trying to use the build array on the top-level VI, the 64 KB limit on front panel array data is still being exceeded -- even with only 8 of these subVIs.

The following KnowledgeBase article KB 38EJRHFQ: How Do I Put a Picture or Image on My LabVIEW PDA for Palm Front Panel? states that as a workaround, you can shrink the size of your image by using 4-bit or 1-bit data instead of the standard 8-bit pixmap representation.

This is really just a limitation of the Palm OS and the fact that there is simply no way of displaying that much front panel information for your picture. Either way, you would need to build up the array of pixels for your bitmap, and for a 3.2 MB image, I don
't believe there is any way for the Palm OS PDA to display the image in its entire at once.

Sorry about that...

Kileen C.
National Instruments