weird usages of HP 49 (original)



#5

I was wondering if it was possible, and this would require strange programming, to load an image (jpeg) into the calc's memory and pan on the image (if it was bigger then the screen). If so, would this be very slow? Obviously it would have to be black and white, or at least discernible under those conditions.


#6

It doesn't pan, but I have an animated image of a rotating globe of the Earth for my HP48SX. If that can be done, I'd think a panning image could be done. I don't believe a jpg would be the right format though.


#7

Well, you'd first have to decompress the JPEG image into actual pixels. That's a time-consuming process for native Saturn CPU instruction set. Dropping back into the ARM instruction set for the HP49 may be very useful for speed.

If the image is large and the aspect ratio is same/near to that of HP49 screen, and 8X downsampling would work, then the DC coeffecients of the 8x8 DCT blocks could just be used. This avoids the extra crunching to extract all the other pixels - as the DCT's DC coefficient is just the avg value of all the pixels in that 8x8 block.


Bill Wiese

San Jose, CA USA


1234 to delete

#8

I have my doubts about viewing a jpeg itself on the calculators, but there are utilities for converting between various image formats and graphicss objects for the calculators. Try some searches at http://www.hpcalc.org/.

Regards,
James


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