[9fans] How to read/write pixels from Memimage

[Pietro Gagliardi]

Hello. I'm porting Bell Labs' Pico image language over to Plan 9 to  
use the Plan 9 native image format (image(6)), and I chose to use  
Memimage. I'd like to know how to get the 32-bit RGB pixel  
information out of a Memimage and into a properly allocated array of  
u32ints, and to do the reverse. Is that possible? Thanks.