🚀 go-pugleaf

In article <SLEHAR.92Aug7111245@kendall.bu.edu> slehar@kendall.bu.edu (Steve Lehar) writes:
>
>I    have given much  thought to    an agonizing  trade-off in   image
>processing   loops in   c,  and have   not  come   up with a   totally
>satisfactory solution-   I wonder  whether    anyone  has  any    good
>suggestions.
>
>    yskip = 0;
>    for(y=0;y<ysize;y++){
>      for(x=0;x<xsize;x++){
>	*(data+yskip+x) = ...
>      }
>      yskip += xsize;
>    }
>
>Now this solution works o.k, and  that  is basically  what I am using.
>But the code looks very messy- maybe not  so bad in  this example, but
>when you start adding extra inner loops like for an image convolution,

The above code is close to what I am doing - if I process pixels sequentially,
I keep a pointer to the current pixel, and increment it as I go along:

cur = data;

for (y = 0; y < ysize; y++) {
  for (x = 0; x < xsize; x++, cur++) {
    cur = whatever;
  }
}

You can also do this if you wander around the image - to go to next or 
previous pixel, just increment or decrement cur, to go to the pixel below
or above, just add or subtract the width of the bitmap. Of course, when
you travel around like this, make sure you don't step out of bounds.

Michal