DESCRIPTION
Not yet written yet, sorry...
$p The source pixels (1..4 bytes per pixel, depending on format). Use
like this:
$p*3.5 # the return value is the result
$P The source pixels without alpha. Use it like this:
$P *= 0.5; $p # modify $P inplace, return also modified $p as result
$x A two-dimensional vector containing the x-coordinates of each point
in the current tile:
$x = (zeroes(long,$w)->xvals + $destination->x)->dummy(1,$h)->sever;
$y A two-dimensional vector containing the y-coordinates of each point
in the current tile:
$y = (zeroes(long,$h)->xvals + $destination->y)->dummy(0,$w)->sever;
$bpp
The bytes per pixel value of the destination area.