[magick-users] plane group p3m1 in IM

[Rick Mabry]

> The sequence is validated up to point 14) (page 12 in pdf)
> where p3m1_tile_part can not be generated the way it is expected and it
> looks the same like the predecessor image p3m1_tile_part-3
> (15-18 are the same as in pmm and p4m, so they have been validated).
> Any suggestion what went wrong at this point??

You need  * -background transparent * in a few more places.
I added it to your intermediate convert commands and then it worked fine up 
to (14). 

(There is a syntax error involving -crop below, 

> 5)  convert -crop p3m1_G6b.png 1500x1300+0+0 +repage p3m1_G6.png

but that was pretty obvious and not the problem.)

> Comments and hints are highly appreciated.

There is still an error with what follows, I believe. If I represent by "M" 
the tile produced at step (14), what you want next is this flip-flopped 
configuration:

M W
W M

Your next step, however,

15)  convert p3m1_tile_part.png -flop p3m1_tile_part_flop.png 

needs to have a -flip, not a -flop, else you get an "MM" for your row and a 
"WW" for your next row, resulting in 

MM
WW

(You've flipped your flips and flops, which makes it flop. :-))

Anyway, when I made that change everything seemed to give p3m1 as a result, 
although I haven't checked it for "seamlessness". 

This will be a nice utility (or set of utilities if you are doing all 17 
wallpaper groups) when you finish. I recall wanting something like this ages 
ago, but instead labored to make a single example "by hand".

Rick Mabry
Shreveport, LA