flickwerk
documentation
introduction
-------------------
flickwerk is a picture mosaic generator. it
creates an approximation of a reference picture by
composing it from a large number of small source
pictures.
legal status
-------------------
© by TEK neoscientists. freeware.
requirements
-------------------
- os3.0 (v39)
- 68020
- guigfx.library v15
- render.library v29
recommended:
- fast CPU
- 24bit datatypes installed and properly working
- a large number of pictures
warning
-------------------
this software will overwrite the filecomments of
all source pictures specified.
this behavior cannot be disabled. if you don't
want to lose your source pictures' filecomments,
you must copy these picures to another location
first.
usage
-------------------
flickwerk is a shell command. template:
flickwerk WITH=S0URCEFILES/A/M,
FR0M=REFFILE/A,
T0=0UTFILE/A,
UPDATE/S,
USEKEYS/S,
X=XSEGMENTS/N,
Y=YSEGMENTS/N,
W=PARTWIDTH/N,
H=PARTHEIGHT/N,
FX=ALLOWFLIPX/S,
FY=ALLOWFLIPY/S
WITH=SOURCEFILES/A/M
any number of files, directories, volumes. pattern
matching is supported. directories will be scanned
recursively. warning: any picture encountered will
receive a new filecomment without further notice!
FROM=REFFILE/A
reference picture to be approximated.
TO=OUTFILE/A
filename of the picture to be generated. this
picture will be saved in PPM format.
UPDATE/S
recalculate all keys, no matter if valid keys were
encountered.
USEKEYS/S
do not generate new keys, only use pictures with
already existing keys.
X=XSEGMENTS/N
number of mosaic parts to compose the picture from
(horizontally). defaults to 20.
Y=YSEGMENTS/N
number of mosaic parts to compose the picture from
(vertically). defaults to 20.
W=PARTWIDTH/N
width of a single mosaic part. default: 40
H=PARTHEIGHT/N
height of a single mosaic part. default: 30
FX=ALLOWFLIPX/S
allow horizontal mirroring. note: this option will
double the calculation time.
FY=ALLOWFLIPY/S
allow vertical mirroring. note: this option will
double the calculation time.
how it works
-------------------
1. key-list creation
the supplied directories will be scanned for valid
pictures. any newly encountered picture will be
loaded and reduced to a 360 bit key. if not
already present, the key will encoded to an ascii
string and written to the picture's filecomment.
(valid filecomments will be simply decoded back to
keys.)
2. selection
after building the list of keys, the reference
picture will be loaded and decomposed to the
specified number of mosaic segments (by default
20x20). each segment will be reduced to a 360 bit
reference key. each reference key will be compared
against all keys in the source list.
3. composition
the best matching pictures will be loaded, scaled,
and inserted to their respective locations in the
resulting picture. this picture is finally saved
in PPM format.
notes
----------------------------------
- it may take many hours when you apply flickwerk
to a large number of source pictures the first
time. this depends on the number of pictures,
their sizes, formats, the datatypes used, and the
general system performance. further usage of the
same source material will be much faster.
- it's a good idea to reduce the task priority of
the shell process running flickwerk. use e.g.
changetaskpri -3.
- the source pictures will be cropped to areas
with differing pixels. this will cut off e.g.
black borders.
- you should take care of the reference picture's
aspect ratio. the default settings apply to an
aspect ratio of 4:3. different aspect ratios
require appropriate settings for
PARTWIDTH/PARTHEIGHT or XSEGMENTS/YSEGMENTS.
how to obtain good looking results
----------------------------------
- use a simple and contrastful image as the
reference picture, e.g. a face, a logo.
- allow horizontal and vertical mirroring of the
source pictures, i.e. specify the options FX and
FY.
- the more source pictures you specify, the better
the results you get. 'several thousands' is a good
measure.
- use heterogenous, contrastful source pictures.
do not include workbench patterns and pale stuff
alike.
- use larger numbers for XSEGMENTS and YSEGMENTS.
- the segments are currently not scaled with
interpolation. workaround: specify larger mosaic
parts (PARTWIDTH/PARTHEIGHT), and scale down the
output picture with an image processing software.
author
-------------------
bifat / TEK neoscientists
timm.mueller@darmstadt.netsurf.de
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