Cookbook on making mosaics in the offing.
gtutor_tileit
#@cli gtutor_tileit : 0<=_disrupt<=10,0<_th,0.5<=_spread,0<=_soft,_fillholes,0<=_lightangle<=180,_basec,_offsc
#@cli : Generate a mosaic from a binary black & white image.
#@cli : disrupt=5 Twists and offsets tiles. Suggest 0-10.
#@cli : th=16 Tile height, absolute pixels. Fixme: Effect changes with image size.
#@cli : spread=1.5 Size of gaps between tiles at corners, junctions and runs. Suggest 0-3.
#@cli : soft=0.5 Soften and dull shadows and highlights. Suggest 0-10.
#@cli : fillholes=1 True: Fill gaps. No alpha channel.
#@cli : False: Leave gaps transparent; image has alpha channel.
#@cli : lightangle=45 Degrees: 0-180. Azimuth from where light streams.
#@cli : 45° renders upper left lighting.
#@cli : Provisional coloring. FIXME: sample from input image instead.
#@cli : basec=-60 Provisional: base color, degrees. 0° = green
#@cli : offsc=90 Provisional: offset color, degrees ± angle from basec 0°: no figure-
#@cli : ground distinction.
gtutor_tileit : -check "${1=5}>=0 && $1<=10 && ${2=16}>0 && ${3=1.5}>=0.5 && ${4=0.5}>=0 && isbool(${5=1}) && ${6=45}>=0 && $6<=180" -skip ${7=0},${8=90}
# Selected: black/white binary value shapes. To do: simple color field input images instead
# Parameters
-verbose -
disrupt=$1
th=$2
spread=$3
soft=$4
fillholes=$5
lightangle=$6
basec=$7
offsc=$8
# Outline shapes
+deriche. 1,1,x
+deriche.. 1,1,y
-sqr[^0]
-add[^0]
-fill. 'i>3?1:0'
-channels. 0
-name. outline
# Cost: perturbs distance to outline measure, a basis of tile irregularity
[-1],[-1],1,1
-name. cost
-noise_perlin[cost] {10*$disrupt}
-normalize[cost] 0,{$disrupt/4.0}
# Distance to outline + distance perturbation
+distance[outline] 1,[cost],1
-name. distvar
+distance[outline] 1
+add[-1,-2]
-remove[distvar]
# True distance: basis for marking off distance by tile height
-name. truedistance
# Orient: source of tile rotation
-name.. orienter
-channels[^1] 0
# Make Warper: distorts tile shapes
-gradient[cost] xy
-append[-4,-3] c
-normalize... {-1.5*$disrupt},{1.5*$disrupt}
-name... warper
# Measure out and scribe tile center-to-center lines
-round[truedistance] {$spread*$th}
+deriche. 1,1,x
-deriche.. 1,1,y
-sqr[-2,-1]
-add[-2,-1]
-fill. 'i>0.5?1:0'
-channels[truedistance] 0
# Compute structure tensors
# Make an inpaint patch to
# fill in uncertain ridge values
-structuretensors[orienter] 0
+norm[orienter]
-name. patcher
-fill[patcher] 'i<=2?1:0'
# Patch structure tensors
-inpaint[orienter] [patcher],0,1
-remove[patcher]
# Extract orientation angles
# from structure tensors
-eigen[orienter]
# Plotting field:
[-1],[-1],1,2,'[-1,0]'
-name. plottingfield
# Draw tiles on a plotting field:
# (1) xfrm: encodes tile translations and rotations
# for tile corner points. (2) tl, tr, bl, br:
# tile corners, expressed in homogeneous
# coordinates.
-fill[plottingfield] ">if(
0<i#-2 && I#-1==[-1,0],
xfrm=eye(3);
xfrm[0]=I#-3[1];
xfrm[1]=I#-3[0];
xfrm[2]=x;
xfrm[3]=-I#-3[0];
xfrm[4]=I#-3[1];
xfrm[5]=y;
tl=mul(xfrm,[-"$th",-"$th"/2.0,1],1);
tr=mul(xfrm,[ "$th",-"$th"/2.0,1],1);
bl=mul(xfrm,[-"$th", "$th"/2.0,1],1);
br=mul(xfrm,[ "$th", "$th"/2.0,1],1);
polygon(#-1,5,
[tl[0],tl[1]],
[tr[0],tr[1]],
[br[0],br[1]],
[bl[0],bl[1]],
[tl[0],tl[1]],
1,[0,1]);
polygon(#-1,-5,
[tl[0],tl[1]],
[tr[0],tr[1]],
[br[0],br[1]],
[bl[0],bl[1]],
[tl[0],tl[1]],
1,0xffffffff,[1,1])
);I"
# Distort artwork
-warp[0,outline,plottingfield] [warper],1,2,2
-if {$fillholes==0}
-shared. 0
-round. 1
-rm.
-else
-remove_opacity.
-round. 1
-fi
-dilate_oct. 2
# Clean up z-axis data shifts
-cut[0] 0,255
-threshold[outline] 50%
-shared[plottingfield] 0
-fill. 'i#1>0?1:i#-1'
# Make height map for lighting.
# Distance from edges: proxy for
# tile height. Shape height with
# power function
-distance. 1
-normalize. 0,1
-pow. 0.25
-rm.
# Drop used data sets,
# Normalize for lighting
-remove[^0,-1]
-normalize[0,-1] 0,255
-if {s#-1>1}
-split_opacity[-1]
-fill. '[i<127?0:255]'
-move. 0
-fi
# Cheap Fingerpaint Lighting
# Derive shadow, hightlight, color
# Fixme: provisional coloring. Ought to
# be sampled from input image.
-blur. {$soft},1,1
+gradient. xy
-append[-2,-1] c
({cos(45*pi/180)}^{sin(45*pi/180)})
-resize. [-2],[-2],[-1],[-1],1
+mul[-2,-1]
-compose_channels. add
# Shadow
-cut. {ia},{iM}
-normalize. 0,1
-pow. 0.5
-blur. {$soft},1,1
-mul.. -1
-mul[-3,-2]
# Highlight
-compose_channels.. add
-cut.. {ia#-2},{iM#-2}
-normalize.. 0,1
-oneminus..
-pow.. 2
# Colorize. To do: sample color
# from input. For now, just mapping
# and colorspace twisting.
-blur.. {$soft},1,1
-normalize[-3] 0,1
-oneminus[-3]
-normalize[-3] 127,255
-map[-3] algae
# Provisional coloring
# Translate black/white of input into base° ± offset°
# colorspace rotations
-fill[-3] "begin(wv=vector3(1/sqrt(3)));
if(i(#-4,x,y,0,0),ang="$basec"+"$offsc",ang="$basec"-"$offsc");
rot(wv,ang)*I#-3"
# Composite
-mul[-3,-2]
-normalize. 0,255
-add[-2,-1]
-normalize. 0,255
-if {$fillholes==0}
-move[0] {$!}
-append[-2,-1] c
-fi
