Imagemagick image warp

imageMagickWarp.bsh

#### Reference commands to do uv mapping with magick

# create a grad by making 'n' vertical bands of colors and blurring
echo "P2 4 1 255\n 137 195 125 255" | convert -   -depth 16 -scale 151x50\! -blur 0x6 -resize 4096x1436\! +matte   displace_map.tif

# use the grad to warp image
# note use of fx expression to make it resolution independent
inputImage=test.jpg
outputImage=testWarped.jpg
magick ${inputImage} -depth 16 displace_map.tif -virtual-pixel Gray -compose Displace -set option:compose:args '%[fx:w*.0855]x%[fx:0]' -composite -crop '%[fx:h*2]x%[fx:h]+%[fx:w*0.146]+%[fx:0]' ${inputImage}


#################################
 # alternate means to make a arbitrary grad but it's a pain to setup and is not quite as directly controllable
 # Use this script to generate polynomial coefficients
crv=$(./im_fx_curves  -c -p 0,50 50,100 100,51)
# Imagemagick command to apply them
magick -size 512x512 -define gradient:direction=east gradient:black-white -function Polynomial "${crv}" poo.png
 
 #################################
 ## Diplacement encodes how far to move the image pixel from its current location. Below 127 is left and above 127 is right
 
 magick {image} {displacement_map} \
            -compose Displace   -define compose:args={X}x{Y} \
            -composite   {result+}

    magick {image} {displacement_map} \
            -compose Displace   -set option:compose:args {X}x{Y} \
            -composite   {result+}

    magick composite {displacement_map} {image} \
              -displace {X}x{Y}    {result+}

## Distortion maps encode an absolute destination location for the pixel
##
magick koala.gif  map_compress.gif map_compress_y.gif \
          -set option:compose:args '%[fx:w/2]x%[fx:h/2]' \
          -compose Distort  -composite \
          distort_compose_set.gif