Seamless blending

[druzhynin-oleksii]

larger_img.png

fit_smaller.png

    # magick -verbose \
    #  larger_img.png \
    #  \( fit_smaller.png +write mpr:INP \) \
    #  \( mpr:INP -alpha extract \
    #    -morphology erode disk:3 \
    #    -alpha off \
    #  \) \
    #  -compose seamless_blend -composite \
    #  target.png

    target_img = wand.image.Image.from_array(larger_rgba, channel_map='RGBA')

    #  \( fit_smaller.png +write mpr:INP \) \
    src_img = wand.image.Image.from_array(fit_smaller_rgba, channel_map='RGBA')
    src_img_mask = src_img.clone()

    # ( mpr:INP -alpha extract -morphology erode disk:3 -alpha off )
    src_img_mask.alpha_channel = 'extract'
    src_img_mask.morphology(method='erode', kernel='disk:3')
    src_img_mask.alpha_channel = 'off'

    # -compose seamless_blend -composite
    src_img.composite(src_img_mask, operator='copy_alpha')
    target_img.composite(src_img, operator='seamless_blend', arguments='400x0.00002+100')

see results: ImageMagick/ImageMagick#6578

[emcconville]

This matches the CLI without all the unnecessary steps.

from wand.image import Image

with Image(filename='larger_img.png') as img:
  with Image(filename='fit_smaller.png') as subject:
    subject.morphology(method='erode', kernel='disk:3', channel='alpha')
    img.composite(subject, operator='seamless_blend')
  img.save(filename='target.png')

[druzhynin-oleksii]

thanks, but how to skip erode if the radius is too small?

from wand.image import Image

with Image(filename='larger_img.png') as img:
  with Image(filename='fit_smaller.png') as subject:
    if disk_kernel > 1:
        subject.morphology(method='erode', kernel=f'disk:{disk_kernel}', channel='alpha')
    else:
        ??? # all the non-transparent pixels as a mask
    img.composite(subject, operator='seamless_blend')
  img.save(filename='target.png')

is subject.alpha_channel = 'copy'enough to use non-transparent pixels of the subject as a mask?

[emcconville]

Shouldn't need to do anything for the else statement. The alpha channel is the mask, so all the non-transparent pixels would be used by the blend.