feat: add dandelion example, remove snow globe

example/assets/dandelion/tools/build-atlas.sh

@@ -0,0 +1,112 @@
+#!/bin/sh
+# Builds dandelion-atlas.jpg from the source photo. Needs ImageMagick 7 and Xcode
+# (Vision, for the foreground mask). Run from this directory with the photo as $1:
+#
+#   curl -A 'rn-effects-example/1.0' -o source.jpg "<thumb.wikimedia.org url from the Commons API, iiurlwidth=3840>"
+#   sh build-atlas.sh source.jpg
+#
+# The committed atlas was built from the 3840x5120 thumb; the output is
+# byte-identical on a rebuild from that source.
+#
+# Photo: "Taraxacum seedhead Paslieres 2013-05-09 n01.jpg", Marie-Lan Nguyen,
+# CC BY 2.5, https://commons.wikimedia.org/wiki/File:Taraxacum_seedhead_Paslieres_2013-05-09_n01.jpg
+#
+# Output is one image, three panels of PW x PH side by side:
+#   left    the photo, scaled to PW wide and extended upward with smeared bokeh so
+#           the seeds have sky to fly into on a phone-shaped canvas
+#   middle  the same with the seed head painted out (normalised-convolution fill of
+#           the surrounding bokeh), stem kept, a small receptacle knob at the centre
+#   right   data: R = soft head mask, G = hair matte (white pappus pixels), B = 0
+set -eu
+SRC=${1:?source photo}
+PW=1000; PH=2174
+CX=503; CY=1321; R=395          # head centre + radius on the canvas, px (measured from the mask)
+STEM_X0=455; STEM_X1=545        # stem column on the canvas
+T=$(mktemp -d)
+
+# 1. Scale, then extend upward: the photo is 3:4 and the canvas is phone-shaped.
+#    The extension is the photo's top rows stretched into vertical streaks (more
+#    out-of-focus grass), and the photo's first FADE rows cross-fade into it so
+#    the join has no line. The head starts ~110 rows in, so FADE stays under that.
+FADE=90
+magick "$SRC" -resize ${PW}x "$T/photo.png"
+PHOTO_H=$(identify -format %h "$T/photo.png")
+EXT=$((PH - PHOTO_H))
+magick "$T/photo.png" -crop ${PW}x12+0+0 +repage -resize ${PW}x$((EXT + FADE))! -blur 0x20 "$T/ext.png"
+magick -size ${PW}x${FADE} gradient:black-white "$T/fade.png"
+magick "$T/photo.png" -crop ${PW}x${FADE}+0+0 +repage "$T/fade.png" -alpha off -compose CopyOpacity -composite "$T/photo_top_a.png"
+magick "$T/ext.png" "$T/photo_top_a.png" -geometry +0+${EXT} -compose Over -composite "$T/ext.png"
+magick "$T/photo.png" -crop ${PW}x$((PHOTO_H - FADE))+0+${FADE} +repage "$T/photo_rest.png"
+magick "$T/ext.png" "$T/photo_rest.png" -append +repage "$T/canvas.png"
+
+# 2. Foreground mask (Vision), on the canvas.
+[ -x ./liftmask ] || swiftc -O liftmask.swift -o liftmask
+./liftmask "$T/photo.png" "$T/mask_photo.png"
+magick -size ${PW}x${EXT} xc:black \( "$T/mask_photo.png" -colorspace gray \) -append +repage -depth 8 "$T/vision.png"
+
+# 3. Head disc, stem, hair matte.
+magick -size ${PW}x${PH} xc:black -fill white -draw "circle $CX,$CY $((CX + R)),$CY" -blur 0x6 "$T/disc.png"
+magick -size ${PW}x${PH} xc:black -fill white -draw "rectangle $STEM_X0,$((CY + R * 86 / 100)) $STEM_X1,$PH" "$T/stemcol.png"
+magick "$T/vision.png" "$T/stemcol.png" -compose Multiply -composite "$T/stem.png"
+magick "$T/disc.png" "$T/vision.png" -compose Multiply -composite \
+  \( "$T/stem.png" -negate \) -compose Multiply -composite "$T/head.png"
+magick "$T/canvas.png" -colorspace HSL -channel G -separate +channel -negate -level 45%,85% "$T/satkey.png"
+magick "$T/canvas.png" -colorspace gray -level 40%,80% "$T/lumkey.png"
+magick "$T/satkey.png" "$T/lumkey.png" -compose Multiply -composite "$T/head.png" -compose Multiply -composite "$T/hair.png"
+
+# 4. Bald panel: paint the head out. A push-pull inpaint — repeated normalised
+#    convolutions, blur(img * known) / blur(known), each pass filling the pixels
+#    the previous one reached — pulls the surrounding bokeh inward with its
+#    gradient instead of averaging it into one flat disc. Then the stem is
+#    extended up to the centre (it was hidden behind the seeds) and a small
+#    receptacle sits on top. A bare receptacle is a pale pitted dome, so it is
+#    the photo's own centre with the hairs blurred away and shrunk down: the
+#    achene bases become the pits. Pasting the centre in at full size left a
+#    dandelion in miniature on the stem.
+# The fill reaches well past the disc and feathers out over ~50 px: the fringe
+# hairs run ~40 px beyond R, and a fill that stopped short of them pulled
+# their white into the estimate; a hard-edged fill, however far out, read as
+# a smooth pale disc set into the mottled bokeh.
+magick -size ${PW}x${PH} xc:black -fill white -draw "circle $CX,$CY $((CX + R + 70)),$CY" -blur 0x25 \
+  \( "$T/stem.png" -negate \) -compose Multiply -composite -alpha off "$T/fill.png"
+# Masks must be plain grayscale: a stray alpha channel turns Multiply into a blend.
+magick "$T/fill.png" -negate -threshold 50% -alpha off "$T/known.png"
+cp "$T/canvas.png" "$T/work.png"
+for SIGMA in 6 10 16 26 40 64 100; do
+  magick "$T/work.png" "$T/known.png" -compose Multiply -composite -blur 0x$SIGMA "$T/num.png"
+  magick "$T/known.png" -blur 0x$SIGMA "$T/den.png"
+  magick "$T/num.png" "$T/den.png" -compose Divide_Src -composite "$T/est.png"
+  # Pixels the blur reached with some confidence become known this pass.
+  magick "$T/den.png" -threshold 4% -alpha off "$T/reached.png"
+  magick "$T/reached.png" \( "$T/known.png" -negate \) -compose Multiply -composite -alpha off "$T/newly.png"
+  magick "$T/est.png" "$T/newly.png" -alpha off -compose CopyOpacity -composite "$T/est_a.png"
+  magick "$T/work.png" "$T/est_a.png" -compose Over -composite "$T/work.png"
+  magick "$T/known.png" "$T/newly.png" -compose Plus -composite -alpha off "$T/known.png"
+done
+magick "$T/work.png" -blur 0x3 "$T/fill.png" -alpha off -compose CopyOpacity -composite "$T/infill_a.png"
+magick "$T/canvas.png" "$T/infill_a.png" -compose Over -composite "$T/bald.png"
+# Stem up to the receptacle: the visible stem's top rows stretched upward,
+# feathered at the sides so the strip blends into the fill.
+STEM_TOP=$((CY + R * 86 / 100))
+SEG_H=$((STEM_TOP - CY + 12))
+magick "$T/canvas.png" -crop $((STEM_X1 - STEM_X0))x40+${STEM_X0}+${STEM_TOP} +repage -resize $((STEM_X1 - STEM_X0))x${SEG_H}! "$T/stemseg.png"
+magick "$T/stem.png" -crop $((STEM_X1 - STEM_X0))x1+${STEM_X0}+$((STEM_TOP + 20)) +repage -blur 0x3 -resize $((STEM_X1 - STEM_X0))x${SEG_H}! "$T/stemseg_m.png"
+magick "$T/stemseg.png" "$T/stemseg_m.png" -alpha off -compose CopyOpacity -composite "$T/stemseg_a.png"
+magick "$T/bald.png" "$T/stemseg_a.png" -geometry +${STEM_X0}+$((CY - 12)) -compose Over -composite "$T/bald.png"
+KR=$((R / 7))
+SRC_R=$((R / 3))
+magick "$T/canvas.png" -crop $((2 * SRC_R))x$((2 * SRC_R))+$((CX - SRC_R))+$((CY - SRC_R)) +repage \
+  -blur 0x6 -resize $((2 * KR))x$((2 * KR))! -modulate 118,45,100 "$T/knob.png"
+# Dome shading: bright at the crown, falling off toward the rim.
+magick -size $((2 * KR))x$((2 * KR)) radial-gradient:white-gray55 "$T/dome.png"
+magick "$T/knob.png" "$T/dome.png" -compose Multiply -composite "$T/knob.png"
+magick -size $((2 * KR))x$((2 * KR)) xc:black -fill white -draw "circle $KR,$KR $((2 * KR - 2)),$KR" -blur 0x2 "$T/knobmask.png"
+magick "$T/knob.png" "$T/knobmask.png" -alpha off -compose CopyOpacity -composite "$T/knob_a.png"
+magick "$T/bald.png" "$T/knob_a.png" -geometry +$((CX - KR))+$((CY - KR)) -compose Over -composite "$T/bald.png"
+
+# 5. Data panel and atlas.
+magick "$T/head.png" "$T/hair.png" -size ${PW}x${PH} xc:black -channel RGB -combine "$T/data.png"
+magick "$T/canvas.png" "$T/bald.png" "$T/data.png" +append -sampling-factor 1x1 -quality 90 ../dandelion-atlas.jpg
+cp "$T/canvas.png" "$T/bald.png" "$T/data.png" "${ATLAS_DEBUG_DIR:-$T}/" 2>/dev/null || true
+identify ../dandelion-atlas.jpg
+ls -la ../dandelion-atlas.jpg

example/assets/dandelion/tools/liftmask.swift

@@ -0,0 +1,23 @@
+// swift liftmask.swift in.jpg mask.png
+// Foreground-instance mask (the same model iOS "lift subject" uses), soft, full-res.
+import Foundation
+import Vision
+import CoreImage
+import AppKit
+
+let args = CommandLine.arguments
+guard args.count == 3 else { fputs("usage: liftmask in out.png\n", stderr); exit(1) }
+let url = URL(fileURLWithPath: args[1])
+guard let ci = CIImage(contentsOf: url) else { fputs("cannot read input\n", stderr); exit(1) }
+let handler = VNImageRequestHandler(ciImage: ci, options: [:])
+let req = VNGenerateForegroundInstanceMaskRequest()
+try handler.perform([req])
+guard let obs = req.results?.first else { fputs("no foreground found\n", stderr); exit(2) }
+let pb = try obs.generateScaledMaskForImage(forInstances: obs.allInstances, from: handler)
+let maskCI = CIImage(cvPixelBuffer: pb)
+let ctx = CIContext()
+guard let cg = ctx.createCGImage(maskCI, from: maskCI.extent) else { exit(3) }
+let rep = NSBitmapImageRep(cgImage: cg)
+guard let png = rep.representation(using: .png, properties: [:]) else { exit(4) }
+try png.write(to: URL(fileURLWithPath: args[2]))
+print("mask \(cg.width)x\(cg.height)")

example/src/App.tsx

@@ -38,9 +38,9 @@ import BirthdayCandleScreen from './screens/BirthdayCandleScreen';
 import ParticleDispersionScreen from './screens/ParticleDispersionScreen';
 import FoamLabScreen from './screens/FoamLabScreen';
 import VoiceDeleteScreen from './screens/VoiceDeleteScreen';
-import SnowGlobeScreen from './screens/SnowGlobeScreen';
 import Magic8BallScreen from './screens/Magic8BallScreen';
 import CigaretteScreen from './screens/CigaretteScreen';
+import DandelionScreen from './screens/DandelionScreen';
 import type { RootStackParamList } from './types';
 
 const Stack = createNativeStackNavigator<RootStackParamList>();
@@ -137,9 +137,9 @@ export default function App() {
             name="VoiceDeleteExample"
             component={VoiceDeleteScreen}
           />
-          <Stack.Screen name="SnowGlobeExample" component={SnowGlobeScreen} />
           <Stack.Screen name="Magic8BallExample" component={Magic8BallScreen} />
           <Stack.Screen name="CigaretteExample" component={CigaretteScreen} />
+          <Stack.Screen name="DandelionExample" component={DandelionScreen} />
         </Stack.Navigator>
       </NavigationContainer>
     </GestureHandlerRootView>