| name | image-processing |
| description | Use this when converting, resizing, cropping, stitching, or annotating images;
building a filmstrip, contact sheet, or grid; correcting orientation or color;
or applying common ImageMagick-style effects with SLICC's `convert` / `magick`
shell command.
|
| allowed-tools | bash |
Image processing with convert
SLICC's local ImageMagick WASM command handles common image transforms, multi-image composition, and labels without network access. magick is an alias for convert.
Compose filmstrips and grids
Join images horizontally with +append or vertically with -append:
convert f00.jpg f01.jpg f02.jpg f03.jpg +append /tmp/filmstrip.jpg
convert top.png middle.png bottom.png -append /tmp/column.png
Build grids with escaped parenthesized groups. Each group produces one intermediate image:
convert \( f00.jpg f01.jpg f02.jpg f03.jpg +append \) \
\( f04.jpg f05.jpg f06.jpg f07.jpg +append \) \
-append /tmp/grid.jpg
Transform images
Operations run from left to right on the preceding image or group:
convert photo.jpg -auto-orient -thumbnail '320x320>' -strip thumb.jpg
convert input.png -gravity center -crop 800x600+0+0 output.png
convert input.png -background white -gravity center -extent 1200x630 output.png
convert input.png -colorspace Gray -normalize -sharpen 0x1 output.png
Common operations:
- Geometry:
-resize, -thumbnail, -crop, -extent, -rotate
- Orientation:
-auto-orient, -flip, -flop
- Cleanup:
-strip, -trim, -auto-gamma, -auto-level, -normalize
- Color/alpha:
-background, -alpha, -colorspace, -transparent, -negate
- Effects:
-blur R[xS], -sharpen R[xS]
- Output:
-quality 0-100
Resize geometry accepts ImageMagick modifiers such as %, !, ^, >, and <. Quote geometry containing shell metacharacters.
Add labels
Configure the drawing state before -annotate:
convert frame.jpg -gravity south -fill white -undercolor '#000000aa' \
-pointsize 24 -annotate +0+10 'Frame 07 — 00:03.5' labeled.jpg
Annotation uses the bundled Adobe Clean font; custom -font selection is not supported yet.
Use -gravity with northwest, north, northeast, west, center, east, southwest, south, or southeast. Quote label text and colors containing #.
Verify and inspect
file /tmp/grid.jpg
open --view --size high /tmp/grid.jpg
convert --help
Keep the output path last. Multiple inputs must be reduced with +append or -append; escape group parentheses as \( and \) so the shell passes them to convert.
