| name | imagemagick-expert |
| description | ImageMagick patterns for video pipeline work — title cards, contact sheets, thumbnails, text annotation, HEIC conversion, letterboxing, and color overlays. |
ImageMagick Expert
Mental Model
magick [input | -size WxH xc:color] → [operations in order] → output
- Operations are applied left to right and modify the current image state
-gravity sets the anchor for all subsequent -annotate, -extent, and -splice calls — reset it explicitly when switching-background affects -extent, -splice, and canvas creation- Settings like
-font, -fill, -stroke, -pointsize persist until changed — always reset -stroke none after stroking
Quick Reference
| I need to... | Use |
|---|
| Title card from scratch (black canvas + text) | → references/text-and-cards.md |
| Text on a photo with readable outline | → references/text-and-cards.md (stroke trick) |
| Multi-line text card with different sizes | → references/text-and-cards.md |
| Letterbox a photo to 1920×1080 | → references/transforms.md |
| Crop-fill a photo (no black bars) | → references/transforms.md |
| Dark scrim overlay for text contrast | → references/transforms.md |
| Numbered thumbnail for contact sheet | → references/contact-sheets.md |
| Grid of photo thumbnails | → references/contact-sheets.md |
| Grid of clip thumbnails with duration labels | → references/contact-sheets.md |
| Convert HEIC to JPEG | → references/transforms.md |
Must-Know Gotchas
| Issue | Fix |
|---|
| EXIF rotation ignored | Always add -auto-orient before any resize |
| Stroke bleeds into next text | Reset with -stroke none after every stroke pass |
-splice adds to wrong side | It adds to the side set by -gravity (South = bottom) |
convert vs magick | Use magick (v7+). convert still works but is legacy |
| Font not found | Use full TTF path, not font name. Run magick -list font to verify |
-gravity affects -extent | Set to Center before -extent for centered letterbox |
| HEIC support missing | brew install libheif for magick, or use sips as fallback |
macOS Font Paths
/System/Library/Fonts/Supplemental/Georgia.ttf
/System/Library/Fonts/HelveticaNeue.ttc
/System/Library/Library/Fonts/Supplemental/Arial.ttf
Use full paths in scripts. SF Pro (system UI font) is not directly accessible to ImageMagick.
magick -list font — shows all fonts ImageMagick can find by name (not always reliable cross-machine).
Temp File Pattern
For multi-step batch processing:
tmpdir=$(mktemp -d)
trap "rm -rf $tmpdir" EXIT
for photo in "${photos[@]}"; do
magick "$photo" [ops] "${tmpdir}/labeled_$(printf '%03d' $idx).jpg"
done
magick montage "${tmpdir}"/labeled_*.jpg [montage opts] output.jpg
References
references/text-and-cards.md — title cards, annotation gravity, multi-line, stroke outline trickreferences/contact-sheets.md — labeled thumbnails, magick montage, clip sheetsreferences/transforms.md — letterbox, crop, HEIC, dark overlays, color operations
