Add Check Properties Of An Image With sips as a Mac TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
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+_1897 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -768,6 +768,7 @@ If you've learned something here, support my efforts writing daily TILs by
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 - [Capture Screenshot To Clipboard From CLI](mac/capture-screenshot-to-clipboard-from-cli.md)
 - [Check Network Quality Stats From The Command Line](mac/check-network-quality-stats-from-the-command-line.md)
+- [Check Properties Of An Image With `sips`](mac/check-properties-of-an-image-with-sips.md)
 - [Clean Up Item Layout In Finder Window](mac/clean-up-item-layout-in-finder-window.md)
 - [Clean Up Old Homebrew Files](mac/clean-up-old-homebrew-files.md)
 - [Control Which Monitor App Switcher Appears On](mac/control-which-monitor-app-switcher-appears-on.md)

mac/check-properties-of-an-image-with-sips.md

@@ -0,0 +1,49 @@
+# Check Properties Of An Image With `sips`
+
+I [used Figma to create a basic design for a t-shirt
+screenprinting](https://bsky.app/profile/jbranchaud.bsky.social/post/3mz43v6asns2f).
+Before I sent the image asset off to the printer, I needed to verify a couple
+properties of the image where right.
+
+My first thought was that there is probably a way to do this with `ffmpeg`, but
+I intentionally asked Claude in a non-leading way how to do this. It surfaced a
+Mac-specific utility I'd never heard of -- `sips` (_Scriptable Image Processing
+System_).
+
+Sometimes it is hard to tell if an image exported correctly with transparent
+background (alpha channel). Part of how I was able to verify that was to point
+`sips` at the PNG file and ask if it has an alpha channel. The `-g` flag (short
+for _get property_) is the way to output a property like this.
+
+```bash
+❯ sips -g hasAlpha ~/Downloads/Untitled/orange-shirt-print-front.png
+/Users/lastword/Downloads/Untitled/orange-shirt-print-front.png
+  hasAlpha: yes
+```
+
+I then wanted to check that the dimensions of the image were right. I had
+carefully sized the canvas in Figma to correspond to specs required by the
+printer. Similar to above, I can use `-g` to grab the `pixelWidth` and
+`pixelHeight` properties of the image.
+
+Unfortunately the pixel dimensions of the exported PNG were not what I was
+expecting.
+
+```bash
+❯ sips -g pixelWidth -g pixelHeight ~/Downloads/Untitled/orange-shirt-print-front.png
+/Users/lastword/Downloads/Untitled/orange-shirt-print-front.png
+  pixelWidth: 1152
+  pixelHeight: 1536
+```
+
+I then found some additional export settings in Figma and tried again. Nailed
+it.
+
+```bash
+❯ sips -g pixelWidth -g pixelHeight ~/Downloads/Marty\ Supreme\ —\ 12\ ×\ 16\ in\ print.png
+/Users/lastword/Downloads/Marty Supreme — 12 × 16 in print.png
+  pixelWidth: 3600
+  pixelHeight: 4800
+```
+
+See `man sips` for more details.