Add a quick TIL about removing letterbox frames

src/_til/2024/2024-06-08-remove-letterboxing.md

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+---
+layout: til
+date: 2024-06-08 11:11:25 +0100
+title: Removing letterboxing from a video screenshot with ImageMagick
+summary: |
+  Using `-trim` will remove the black portions and leave you the unletterboxed image.
+tags:
+  - imagemagick
+---
+I was doing some work today with screenshots of a video that had [black "letterboxing" bars](https://en.wikipedia.org/wiki/Letterboxing_%28filming%29) around it.
+If you use `convert [input] -trim [output]`, you can remove this with ImageMagick.
+
+If the bars aren't pure black, you can add `-fuzz 10%` to pick up dark greys also.
+
+<style>
+  #examples {
+    display: grid;
+    grid-template-columns: 250px auto;
+    grid-gap: 1em;
+    align-items: center;
+  }
+
+  #examples pre {
+    margin: 0;
+  }
+</style>
+
+<div id="examples">
+  <img src="/images/2024/Windowboxed.jpg" alt="">
+  <p>
+    Original file, from <a href="https://en.wikipedia.org/wiki/File:Windowboxed.jpg">Wikimedia Commons</a>
+  </p>
+
+  <img src="/images/2024/Unboxed.jpg" alt="">
+  <pre><code>convert Windowboxed.jpg -trim Unboxed.jpg</code></pre>
+
+  <img src="/images/2024/Unboxed_10.jpg" alt="">
+  <pre><code>convert Windowboxed.jpg -fuzz 10% -trim Unboxed.jpg</code></pre>
+</div>