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@@ -76,6 +76,17 @@ and everything after it silently disappears, which looks like a layout or
buffer-overflow bug and is neither. `set_clip()` clamps to the buffer bounds
before converting.
+### Verifying a frame without a screenshot
+
+ MUX_DUMP=/tmp/frame.ppm ./colitur-mu # writes one frame, then exits
+ convert /tmp/frame.ppm /tmp/frame.png
+
+This reads back the off-screen PIXMAP, not the window. A window's contents
+are not retained while it is obscured or sitting on an unfocused tag, so
+`import`/`xwd` against one can return solid black while the program is
+drawing perfectly -- which cost real time to work out once. A pixmap is
+always there.
+
### Which to use
`colitur-x` renders; `colitur-mu` renders and lets you change the invocation.