terminal: decaln

website/app/vt/decaln/page.mdx

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+import VTSequence from "@/components/VTSequence";
+
+# Screen Alignment Test (DECALN)
+
+<VTSequence sequence={["ESC", "#", "8"]} />
+
+Reset margins, move cursor to the top left, and fill the screen with `E`.
+
+Reset the top, bottom, left, and right margins and unset [origin mode](#TODO).
+The cursor is moved to the top-left corner of the screen.
+
+All stylistic SGR attributes are unset, such as bold, blink, etc.
+SGR foreground and background colors are preserved.
+The [protected attribute](#TODO) is not unset.
+
+The entire screen is filled with the character `E`. The letter `E` ignores
+the current SGR settings and is written with no styling.
+
+## Validation
+
+### DECALN V-1: Simple Usage
+
+```bash
+printf "\033#8"
+```
+
+```
+|EEEEEEEE|
+|EEEEEEEE|
+|EEEEEEEE|
+```
+
+### DECALN V-2: Reset Margins
+
+```bash
+printf "\033[2;3r" # scroll region top/bottom
+printf "\033#8"
+printf "\033[T"
+```
+
+```
+|c_______|
+|EEEEEEEE|
+|EEEEEEEE|
+```