[READ-ONLY] Mirror of https://github.com/bombshell-dev/tty. Platform independent 2D layout engine for terminal applications based on Clay
Merge pull request #14 from thefrontside/decouple-altbuffer-clear
Decouple alternate buffer switching from clearing
authored by
Charles Lowell
and committed by
GitHub
(Apr 17, 2026, 12:25 PM -0500)
a6b1ee1e
5372af80
+24
-8
+4
-2
settings.ts
+4
-2
settings.ts
+14
-6
termcodes.ts
+14
-6
termcodes.ts
···
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}
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/**
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* Switch to the alternate screen buffer (xterm private mode 1049).
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* Switch to the alternate screen buffer.
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*
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* Saves the cursor and switches to a clean alternate screen. Use
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* {@link MAINSCREEN} to switch back.
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* Saves the cursor and switches to the alternate screen. When `clear` is
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* `true` (the default), the alternate buffer is cleared on entry. When
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* `false`, the existing contents are preserved.
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*
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* Use {@link MAINSCREEN} to switch back.
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*
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* @see {@link https://invisible-island.net/xterm/ctlseqs/ctlseqs.html | xterm control sequences}
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*/
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export function ALTSCREEN(): Uint8Array {
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return CSI("?1049h");
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export function ALTSCREEN(options?: { clear?: boolean }): Uint8Array {
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let { clear = true } = options ?? {};
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if (clear) {
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return CSI("?1049h");
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} else {
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return CSI("?47h");
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}
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}
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/**
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* Switch back to the main screen buffer (xterm private mode 1049).
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* Switch back to the main screen buffer.
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*
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* Restores the cursor and returns to the main screen with scrollback intact.
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*
+6
test/settings.test.ts
+6
test/settings.test.ts
···
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expect(str(s.apply)).toBe("\x1b[?1049h");
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expect(str(s.revert)).toBe("\x1b[?1049l");
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});
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it("uses mode 47 when clear is false", () => {
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let s = alternateBuffer({ clear: false });
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expect(str(s.apply)).toBe("\x1b[?47h");
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expect(str(s.revert)).toBe("\x1b[?1049l");
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});
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});
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describe("cursor", () => {