Commit 547f57b8 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Greg Kroah-Hartman
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vt: pad double-width code points with a zero-white-space 



In the Unicode screen buffer, we follow double-width code points with a
space to maintain proper column alignment. This, however, creates
semantic problems when e.g. using cut and paste or selection.

Let's use a better code point for the column padding's purpose i.e. a
zero-white-space rather than a full space.

Signed-off-by: default avatarNicolas Pitre <npitre@baylibre.com>
Link: https://lore.kernel.org/r/20250410011839.64418-12-nico@fluxnic.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c7cb5b07

drivers/tty/vt/vt.c

+8 −3
Original line number Diff line number Diff line
@@ -2937,12 +2937,13 @@ static int vc_con_write_normal(struct vc_data *vc, int tc, int c, 
			width = 2;

		} else if (ucs_is_zero_width(c)) {

			prev_c = vc_uniscr_getc(vc, -1);

			if (prev_c == ' ' &&

			if (prev_c == 0x200B &&

			    ucs_is_double_width(vc_uniscr_getc(vc, -2))) {

				/*

				 * Let's merge this zero-width code point with

				 * the preceding double-width code point by

				 * replacing the existing whitespace padding.

				 * replacing the existing zero-white-space

				 * padding.

				 */

				vc_con_rewind(vc);

			} else if (c == 0xfe0f && prev_c != 0) {
@@ -3040,7 +3041,11 @@ static int vc_con_write_normal(struct vc_data *vc, int tc, int c, 
		tc = conv_uni_to_pc(vc, ' ');

		if (tc < 0)

			tc = ' ';

		next_c = ' ';

		/*

		 * Store a zero-white-space in the Unicode screen given that

		 * the previous code point is semantically double-width.

		 */

		next_c = 0x200B;

	}



out: