forked from mirrors/linux
e88391f730
Zero-width Unicode code points are causing misalignment in vertically aligned content, disrupting the visual layout. Let's handle zero-width code points more intelligently. Double-width code points are stored in the screen grid followed by a white space code point to create the expected screen layout. When a double-width code point is followed by a zero-width code point in the console incoming bytestream (e.g., an emoji with a presentation selector) then we may replace the white space padding by that zero-width code point instead of dropping it. This maximize screen content information while preserving proper layout. If a zero-width code point is preceded by a single-width code point then the above trick is not possible and such zero-width code point must be dropped. VS16 (Variation Selector 16, U+FE0F) is special as it doubles the width of the preceding single-width code point. We handle that case by giving VS16 a width of 1 when that happens. Signed-off-by: Nicolas Pitre <npitre@baylibre.com> Link: https://lore.kernel.org/r/20250410011839.64418-4-nico@fluxnic.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
78 lines
1.5 KiB
C
78 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* consolemap.h
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*
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* Interface between console.c, selection.c and consolemap.c
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*/
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#ifndef __LINUX_CONSOLEMAP_H__
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#define __LINUX_CONSOLEMAP_H__
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enum translation_map {
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LAT1_MAP,
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GRAF_MAP,
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IBMPC_MAP,
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USER_MAP,
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FIRST_MAP = LAT1_MAP,
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LAST_MAP = USER_MAP,
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};
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#include <linux/types.h>
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struct vc_data;
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#ifdef CONFIG_CONSOLE_TRANSLATIONS
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u16 inverse_translate(const struct vc_data *conp, u16 glyph, bool use_unicode);
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unsigned short *set_translate(enum translation_map m, struct vc_data *vc);
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int conv_uni_to_pc(struct vc_data *conp, long ucs);
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u32 conv_8bit_to_uni(unsigned char c);
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int conv_uni_to_8bit(u32 uni);
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void console_map_init(void);
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bool ucs_is_double_width(uint32_t cp);
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static inline bool ucs_is_zero_width(uint32_t cp)
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{
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/* coming soon */
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return false;
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}
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#else
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static inline u16 inverse_translate(const struct vc_data *conp, u16 glyph,
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bool use_unicode)
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{
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return glyph;
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}
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static inline unsigned short *set_translate(enum translation_map m,
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struct vc_data *vc)
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{
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return NULL;
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}
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static inline int conv_uni_to_pc(struct vc_data *conp, long ucs)
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{
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return ucs > 0xff ? -1 : ucs;
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}
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static inline u32 conv_8bit_to_uni(unsigned char c)
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{
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return c;
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}
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static inline int conv_uni_to_8bit(u32 uni)
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{
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return uni & 0xff;
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}
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static inline void console_map_init(void) { }
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static inline bool ucs_is_double_width(uint32_t cp)
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{
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return false;
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}
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static inline bool ucs_is_zero_width(uint32_t cp)
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{
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return false;
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}
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#endif /* CONFIG_CONSOLE_TRANSLATIONS */
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#endif /* __LINUX_CONSOLEMAP_H__ */
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