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Add better support for CJK wrapping. #8838

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Add better support for CJK wrapping. #8838

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6ef3ef0
Added helper functions for Chinese punctuations.
cyx2015s Jul 27, 2025
4f0876e
CalcWordWrapPosition: Added basic Chinese word wrap function.
cyx2015s Jul 27, 2025
f01e445
Misc: fix typo in comments; align code.
cyx2015s Jul 27, 2025
5d7bb10
Use the name head/tail prohibited and add more symbos.
cyx2015s Jul 27, 2025
fdecc2f
fix wrap behavior when a English letter is directly after a CJK chara…
cyx2015s Jul 27, 2025
c75a83b
added ImCharIsLineBreakableW to check whether this char can break any…
cyx2015s Jul 27, 2025
dddfe47
make more characters breakable
cyx2015s Jul 27, 2025
558c56a
[Buggy] Total rewrite. Don't use now.
cyx2015s Jul 29, 2025
95f30de
Minor tweaks
cyx2015s Jul 30, 2025
7dfcaa5
Removed a lot of redundant logic
cyx2015s Jul 30, 2025
e3ab512
Fix wrapping behavior when there are large chunk of spaces
cyx2015s Jul 30, 2025
89cef0e
Fixed a error due to type conversion.
cyx2015s Jul 30, 2025
3e1674b
Removed debug assert
cyx2015s Jul 30, 2025
326b00d
Added ! to breakables
cyx2015s Jul 30, 2025
06ea14b
Better number wrapping behavior
cyx2015s Jul 30, 2025
4237b6d
Just don't wrap when some thing is surrounded by numbers.
cyx2015s Jul 30, 2025
a1ee580
add ':", fix number detection
cyx2015s Aug 2, 2025
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added ImCharIsLineBreakableW to check whether this char can break any… 
…where.
  • Loading branch information
@cyx2015s
cyx2015s committed Jul 27, 2025
commit c75a83bfd20014027779a7cca9a9cda7013057e5
22 changes: 11 additions & 11 deletions imgui_draw.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5381,8 +5381,8 @@ const char* ImFont::CalcWordWrapPosition(float size, const char* text, const cha
const char* word_end = text;
const char* prev_word_end = NULL;
bool inside_word = true;
bool last_char_is_cjk = false;
bool last_char_is_init = false;
bool last_char_is_line_breakable = false;
bool last_char_is_tail_prohibited = false;

const char* s = text;
IM_ASSERT(text_end != NULL);
Expand Down Expand Up @@ -5426,8 +5426,8 @@ const char* ImFont::CalcWordWrapPosition(float size, const char* text, const cha
}
blank_width += char_width;
inside_word = false;
last_char_is_cjk = false;
last_char_is_init = false;
last_char_is_line_breakable = false;
last_char_is_tail_prohibited = false;
}
else if (ImCharIsHeadProhibitedW(c))
{
Expand All @@ -5438,8 +5438,8 @@ const char* ImFont::CalcWordWrapPosition(float size, const char* text, const cha
inside_word = false;
// Wrap after this punctuation.
prev_word_end = word_end = next_s;
last_char_is_cjk = false;
last_char_is_init = false;
last_char_is_line_breakable = false;
last_char_is_tail_prohibited = false;
}
else
{
Expand All @@ -5451,26 +5451,26 @@ const char* ImFont::CalcWordWrapPosition(float size, const char* text, const cha
prev_word_end = word_end;
word_end = next_s;
}
else if (0x3003 <= c && c <= 0xFFFF)
else if (ImCharIsLineBreakableW(c))
{
// CJK characters are not separated by spaces, so we treat them as a single word.
// This is a very simple heuristic, but it works for most cases.
line_width += word_width + blank_width;
word_width = blank_width = 0.0f;
inside_word = true;
if ((!last_char_is_init && 0x3003 <= c && c <= 0xFFFF) || !last_char_is_cjk)
if ((!last_char_is_tail_prohibited && ImCharIsLineBreakableW(c)) || !last_char_is_line_breakable)
prev_word_end = s;
}
else if (!ImCharIsHeadProhibitedW(c) && last_char_is_cjk && !last_char_is_init)
else if (!ImCharIsHeadProhibitedW(c) && last_char_is_line_breakable && !last_char_is_tail_prohibited)
{
// Not a cjk character, not a head prohibited punctuation, previous char is not tail prohibited.
line_width += word_width + blank_width;
word_width = blank_width = 0.0f;
prev_word_end = s;
inside_word = true;
}
last_char_is_cjk = 0x3003 <= c && c <= 0xFFFF;
last_char_is_init = ImCharIsTailProhibitedW(c);
last_char_is_line_breakable = ImCharIsLineBreakableW(c);
last_char_is_tail_prohibited = ImCharIsTailProhibitedW(c);
word_width += char_width;
if (inside_word)
{
Expand Down
1 change: 1 addition & 0 deletions imgui_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -409,6 +409,7 @@ inline bool ImCharIsHeadProhibitedW(unsigned int c) { return c ==
// Only include characters can be typed within 1 or 2 hits on a standard keyboard.
// List: （【《「『
inline bool ImCharIsTailProhibitedW(unsigned int c) { return c == 0xff08 || c == 0x3010 || c == 0x300a || c == 0x300c || c == 0x300e; }
inline bool ImCharIsLineBreakableW(unsigned int c) { return (c >= 0x4E00 && c <= 0x9FFF) || (c >= 0x3400 && c <= 0x4DBF) || (c >= 0x20000 && c <= 0x2EBEF) || (c >= 0x3040 && c <= 0x30FF) || (c >= 0xAC00 && c <= 0xD7AF); }
inline bool ImCharIsXdigitA(char c) { return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f'); }
IM_MSVC_RUNTIME_CHECKS_RESTORE

Expand Down