fix(textinput): use display width for cursor position with CJK characters#920
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amosbird wants to merge 1 commit intocharmbracelet:mainfrom
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fix(textinput): use display width for cursor position with CJK characters#920amosbird wants to merge 1 commit intocharmbracelet:mainfrom
amosbird wants to merge 1 commit intocharmbracelet:mainfrom
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…ters Cursor() used m.Position() (rune index) to compute the X offset, which is incorrect for wide characters like CJK that occupy 2 terminal columns per rune. Replace it with uniseg.StringWidth to compute the actual display width of the visible text before the cursor.
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Summary
Cursor()usedm.Position()(rune index) to compute the X offset. This is incorrect for wide characters (e.g. CJK) that occupy 2 terminal columns per rune, causing the real cursor to be placed to the left of where it should be.Fix: replace
m.Position()withuniseg.StringWidth(string(m.value[m.offset:m.pos]))to compute the actual display width of the visible text before the cursor.Test plan
TestCursorPositionWithCJKCharacters— pure CJK inputTestCursorPositionWithMixedASCIIAndCJK— mixed ASCII + CJKTestCursorPositionCJKWithOffset— narrow width forcing scroll, cursor stays within bounds