fix: multi-line text wrapping exception

[wang1212]

🤔 This is a ...

• New feature
• Bug fix
• Site / Document optimization
• TypeScript definition update
• Refactoring
• Performance improvement
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

#1833

💡 Background and solution

see #1876

When calculating the line break position, a more accurate result is obtained by adopting a strategy of character-by-character measurement cache combined with whole-text measurement. Among them, when the whole-text measurement strategy is used to approximate the optimal value character by character near the threshold, it is not considered that when a single character cannot be displayed, the character-by-character correction will cause the starting character position of each line to return to the beginning of the whole text, resulting in abnormal display after multiple lines of text are wrapped.

In order to deal with this edge case, the index of the last character of each line should be recorded, and when calculating the line break position of the current line, the starting character index of the current line should be used as the boundary condition.

Before

After

📝 Changelog

Language	Changelog
🇺🇸 English	fix: multi-line text wrapping exception
🇨🇳 Chinese	fix: 多行文本换行异常

☑️ Self Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

[petercat-assistant]

Walkthrough

This pull request addresses a bug related to multi-line text wrapping exceptions. The solution involves a more precise calculation of line break positions by using a character-by-character measurement cache combined with whole-text measurement. The fix ensures that the starting character index of each line is used as a boundary condition to handle edge cases where a single character cannot be displayed, preventing abnormal display after multiple lines of text are wrapped.

Changes

File	Summary
.changeset/popular-items-wave.md	Added a changeset for the patch fixing the multi-line text wrapping exception.
tests/demos/bugfix/textWordWrap.ts	Modified test cases to adjust wordWrapWidth and added new test cases to cover edge cases for text wrapping.
packages/g-lite/src/services/TextService.ts	Updated the text wrapping logic to record the index of the last character of each line and use it as a boundary condition for calculating line break positions.

[petercat-assistant]

Introduced prevLineLastCharIndex to keep track of the last character index of each line, which is crucial for handling edge cases in text wrapping.