Wrong cursor positioning with complex scrips

[santhoshtr]

Paste the following text to brackets, and see where the cursor is placed

സന്തോഷ്

Cursor is supposed to place at end of the word, but in brackets it is after 4 or 5 character width.

Happens with all non-latin complex scripts

[peterflynn]

Reproduces in vanilla CodeMirror too

[santhoshtr]

It seems bracket is placing the cursor based on the character count. The word സന്തോഷ് has 7 unicode characters. But the visual width is not 7 X character width. For complex scripts, the characters combine and form ligatures. Browsers can do this natively, overriding it using user level logic is bad idea.

[njx]

Doesn't seem to repro in CM in FF, so this might be a Chrome-only CM issue.

[njx]

To me to file against CM

[santhoshtr]

What is CM?

[peterflynn]

@santhoshtr CM is referring to CodeMirror, the code-editor UI widget that Brackets uses.

[santhoshtr]

Ok, reported there codemirror/codemirror5#2115

[njx]

FYI, it looks from the CM bug thread like Marijn has been trying to fix this, but is hampered by lack of a good way to detect grapheme clusters from JS. Maybe someone from Web Platform has some knowledge in this area?