Objective C - 核心文本在位置查找索引？

Question

I am trying to get the index of the closest character to a point.

The code below works perfectly fine as ling as my text alignment is set to left, as soon as I chage it to right or center it gives me the wrong index. What would be the solution to consider the text alignment while getting closest index to a point?

CTLineRef line = (CTLineRef)[lines objectAtIndex:i];
index = CTLineGetStringIndexForPosition(line, point);  

EDIT:

My text alignment is done by adding a paragraph style that has it's textAlignment setting to kCTCenterTextAlignment

Answer 1

该点相对于线的原点（随着对齐而变化），因此您必须使用CTFrameGetLineOrigins并将线的原点的x值添加到点的x值。