GUIStyle.GetCursorStringIndex 获取光标字符串索引

function GetCursorStringIndex (position : Rect, content : GUIContent, cursorPixelPosition : Vector2) : int

Description描述

Get the cursor position (indexing into contents.text) when the user clicked at cursorPixelPosition

当用户在cursorPixelPosition点击，获取光标位置（索引到contents.text）

This does not respect any images inside content.

这个方法不考虑内容里的任意图像。