How can I create complex tooltips

Use GUITextures and GUIText, these can be found under the GameObject -> create other menu.

These are tricky to work with, but so powerful when you get a grip on it!

I suggest you to read this

Hello! as NickP suggested, it is often better to use GUIElements as they are only called when they are updated rather than OnGUI which is often called ~twice per frame although as he also mentioned they are much harder to work with on trickier problems and I think as you can only have 1 tooltip active at a time it may be better to use the OnGUI method for your problem.

The main part of this code is the custom class MyGUI.Tooltip. It requires a few arguments to be passed to it:

1. position : Vector2 => the position of the top, right corner of the tooltip

2. imageSize : int => the size that images should be displayed

3. spacer : int => a spacing value, to have some gaps between images

4. images : Texture2D[] => a list of the images you want shown

5. string : String => the string you want written

The is an example of how you can call it using a GUI.tooltip value in the OnGUI method.

Code

 import System;
 
 private var index : int;
 private var imageList;
 var imageList0 : Texture2D[];
 var imageList1 : Texture2D[];
 var imageList2 : Texture2D[];
 var stringList : String[] = ["I am the first tooltip!", "im the second tooltip though my index is 1", "3"];
 
 var imageSize : int = 32;
 var spacerSize : int = 5;
 
 public class MyGUI{
     public static function Tooltip(position : Vector2, imageSize : int, spacer : int, images : Texture2D[], string : String){
         var stringSize = GUI.skin.GetStyle("Box").CalcSize(GUIContent(string));
         var imagePanel : Vector2 = Vector2(
             imageSize*images.Length + spacer*Mathf.Max(0, images.Length-1) + spacer,
             (imageSize+spacer)*Mathf.Min(1, images.Length) + spacer);
         var tooltipSize = Vector2(
             Mathf.Max(stringSize.x, imagePanel.x) + spacer,
             imagePanel.y + stringSize.y + spacer);
         GUI.BeginGroup(Rect(position.x, position.y, tooltipSize.x, tooltipSize.y));
             GUI.Box(Rect(0, 0, tooltipSize.x, tooltipSize.y), "");
             GUI.Label(
                 Rect(3 + (tooltipSize.x-stringSize.x)/2.0,
                 imagePanel.y,
                 stringSize.x,
                 stringSize.y),
                 string);
             var imageSpacer = (tooltipSize.x - images.Length*imageSize)/(images.Length+1);
             for(var i = 0; i < images.Length; i++){
                 GUI.DrawTexture(Rect(imageSpacer + i*(imageSize+imageSpacer), spacer, imageSize, imageSize), images[i]);
             }
         GUI.EndGroup();
     }
 }
 
 function Start(){
     imageList = [imageList0, imageList1, imageList2];
 }
 
 
 function OnGUI(){
     GUI.Box (Rect (10, 10, 20, 20), GUIContent("", "0"));
     GUI.Box (Rect (40, 10, 20, 20), GUIContent("", "1"));
     GUI.Box (Rect (70, 10, 20, 20), GUIContent("", "2"));
     
     if(GUI.tooltip != ""){
         try{
             index = Int32.Parse(GUI.tooltip);
             MyGUI.Tooltip(Vector2(Input.mousePosition.x, Screen.height - Input.mousePosition.y),
                 imageSize,
                 spacerSize,
                 imageList[index],
                 stringList[index]);
         }catch(err : System.FormatException){
         }
     }
 }

Scribe