ScreenSpaceUI.cs

//Free to use. Please mention my name "Eugene Chu" Twitter: @LenZ_Chu if you can ;3 https://twitter.com/LenZ_Chu
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ScreenSpaceUI
{

    // Use this for initialization
    /// <summary>
    /// UI follows target in scene around the canvas. Support aspect ratio, fixed ratio, and spherized clamp
    /// </summary>
    /// <param name="worldSpace_Tr">target</param>
    /// <param name="offSetWorldSpace">offset pos.</param>
    /// <param name="clampEdge">gives extra space to clamp edge of screen. 0-1 percent.</param>
    /// <param name="wrapAroundScreen">if target goes behind cam, it'll still stay on the edge.</param>
    /// <param name="ignoreAspectRatio">forces to clamps to ignore aspectRatio.</param>
    /// <param name="spherize">clamps into a sphere instead of boxed screen. 'Uses clampEdge.x' only.</param>
    /// <returns></returns>
    static public Vector3 ScreenSpace(Transform worldSpace_Tr, Vector2 offSetWorldSpace, Vector2 clampEdge, bool wrapAroundScreen = true, bool ignoreAspectRatio = false, bool spherize = false)
    {
        Vector3 screenPos = Camera.main.WorldToScreenPoint(worldSpace_Tr.position + (Camera.main.transform.right * offSetWorldSpace.x) + (worldSpace_Tr.up * offSetWorldSpace.y));

        Vector2 _rawClamp = new Vector2((Screen.width * Mathf.Clamp01(clampEdge.x)), (Screen.height * Mathf.Clamp01(clampEdge.y))) / 2; //conver to percentage;
        clampEdge = new Vector2((Screen.width * Mathf.Clamp01(1 - clampEdge.x)), (Screen.height * Mathf.Clamp01(1 - clampEdge.y))) / 2; //conver to percentage

        if (ignoreAspectRatio) clampEdge = new Vector2(clampEdge.x * Camera.main.aspect, clampEdge.y);

        //ON SCREEN
        // get the center of the screen and minus the percent of the offset for the left	//	get the center of the screen and minus the border percent for the right
        if (screenPos.z > 0 &&
            screenPos.x > 0 && screenPos.x < Screen.width &&
            screenPos.y > 0 && screenPos.y < Screen.height || (wrapAroundScreen))
        {

            if (spherize) //clamps sphere. uses clampEdge.x
            {
                Vector3 centerPt = new Vector3(Screen.width / 2, Screen.height / 2, 0);
                screenPos = centerPt + Vector3.ClampMagnitude(new Vector3((screenPos - centerPt).x, (screenPos - centerPt).y, 1), (_rawClamp.x)); //prevent z from being negative
            }
            else // clamps at the edges
            {
                screenPos = new Vector3(Mathf.Clamp(screenPos.x, clampEdge.x, Screen.width - clampEdge.x), Mathf.Clamp(screenPos.y, clampEdge.y, Screen.height - clampEdge.y), Mathf.Clamp(screenPos.z, 0, Mathf.Infinity));
            }
            //reverse
            if (screenPos.z < 0) screenPos = new Vector3(screenPos.x * -1, screenPos.y * -1, screenPos.z);

        }
        else
        {
            screenPos = screenPos * 1000;
        }
        // Debug.Log(screenPos);
        return screenPos;
    }
}