Unity中的物体缩放-Android和PC平台

在本文中缩放的是NGUI的Texture对象：

在一个有Collider的可以控制Texture的对象上添加如下脚本即可：

Texture是此对象的子物体，即ScaleDragTexture组件中的Image对象。

using UnityEngine;

public class ScaleDragTexture : MonoBehaviour
{
    public Transform uitexture;
    //当触屏点超过1个时，对图片进行放大和缩小，最小缩放比例为图片加载时大小    
    private float newdis;   //两个手指之间的距离
    private float olddis;
    private float minScale = 1.0f;     //放大比例
    private float maxScale = 2.0f;
    private float curScale = 1.0f;
    private Vector3 uitextureDefaultScale;
    private Vector3 uitextureCurScale;

    void Update()
    {
        if (Application.platform == RuntimePlatform.Android)
        {
            //物体的缩放 
            if (Input.touchCount > 1)
            {
                this.GetComponent<UIDragObject>().enabled = false;  //将DragObject脚本设置为不可用，来控制缩放的时候不进行拖拽
                if (uitextureDefaultScale != this.GetComponent<UpdateImage>().uitextureDefaultScale)
                {//获取图片未被拖拽时（默认状态）的缩放值
                    uitextureDefaultScale = uitextureCurScale = this.GetComponent<UpdateImage>().uitextureDefaultScale;
                }
                if (Input.GetTouch(0).phase == TouchPhase.Moved || Input.GetTouch(1).phase == TouchPhase.Moved)
                {
                    var pos1 = Input.GetTouch(0).position;
                    var pos2 = Input.GetTouch(1).position;
                    newdis = Vector2.Distance(pos1, pos2);//获取两个触击点的距离
                    curScale = uitextureCurScale.x / uitextureDefaultScale.x;   //获取当前的缩放比例值
                    if (newdis < olddis)
                    {//比例缩小
                        if (curScale > maxScale || curScale > minScale)
                            uitexture.localScale -= uitextureDefaultScale * Time.deltaTime;
                    }
                    if (newdis > olddis)
                    {//比例放大
                        if (curScale <= maxScale)
                            uitexture.localScale += uitextureDefaultScale * Time.deltaTime;
                    }
                    if (curScale < minScale)
                    {//当前比例小于最小值时恢复到默认缩放值
                        uitexture.localScale = uitextureDefaultScale;
                    }
                    uitextureCurScale = uitexture.localScale;
                    olddis = newdis;
                }
                if (curScale == minScale)
                {//图片未进行缩放时，只有Y轴上可以被拖动
                    this.GetComponent<UIDragObject>().scale = new Vector3(0, 1, 0);
                }
                else
                {//当图片缩放后，在X、Y轴上可以被拖动
                    this.GetComponent<UIDragObject>().scale = new Vector3(1, 1, 0);
                }
            }
            else if (Input.touchCount == 1)
            {
                this.GetComponent<UIDragObject>().enabled = true;  //将DragObject脚本设置为可用
            }
        }

        else
        {
            if (Input.GetMouseButton(2))    //鼠标中键
            {
                this.GetComponent<UIDragObject>().enabled = false;  //将DragObject脚本设置为不可用，来控制缩放的时候不进行拖拽

                if (uitextureDefaultScale != this.GetComponent<UpdateImage>().uitextureDefaultScale)
                {//获取图片未进行缩放时的Scale值
                    uitextureDefaultScale = uitextureCurScale = this.GetComponent<UpdateImage>().uitextureDefaultScale;
                }
                curScale = uitextureCurScale.x / uitextureDefaultScale.x;   //获取当前的缩放比例值
                if (Input.GetAxis("Mouse ScrollWheel") < 0)
                {//比例放大
                    if (curScale <= maxScale)
                        uitexture.localScale += uitextureDefaultScale * Time.deltaTime;
                }
                else if (Input.GetAxis("Mouse ScrollWheel") > 0)
                {//比例缩小
                    if (curScale > minScale || curScale > maxScale)
                        uitexture.localScale -= uitextureDefaultScale * Time.deltaTime;
                }
                if (uitexture.localScale.x < uitextureDefaultScale.x)
                {//当缩放的值小于默认值时，恢复到默认值
                    uitexture.localScale = uitextureDefaultScale;
                }
                uitextureCurScale = uitexture.localScale;
                if (curScale == minScale)
                {//默认未进行缩放时只有Y轴上可以被拖动
                    this.GetComponent<UIDragObject>().scale = new Vector3(0, 1, 0);
                }
                else
                {//缩放之后X、Y轴上可以被拖动
                    this.GetComponent<UIDragObject>().scale = new Vector3(1, 1, 0);
                }
            }
            else if (Input.GetMouseButtonDown(0))
            {
                this.GetComponent<UIDragObject>().enabled = true;  //将DragObject脚本设置为可用
            }
        }
    }
}