unity 两指缩放图片在一定范围内，两指旋转图片，单击恢复图片原始大小和旋转，按住拖动图片位置在一定范围内

要实现在Unity中使用手势控制图片的缩放、旋转和拖动，您可以使用`Touch`和`Input`类来检测手势，并使用`transform`组件来控制图片的变换。

以下是一个简单的示例代码，演示了如何实现手势控制图片的缩放、旋转和拖动：

using UnityEngine;

public class ImageController : MonoBehaviour
{
    private Vector3 touchStart;
    private float rotationSpeed = 0.2f;
    private float zoomSpeed = 0.02f;
    private float minZoom = 0.5f;
    private float maxZoom = 2f;
    private float minX = -2f;
    private float maxX = 2f;
    private float minY = -2f;
    private float maxY = 2f;

    // Update is called once per frame
    void Update()
    {
        // Check if there are two touches
        if (Input.touchCount == 2)
        {
            // Get the two touches
            Touch touchZero = Input.GetTouch(0);
            Touch touchOne = Input.GetTouch(1);

            // Check if the touches moved
            if (touchZero.phase == TouchPhase.Moved || touchOne.phase == TouchPhase.Moved)
            {
                // Calculate the distance and angle between the touches
                Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
                Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;
                float prevTouchDeltaMag = (touchZeroPrevPos - touchOnePrevPos).magnitude;
                float touchDeltaMag = (touchZero.position - touchOne.position).magnitude;
                float deltaMagnitudeDiff = prevTouchDeltaMag - touchDeltaMag;
                float angle = Vector2.Angle(touchZero.position - touchOne.position, touchZeroPrevPos - touchOnePrevPos);

                // Zoom the image
                Vector3 scale = transform.localScale;
                scale += new Vector3(1, 1, 1) * deltaMagnitudeDiff * zoomSpeed;
                scale = new Vector3(
                    Mathf.Clamp(scale.x, minZoom, maxZoom),
                    Mathf.Clamp(scale.y, minZoom, maxZoom),
                    Mathf.Clamp(scale.z, minZoom, maxZoom));
                transform.localScale = scale;

                // Rotate the image
                if (angle > 0.1f)
                {
                    Vector3 axis = Vector3.Cross(touchZero.position - touchOne.position, touchZeroPrevPos - touchOnePrevPos);
                    transform.Rotate(axis, angle * rotationSpeed, Space.World);
                }
            }
        }
        // Check if there is one touch
        else if (Input.touchCount == 1)
        {
            Touch touch = Input.GetTouch(0);

            // Check if the touch began
            if (touch.phase == TouchPhase.Began)
            {
                touchStart = touch.position;
            }
            // Check if the touch moved
            else if (touch.phase == TouchPhase.Moved)
            {
                // Move the image
                Vector3 pos = transform.position;
                pos += new Vector3(-touch.deltaPosition.x, -touch.deltaPosition.y, 0) * 0.01f;
                pos = new Vector3(
                    Mathf.Clamp(pos.x, minX, maxX),
                    Mathf.Clamp(pos.y, minY, maxY),
                    pos.z);
                transform.position = pos;
            }
            // Check if the touch ended
            else if (touch.phase == TouchPhase.Ended)
            {
                // Check if the touch was a tap
                if ((touch.position - touchStart).magnitude < 10f)
                {
                    // Reset the image
                    transform.position = Vector3.zero;
                    transform.rotation = Quaternion.identity;
                    transform.localScale = Vector3.one;
                }
            }
        }
    }
}

这个代码将检测手势，并根据手势缩放、旋转和拖动图片。您可以根据需要调整变量的值来限制图片的缩放范围、旋转范围和拖动范围。