Unity用UGUI制作颜色拾取

2020-08-14  本文已影响0人  runinnn

使用ugui做一个可以吸取屏幕上图片的颜色的功能。

然后主要用到的知识点就是

这个方法了:Texture2D.GetPixel:

1)函数形式

public Color GetPixel(int x, int y);

2)功能描述

Returns pixel color at coordinates (x, y).

If the pixel coordinates are out of bounds (larger than width/height or small than 0), they will be clamped or repeated based on the texture's wrap modeTexture coordinates start at lower left cornerIf you are reading a large block of pixels from the texture, it may be faster to use GetPixels32 or GetPixels which returns a whole block of pixel colorsThe texture must have the Read/Write Enabled flag set in the import settings, otherwise this function will fail. GetPixel is not available on Textures using Crunch texture compression.

有两种比较简单粗暴的方法:

1、就是直接以整个屏幕做为对象拾取对应点的颜色;

2、就是用显示的图片自身的Textured2D图片获取对应位置的像素;

首先就是先找一张热度颜色图,

用第一种方法的话,就不用对这个图片做任何处理,只需要放在场景中以供选择颜色使用;

用第二种方法呢,就必须要注重一点:就是图片属性的“Read/Write Enabled“必须选中,不然就读取不到图片的像素。

如下图”:

然后就是代码部分了:

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using UnityEngine.UI;

using UnityEngine.EventSystems;

using UnityEngine.Events;

public class CatchColor : MonoBehaviour,IPointerUpHandler

{

    /// <summary>

    /// 捕捉的颜色

    /// </summary>

    public Color ReturnColor;

    public Image GetColorImage;

    private RectTransform GetColorImageRect;

    private void Start()

    {

        if (GetColorImage)

        {

            GetColorImageRect = GetColorImage.gameObject.GetComponent<RectTransform>();

            // 添加鼠标事件

            EventTrigger testET = GetColorImageRect.gameObject.AddComponent<EventTrigger>();

            testET.triggers = new List<EventTrigger.Entry>();

            EventTrigger.Entry entryUp = new EventTrigger.Entry();

            entryUp.eventID = EventTriggerType.PointerUp;

            entryUp.callback = new EventTrigger.TriggerEvent();

            // 抬起回调

            UnityAction<BaseEventData> upCB = new UnityAction<BaseEventData>((BaseEventData bed) => {

                OnPointerUp();

            });

            entryUp.callback.AddListener(upCB);

            testET.triggers.Add(entryUp);

        }

    }

    public void OnPointerUp(PointerEventData eventData)

    {

        StopCoroutine(CalColor(eventData));

        StartCoroutine(CalColor(eventData));

    }

    public void OnPointerUp()

    {

        StopCoroutine(CalColor(null));

        StartCoroutine(CalColor(null));

    }

    private IEnumerator CalColor(PointerEventData eventData)

    {

        //在每一帧渲染完成后读取信息

        yield return new WaitForEndOfFrame();

        //GetColorByScreen();

        GetColorByTexture(eventData);

    }

    /// <summary>

    /// 基于屏幕读取点的颜色

    /// </summary>

    private void GetColorByScreen()

    {

        Texture2D texture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24,false);

        //读取Rect范围内的像素写入纹理中

        texture.ReadPixels(new Rect(0,0,Screen.width,Screen.height),0,0);

        texture.Apply();//实际应用

        ReturnColor = texture.GetPixel(Mathf.FloorToInt(Input.mousePosition.x), Mathf.FloorToInt(Input.mousePosition.y));

    }

    /// <summary>

    /// 直接通过自身的Texture获取

    /// </summary>

    private void GetColorByTexture(PointerEventData eventData) {

        Vector2 clickPosition = Vector2.zero;

        if (GetColorImage && eventData != null)

        {

            //获取鼠标点击的对应GetColorImageRect的位置坐标

            RectTransformUtility.ScreenPointToLocalPointInRectangle(GetColorImageRect,eventData.position,eventData.enterEventCamera,out clickPosition);

            ReturnColor = GetColorImage.sprite.texture.GetPixel(Mathf.FloorToInt(clickPosition.x + (GetColorImageRect.rect.width / 2)), Mathf.FloorToInt(clickPosition.y + (GetColorImageRect.rect.height / 2)));

        }

    }

}

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