Unity用UGUI制作颜色拾取
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)));
}
}
}
