UGUI源码学习

https://github.com/Unity-Technologies/uGUI/tree/2018.4

加了注释的源码 https://github.com/void87/TestForUGUI

https://www.cnblogs.com/revoid/p/6911699.html

layer主要通过光线投射来选择性地忽略碰撞器，或者添加碰撞功能。
而sorting layer就是一个渲染层级的顺序的控制。
决定Unity渲染关系的层级顺序是：
Camera 
sorting layer
sorting order

IME(Input Method Editor) 输入法编辑器

// The position of the pivot of this RectTransform relative to the anchor reference point
// 中心点相对于自身的锚点的为止
rectTransform.anchoredPosition

// Position of the transform relative to the parent transform
// 中心点相对于父物体中心点的位置
rectTransform.localPosition

Debug.Log(rectTransform.localPosition);
// Matrix that transforms a point from local space into world space
Vector3 worldPosition = rectTransform.localToWorldMatrix.MultiplyPoint(rectTransform.localPosition);
Debug.Log(worldPosition);
// Matrix that transforms a point from world space into local space
Vector3 localPosition = rectTransform.worldToLocalMatrix.MultiplyPoint(worldPosition);
Debug.Log(localPosition);

Vector3[] localCorners = new Vector3[4];
// Get the corners of the calculated rectangle in the local space of its Transform
// 获取localspace中的4个角的坐标
rectTransform.GetLocalCorners(localCorners);

Vector3[] worldCorners = new Vector3[4];
// Get the corners of the calculated rectangle in the local space of its Transform
// 获取worldspacee中的4个角的坐标
rectTransform.GetWorldCorners(worldCorners);

// The calculated rectangle in the local space of Transform
// 以左下角为原点的rect(x轴正方向为左,y轴正方向为下)
var rect = rectTransform.rect;
// The minimum X coordinate of the rectangle == left
var xMin = rect.xMin;
// The maximum Y coordinate of the rectangle == right
var xMax = rect.xMax;
// The minimum Y coordinate of the rectangle == top
var yMin = rect.yMin;
// The maximum Y coordinate of the rectangle == bottom
var yMax = rect.yMax;
// The X and Y position of the rectangle
// 中心点相对于rect左下角的点的位置
var rectPos = rect.position;

// 宽高
var with = rect.width;
var height = rect.height;
var size = rect.size;

// The position of the center of the rectangle
// 相对于rect的pivot的中心点
var center = rect.center;

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;

internal class ObjectPool<T> where T: new() {
    private readonly Stack<T> m_Stack = new Stack<T>();
    private readonly UnityAction<T> m_ActionOnGet;
    private readonly UnityAction<T> m_ActionOnRelease;

    public int countAll { get; private set; }
    public int countActive { get { return countAll - countInactive;  } }
    public int countInactive { get { return m_Stack.Count; } }

    public ObjectPool(UnityAction<T> actionOnGet, UnityAction<T> actionOnRelease) {
        m_ActionOnGet = actionOnGet;
        m_ActionOnRelease = actionOnRelease;
    }

    public T Get() {
        T element;
        if (m_Stack.Count== 0) {
            element = new T();
            countAll++;
        } else {
            element = m_Stack.Pop();
        }

        if (m_ActionOnGet != null) {
            m_ActionOnGet(element);
        }

        return element;
    }

    public void Release(T element) {
        if (m_Stack.Count > 0 && ReferenceEquals(m_Stack.Peek(), element)) {
            Debug.LogError("Internal error. Trying to destroy object that is already released to pool.");
        }

        if (m_ActionOnRelease != null) {
            m_ActionOnRelease(element);
        }
        m_Stack.Push(element);
    }
}

ObjectPool

internal static class ListPool<T> {
    private static readonly ObjectPool<List<T>> s_ListPool = new ObjectPool<List<T>>(null, Clear);
    static void Clear(List<T> l) { l.Clear(); }

    public static List<T> Get() {
        return s_ListPool.Get();
    }

    public static void Release(List<T> toRelease) {
        s_ListPool.Release(toRelease);
    }
}

ListPoool

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class IndexedSet<T> : IList<T> {
    //This is a container that gives:
    //  - Unique items
    //  - Fast random removal
    //  - Fast unique inclusion to the end
    //  - Sequential access
    //Downsides:
    //  - Uses more memory
    //  - Ordering is not persistent
    //  - Not Serialization Friendly.

    //We use a Dictionary to speed up list lookup, this makes it cheaper to guarantee no duplicates (set)
    //When removing we move the last item to the removed item position, this way we only need to update the index cache of a single item. (fast removal)
    //Order of the elements is not guaranteed. A removal will change the order of the items.

    readonly List<T> m_List = new List<T>();
    Dictionary<T, int> m_Dictionary = new Dictionary<T, int>();

    public void Add(T item) {
        m_List.Add(item);
        m_Dictionary.Add(item, m_List.Count - 1);
    }

    public bool AddUnique(T item) {
        if (m_Dictionary.ContainsKey(item))
            return false;

        m_List.Add(item);
        m_Dictionary.Add(item, m_List.Count - 1);

        return true;
    }

    public bool Remove(T item) {
        int index = -1;
        if (!m_Dictionary.TryGetValue(item, out index))
            return false;

        RemoveAt(index);
        return true;
    }

    public IEnumerator<T> GetEnumerator() {
        throw new System.NotImplementedException();
    }

    IEnumerator IEnumerable.GetEnumerator() {
        return GetEnumerator();
    }

    public void Clear() {
        m_List.Clear();
        m_Dictionary.Clear();
    }

    public bool Contains(T item) {
        return m_Dictionary.ContainsKey(item);
    }

    public void CopyTo(T[] array, int arrayIndex) {
        m_List.CopyTo(array, arrayIndex);
    }

    public int Count { get { return m_List.Count; } }
    public bool IsReadOnly { get { return false; } }
    public int IndexOf(T item) {
        int index = -1;
        m_Dictionary.TryGetValue(item, out index);
        return index;
    }

    public void Insert(int index, T item) {
        //We could support this, but the semantics would be weird. Order is not guaranteed..
        throw new NotSupportedException("Random Insertion is semantically invalid, since this structure does not guarantee ordering.");
    }

    public void RemoveAt(int index) {
        T item = m_List[index];
        m_Dictionary.Remove(item);
        if (index == m_List.Count - 1)
            m_List.RemoveAt(index);
        else {
            int replaceItemIndex = m_List.Count - 1;
            T replaceItem = m_List[replaceItemIndex];
            m_List[index] = replaceItem;
            m_Dictionary[replaceItem] = index;
            m_List.RemoveAt(replaceItemIndex);
        }
    }

    public T this[int index] {
        get { return m_List[index]; }
        set {
            T item = m_List[index];
            m_Dictionary.Remove(item);
            m_List[index] = value;
            m_Dictionary.Add(item, index);
        }
    }

    public void RemoveAll(Predicate<T> match) {
        //I guess this could be optmized by instead of removing the items from the list immediatly,
        //We move them to the end, and then remove all in one go.
        //But I don't think this is going to be the bottleneck, so leaving as is for now.
        int i = 0;
        while (i < m_List.Count) {
            T item = m_List[i];
            if (match(item))
                Remove(item);
            else
                i++;
        }
    }

    //Sorts the internal list, this makes the exposed index accessor sorted as well.
    //But note that any insertion or deletion, can unorder the collection again.
    public void Sort(Comparison<T> sortLayoutFunction) {
        //There might be better ways to sort and keep the dictionary index up to date.
        m_List.Sort(sortLayoutFunction);
        //Rebuild the dictionary index.
        for (int i = 0; i < m_List.Count; ++i) {
            T item = m_List[i];
            m_Dictionary[item] = i;
        }
    }
}

IndexedSet