PanelMoveResize (main)

using System;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace UI_controls {
    public class PanelMoveSize : MonoBehaviour {
        public enum SizableType {
            HorizontalLeft  = 0,
            HorizontalRight = 1,
            VerticalTop     = 2,
            VerticalBottom  = 4
        }

        public enum MovableType {
            Top    = 0,
            Bottom = 1,
            Left   = 2,
            Right  = 3
        }

        public float stickDistance = 20f;

        public float minWidth;
        public float maxWidth;
        public float minHeight;
        public float maxHeight;

        public  RectTransform rTr   { get; private set; }
        public  Vector2       scale => parentCanvas.localScale;
        private RectTransform parentCanvas;
        private Image         image;

        void Start() {
            rTr          = (RectTransform) transform;
            parentCanvas = (RectTransform) gameObject.GetComponentInParent<Canvas>().transform;
            image        = GetComponent<Image>();
            image.sprite = MainDatabase.PanelViewSo.background;
            image.color  = MainDatabase.PanelViewSo.backgroundColor;
        }

        public void Resize(Vector2 delta, SizableType type) {
            var sd = rTr.sizeDelta;
            switch (type) {
                case SizableType.HorizontalLeft:
                    sd.x = delta.x;
                    break;
                case SizableType.HorizontalRight:
                    sd.x = delta.x;
                    break;
                case SizableType.VerticalTop:
                    sd.y = delta.y;
                    break;
                case SizableType.VerticalBottom:
                    sd.y = delta.y;
                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(type), type, null);
            }
            sd.x = Mathf.Clamp(sd.x, minWidth,  maxWidth  < minWidth ? sd.x : maxWidth);
            sd.y = Mathf.Clamp(sd.y, minHeight, maxHeight < minHeight ? sd.y : maxHeight);

            Vector2 ap;
            var     sd2 = sd - rTr.sizeDelta;
            switch (type) {
                case SizableType.HorizontalLeft:
                    ap = new Vector2(sd2.x * (1f - rTr.pivot.x), 0f);
                    break;
                case SizableType.HorizontalRight:
                    ap = new Vector2(sd2.x * rTr.pivot.x, 0f);
                    break;
                case SizableType.VerticalTop:
                    ap = new Vector2(0f, sd2.y * rTr.pivot.y);
                    break;
                case SizableType.VerticalBottom:
                    ap = new Vector2(0f, -sd2.y * (1f - rTr.pivot.y));
                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(type), type, null);
            }

            rTr.sizeDelta = sd;
            CheckOnScreen(rTr.anchoredPosition + ap);
        }

        public void Move(Vector2 position) {
            var e = position;
            CheckOnScreen(e);
        }

        public void CheckOnScreen(Vector2 newPos) {
            var rect = rTr.rect;

            if (rect.xMin + newPos.x < stickDistance) newPos.x                            = -rect.xMin;
            if (rect.xMax + newPos.x > parentCanvas.sizeDelta.x - stickDistance) newPos.x = parentCanvas.sizeDelta.x - rect.xMax;

            if (newPos.y + rect.yMax > -stickDistance) newPos.y                            = -(rect.yMax);
            if (newPos.y + rect.yMin < -parentCanvas.sizeDelta.y + stickDistance) newPos.y = -(parentCanvas.sizeDelta.y + rect.yMin);

            rTr.anchoredPosition = newPos;
        }
    }
}