Created
May 12, 2020 13:08
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Selection History management window for Unity
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using System.Collections; | |
using System.Collections.Generic; | |
using UnityEditor; | |
using UnityEngine; | |
/// <summary> | |
/// Selection history window watches the selection and adds Forward and Back buttons to navigate previous selections. | |
/// </summary> | |
public class SelectionHistoryWindow : EditorWindow, IHasCustomMenu | |
{ | |
private const string BackMenuPath = "Edit/Select Previous #F1"; | |
private const string ForwardMenuPath = "Edit/Select Next #F2"; | |
private const string WindowMenuPath = "Window/Selection History Window"; | |
private const int HistorySize = 10; | |
private bool ignoreSelectionChange; | |
private int[] currentSelection; | |
private Stack<int[]> selectionHistory; | |
private Stack<int[]> poppedSelections; | |
/// <summary> | |
/// Implements IHasCutomMenu callback to add items into the right click menu and context menu on the window. | |
/// </summary> | |
/// <param name="menu">Menu to add into.</param> | |
public virtual void AddItemsToMenu(GenericMenu menu) | |
{ | |
menu.AddItem(new GUIContent("Clear History"), false, new GenericMenu.MenuFunction(this.ClearHistory)); | |
} | |
[MenuItem(WindowMenuPath)] | |
private static SelectionHistoryWindow OpenSelectionHistoryWindow() | |
{ | |
var window = EditorWindow.GetWindow<SelectionHistoryWindow>(false, "History"); | |
return window; | |
} | |
[MenuItem(BackMenuPath, false, 50)] | |
private static void BackMenuItem() | |
{ | |
var window = OpenSelectionHistoryWindow(); | |
window.MoveSelectionBack(); | |
} | |
[MenuItem(ForwardMenuPath, false, 51)] | |
private static void ForwardMenuItem() | |
{ | |
var window = OpenSelectionHistoryWindow(); | |
window.MoveSelectionForward(); | |
} | |
private void OnEnable() | |
{ | |
this.minSize = new Vector2(minSize.x, 25.0f); | |
// Note this clears selection every time the game recompiles. | |
this.poppedSelections = new Stack<int[]>(HistorySize); | |
this.selectionHistory = new Stack<int[]>(HistorySize); | |
} | |
private void ClearHistory() | |
{ | |
this.selectionHistory.Clear(); | |
this.poppedSelections.Clear(); | |
} | |
private void OnGUI() | |
{ | |
EditorGUILayout.BeginHorizontal(); | |
EditorGUI.BeginDisabledGroup(!this.IsBackEnabled()); | |
var leftArrowCode = "\u2190"; | |
if (GUILayout.Button(leftArrowCode, GUILayout.MinWidth(35))) | |
{ | |
this.MoveSelectionBack(); | |
} | |
EditorGUI.EndDisabledGroup(); | |
this.GUIDrawLabelForStack(this.selectionHistory, true); | |
GUILayout.FlexibleSpace(); | |
this.GUIDrawLabelForStack(this.poppedSelections, false); | |
EditorGUI.BeginDisabledGroup(!this.IsForwardEnabled()); | |
var rightArrowCode = "\u2192"; | |
if (GUILayout.Button(rightArrowCode, GUILayout.MinWidth(35))) | |
{ | |
this.MoveSelectionForward(); | |
} | |
EditorGUI.EndDisabledGroup(); | |
EditorGUILayout.EndHorizontal(); | |
} | |
private bool IsBackEnabled() | |
{ | |
if (this.selectionHistory == null) | |
{ | |
return false; | |
} | |
return this.selectionHistory.Count > 0; | |
} | |
private void MoveSelectionBack() | |
{ | |
if (this.IsBackEnabled()) | |
{ | |
this.PushCurrentSelectionAndPopNext(this.poppedSelections, this.selectionHistory); | |
} | |
} | |
private bool IsForwardEnabled() | |
{ | |
if (this.poppedSelections == null) | |
{ | |
return false; | |
} | |
return this.poppedSelections.Count > 0; | |
} | |
private void MoveSelectionForward() | |
{ | |
if (this.IsForwardEnabled()) | |
{ | |
this.PushCurrentSelectionAndPopNext(this.selectionHistory, this.poppedSelections); | |
} | |
} | |
private void PushCurrentSelectionAndPopNext(Stack<int[]> pushToStack, Stack<int[]> popFromStack) | |
{ | |
// Set flag so that this selection change is ignored during the selection callback | |
this.ignoreSelectionChange = true; | |
// Add current selection to a stack that maintains history | |
pushToStack.Push(this.currentSelection); | |
this.currentSelection = popFromStack.Pop(); | |
// Selected the popped value | |
Selection.instanceIDs = this.currentSelection; | |
} | |
private void GUIDrawLabelForStack(Stack<int[]> stack, bool alignLeft) | |
{ | |
var itemName = string.Empty; | |
if (stack.Count > 0) | |
{ | |
var nextItems = stack.Peek(); | |
itemName = this.GetStringForInstanceIDs(nextItems); | |
} | |
GUIStyle textStyle = new GUIStyle(EditorStyles.label); | |
textStyle.alignment = alignLeft ? TextAnchor.MiddleLeft : TextAnchor.MiddleRight; | |
EditorGUILayout.LabelField(itemName, textStyle, GUILayout.MinWidth(40), GUILayout.ExpandWidth(true)); | |
} | |
private void OnSelectionChange() | |
{ | |
if (this.ignoreSelectionChange) | |
{ | |
this.ignoreSelectionChange = false; | |
return; | |
} | |
// Push old selection onto the history, unless there is no selection (first selection ever) | |
if (this.currentSelection != null) | |
{ | |
// This is the same group. do not affect history | |
if (!this.IsSelectionAddative()) | |
{ | |
// Selection represents a new selection. | |
this.selectionHistory.Push(this.currentSelection); | |
} | |
} | |
this.currentSelection = Selection.instanceIDs; | |
// Clear forward history whenever any selection change is made | |
this.poppedSelections.Clear(); | |
this.Repaint(); | |
} | |
private bool IsSelectionAddative() | |
{ | |
var selectedIDs = Selection.instanceIDs; | |
// Can't be addative if only one thing is selected | |
if (selectedIDs.Length > 1) | |
{ | |
// If current (previous) selection contains one of the newly selected IDs, this must be a shift+select or drag select | |
for (int i = 0; i < this.currentSelection.Length; ++i) | |
{ | |
var currentSelectionID = this.currentSelection[i]; | |
for (int idIndex = 0; idIndex < selectedIDs.Length; ++idIndex) | |
{ | |
var id = selectedIDs[idIndex]; | |
if (id == currentSelectionID) | |
{ | |
return true; | |
} | |
} | |
} | |
} | |
return false; | |
} | |
private string GetStringForInstanceIDs(int[] ids) | |
{ | |
string name = string.Empty; | |
if (ids.Length > 0) | |
{ | |
var instanceID = ids[0]; | |
UnityEngine.Object firstObject = EditorUtility.InstanceIDToObject(instanceID); | |
if (firstObject != null) | |
{ | |
name = firstObject.name; | |
} | |
else | |
{ | |
name = "[Destroyed]"; | |
} | |
if (ids.Length > 1) | |
{ | |
name = string.Concat("[", ids.Length, "]", name); | |
} | |
} | |
else | |
{ | |
name = "[None]"; | |
} | |
return name; | |
} | |
} |
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