From 807205b93a7c8a7ff58aa28f3bb9d6a1d2e9978a Mon Sep 17 00:00:00 2001
From: Michal Wolski <mwolski@waskysoft.pl>
Date: Wed, 17 Jul 2024 15:10:15 +0200
Subject: [PATCH] Add undoStackCount, isUndoAvailable, isRedoAvailable in
 PhotoEditor

---
 .../photoediting/EditImageActivity.kt         | 12 +++++------
 .../burhanrashid52/photoeditor/PhotoEditor.kt | 21 +++++++++++++++++++
 .../photoeditor/PhotoEditorImpl.kt            |  7 ++++---
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/app/src/main/java/com/burhanrashid52/photoediting/EditImageActivity.kt b/app/src/main/java/com/burhanrashid52/photoediting/EditImageActivity.kt
index 06a43a2f..48869ced 100644
--- a/app/src/main/java/com/burhanrashid52/photoediting/EditImageActivity.kt
+++ b/app/src/main/java/com/burhanrashid52/photoediting/EditImageActivity.kt
@@ -206,8 +206,8 @@ class EditImageActivity : BaseActivity(), OnPhotoEditorListener, View.OnClickLis
             "onAddViewListener() called with: viewType = [$viewType], numberOfAddedViews = [$numberOfAddedViews]"
         )
 
-        mImgUndo.isEnabled = !mPhotoEditor.isCacheEmpty
-        mImgRedo.isEnabled = mPhotoEditor.redoStackCount > 0
+        mImgUndo.isEnabled = mPhotoEditor.isUndoAvailable
+        mImgRedo.isEnabled = mPhotoEditor.isRedoAvailable
     }
 
     override fun onRemoveViewListener(viewType: ViewType, numberOfAddedViews: Int) {
@@ -216,8 +216,8 @@ class EditImageActivity : BaseActivity(), OnPhotoEditorListener, View.OnClickLis
             "onRemoveViewListener() called with: viewType = [$viewType], numberOfAddedViews = [$numberOfAddedViews]"
         )
 
-        mImgUndo.isEnabled = !mPhotoEditor.isCacheEmpty
-        mImgRedo.isEnabled = mPhotoEditor.redoStackCount > 0
+        mImgUndo.isEnabled = mPhotoEditor.isUndoAvailable
+        mImgRedo.isEnabled = mPhotoEditor.isRedoAvailable
     }
 
     override fun onStartViewChangeListener(viewType: ViewType) {
@@ -237,11 +237,11 @@ class EditImageActivity : BaseActivity(), OnPhotoEditorListener, View.OnClickLis
         when (view.id) {
             R.id.imgUndo -> {
                 mImgUndo.isEnabled = mPhotoEditor.undo()
-                mImgRedo.isEnabled = mPhotoEditor.redoStackCount > 0
+                mImgRedo.isEnabled = mPhotoEditor.isRedoAvailable
             }
 
             R.id.imgRedo -> {
-                mImgUndo.isEnabled = !mPhotoEditor.isCacheEmpty
+                mImgUndo.isEnabled = mPhotoEditor.isUndoAvailable
                 mImgRedo.isEnabled = mPhotoEditor.redo()
             }
 
diff --git a/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditor.kt b/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditor.kt
index a12e7c2f..587a0762 100644
--- a/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditor.kt
+++ b/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditor.kt
@@ -186,6 +186,20 @@ interface PhotoEditor {
      */
     fun undo(): Boolean
 
+    /**
+     * How many undo operations are available.
+     *
+     * @return size of undo stack
+     */
+    val undoStackCount: Int
+
+    /**
+     * Returns whether any undo operation is available.
+     *
+     * @return `true` if no undo operations available, `false` otherwise
+     */
+    val isUndoAvailable get() = undoStackCount > 0
+
     /**
      * Redo the last operation perform on the [PhotoEditor]
      *
@@ -200,6 +214,13 @@ interface PhotoEditor {
      */
     val redoStackCount: Int
 
+    /**
+     * Returns whether any redo operation is available.
+     *
+     * @return `true` if no redo operations available, `false` otherwise
+     */
+    val isRedoAvailable get() = redoStackCount > 0
+
     /**
      * Removes all the edited operations performed [PhotoEditorView]
      * This will also clear the undo and redo stack
diff --git a/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditorImpl.kt b/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditorImpl.kt
index b567d302..37604ee5 100644
--- a/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditorImpl.kt
+++ b/photoeditor/src/main/java/ja/burhanrashid52/photoeditor/PhotoEditorImpl.kt
@@ -188,12 +188,13 @@ internal class PhotoEditorImpl @SuppressLint("ClickableViewAccessibility") const
         return mGraphicManager.undoView()
     }
 
+    override val undoStackCount: Int get() = viewState.addedViewsCount
+
     override fun redo(): Boolean {
         return mGraphicManager.redoView()
     }
 
-    override val redoStackCount: Int
-        get() = mGraphicManager.redoStackCount
+    override val redoStackCount: Int get() = mGraphicManager.redoStackCount
 
     override fun clearAllViews() {
         mBoxHelper.clearAllViews(drawingView)
@@ -266,7 +267,7 @@ internal class PhotoEditorImpl @SuppressLint("ClickableViewAccessibility") const
     }
 
     override val isCacheEmpty: Boolean
-        get() = viewState.addedViewsCount == 0 && viewState.redoViewsCount == 0
+        get() = !isUndoAvailable && !isRedoAvailable
 
     // region Shape
     override fun setShape(shapeBuilder: ShapeBuilder) {