From 8ab838c99914e80237aeac6ae13df0ec6fccaf69 Mon Sep 17 00:00:00 2001
From: Thomas Baum <thomas.baum@atns.de>
Date: Wed, 9 Sep 2020 18:56:07 +0200
Subject: [PATCH] expose redo/undo state

---
 .../aia-image-annotator.component.ts                 | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/projects/aia-lib/src/lib/components/aia-image-annotator/aia-image-annotator.component.ts b/projects/aia-lib/src/lib/components/aia-image-annotator/aia-image-annotator.component.ts
index ff711a4..ee45cc9 100644
--- a/projects/aia-lib/src/lib/components/aia-image-annotator/aia-image-annotator.component.ts
+++ b/projects/aia-lib/src/lib/components/aia-image-annotator/aia-image-annotator.component.ts
@@ -110,19 +110,23 @@ export class AiaImageAnnotatorComponent implements OnInit, OnChanges {
    * Undo last action
    */
   public undo() {
-    if (!this._drawCommands.length) {
+    if (!this.canUndo) {
       return;
     }
     this._redoCommands.push(this._drawCommands.pop());
     this.clearCanvas();
     this.drawCommandsOnCanvas(this._drawCommands, this.drawingCtx);
   }
+  
+  public get canUndo() {
+    return !!this._drawCommands.length
+  }
 
   /**
    * Redo last undone action if available
    */
   public redo() {
-    if (!this._redoCommands.length) {
+    if (!this.canRedo) {
       return;
     }
     this._drawCommands.push(this._redoCommands.pop());
@@ -130,6 +134,10 @@ export class AiaImageAnnotatorComponent implements OnInit, OnChanges {
     this.drawCommandsOnCanvas(this._drawCommands, this.drawingCtx);
   }
 
+  public get canRedo() {
+    return !!this._redoCommands.length
+  }
+
   /**
    * Clears canvas undo-ably
    */