From 1776ab592d38a29178393d1c4c9b93e5bcff49a4 Mon Sep 17 00:00:00 2001
From: tibbi <tibor@kaputa.sk>
Date: Sun, 13 Jan 2019 18:02:06 +0100
Subject: [PATCH] adding an Undo button to editor drawing

---
 .../gallery/pro/activities/EditActivity.kt    |  4 ++++
 .../gallery/pro/views/EditorDrawCanvas.kt     | 10 ++++++++++
 .../res/layout/bottom_editor_draw_actions.xml | 19 ++++++++++++++++---
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/pro/activities/EditActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/pro/activities/EditActivity.kt
index b14e064e2..0cc34a601 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/pro/activities/EditActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/pro/activities/EditActivity.kt
@@ -460,6 +460,10 @@ class EditActivity : SimpleActivity(), CropImageView.OnCropImageCompleteListener
             config.lastEditorBrushSize = it
             updateBrushSize(it)
         }
+
+        bottom_draw_undo.setOnClickListener {
+            editor_draw_canvas.undo()
+        }
     }
 
     private fun updateBrushSize(percent: Int) {
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/pro/views/EditorDrawCanvas.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/pro/views/EditorDrawCanvas.kt
index 0551cc963..8d1ee75b7 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/pro/views/EditorDrawCanvas.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/pro/views/EditorDrawCanvas.kt
@@ -139,4 +139,14 @@ class EditorDrawCanvas(context: Context, attrs: AttributeSet) : View(context, at
         draw(canvas)
         return bitmap
     }
+
+    fun undo() {
+        if (mPaths.isEmpty()) {
+            return
+        }
+
+        val lastKey = mPaths.keys.lastOrNull()
+        mPaths.remove(lastKey)
+        invalidate()
+    }
 }
diff --git a/app/src/main/res/layout/bottom_editor_draw_actions.xml b/app/src/main/res/layout/bottom_editor_draw_actions.xml
index d88f7b995..fb12e40b2 100644
--- a/app/src/main/res/layout/bottom_editor_draw_actions.xml
+++ b/app/src/main/res/layout/bottom_editor_draw_actions.xml
@@ -24,21 +24,34 @@
         android:id="@+id/bottom_draw_color_clickable"
         android:layout_width="@dimen/bottom_editor_color_picker_size"
         android:layout_height="@dimen/bottom_editor_color_picker_size"
-        android:layout_marginRight="@dimen/activity_margin"
+        android:layout_marginRight="@dimen/small_margin"
         android:background="?attr/selectableItemBackgroundBorderless"
         app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintRight_toLeftOf="@+id/bottom_draw_undo"
         app:layout_constraintTop_toTopOf="parent"/>
 
     <ImageView
         android:id="@+id/bottom_draw_color"
         android:layout_width="@dimen/bottom_editor_color_picker_size"
         android:layout_height="@dimen/bottom_editor_color_picker_size"
-        android:layout_marginRight="@dimen/activity_margin"
+        android:layout_marginRight="@dimen/small_margin"
         android:clickable="false"
         android:padding="@dimen/small_margin"
         android:src="@drawable/circle_background"
         app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintRight_toLeftOf="@+id/bottom_draw_undo"
+        app:layout_constraintTop_toTopOf="parent"/>
+
+    <ImageView
+        android:id="@+id/bottom_draw_undo"
+        android:layout_width="@dimen/bottom_editor_color_picker_size"
+        android:layout_height="@dimen/bottom_editor_color_picker_size"
+        android:layout_marginRight="@dimen/normal_margin"
+        android:background="?attr/selectableItemBackgroundBorderless"
+        android:clickable="false"
+        android:padding="@dimen/medium_margin"
+        android:src="@drawable/ic_undo"
+        app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintRight_toRightOf="parent"
         app:layout_constraintTop_toTopOf="parent"/>