A very hacky undo redo implementation

src/FileFormat/AkiraFile.vala

@@ -59,7 +59,7 @@ public class Akira.FileFormat.AkiraFile : Akira.FileFormat.ZipArchiveHandler {
             save_images.begin ();
             var content = new FileFormat.JsonContent (window);
 
-            content.save_content ();
+            content.inner_save_content ();
             var json = content.finalize_content ();
             write_content_to_file (content_file, json);
 

src/FileFormat/JsonContent.vala

@@ -40,7 +40,20 @@ public class Akira.FileFormat.JsonContent : Object {
         canvas = window.main_window.main_canvas.canvas;
     }
 
-    public void save_content () {
+    public string finalize_content () {
+        builder.end_object ();
+
+        Json.Node root = builder.get_root ();
+        generator.set_root (root);
+
+        return generator.to_data (null);
+    }
+
+    public void inner_save_content() {
+        save_content(builder, canvas);
+    }
+
+    public static void save_content (Json.Builder builder, Akira.Lib.Canvas canvas) {
         // Save the current version of Akira.
         builder.set_member_name ("version");
         builder.add_string_value (Constants.VERSION);
@@ -49,22 +62,22 @@ public class Akira.FileFormat.JsonContent : Object {
         builder.set_member_name ("scale");
         builder.add_double_value (canvas.get_scale ());
         builder.set_member_name ("hadjustment");
-        builder.add_double_value (window.main_window.main_canvas.main_scroll.hadjustment.value);
+        builder.add_double_value (0);
         builder.set_member_name ("vadjustment");
-        builder.add_double_value (window.main_window.main_canvas.main_scroll.vadjustment.value);
+        builder.add_double_value (0);
 
         // Convert Artboards to JSON.
-        save_artboards ();
+        save_artboards (builder, canvas);
 
         // Convert Items to JSON.
-        save_items ();
+        save_items (builder, canvas);
     }
 
-    private void save_artboards () {
+    private static void save_artboards (Json.Builder builder, Akira.Lib.Canvas canvas) {
         builder.set_member_name ("artboards");
         builder.begin_array ();
 
-        foreach (var artboard in window.items_manager.artboards) {
+        foreach (var artboard in canvas.window.items_manager.artboards) {
             var item = new JsonObject (artboard);
             builder.begin_object ();
             builder.set_member_name ("artboard");
@@ -75,11 +88,11 @@ public class Akira.FileFormat.JsonContent : Object {
         builder.end_array ();
     }
 
-    private void save_items () {
+    private static void save_items (Json.Builder builder, Akira.Lib.Canvas canvas) {
         builder.set_member_name ("items");
         builder.begin_array ();
 
-        foreach (var _item in window.items_manager.free_items) {
+        foreach (var _item in canvas.window.items_manager.free_items) {
             var item = new JsonObject (_item);
             builder.begin_object ();
             builder.set_member_name ("item");
@@ -88,7 +101,7 @@ public class Akira.FileFormat.JsonContent : Object {
         }
 
         // Save all the items inside this Artboard.
-        foreach (var artboard in window.items_manager.artboards) {
+        foreach (var artboard in canvas.window.items_manager.artboards) {
             foreach (var _item in artboard.items) {
                 var child_item = new JsonObject (_item);
                 builder.begin_object ();
@@ -101,12 +114,19 @@ public class Akira.FileFormat.JsonContent : Object {
         builder.end_array ();
     }
 
-    public string finalize_content () {
-        builder.end_object ();
+    public static string serialize_canvas (Akira.Lib.Canvas canvas) {
+        var inner_generator = new Json.Generator ();
+        inner_generator.pretty = true;
+        var inner_builder = new Json.Builder ();
+        inner_builder.begin_object ();
 
-        Json.Node root = builder.get_root ();
-        generator.set_root (root);
+        save_content(inner_builder, canvas);
 
-        return generator.to_data (null);
+        inner_builder.end_object ();
+
+        Json.Node root = inner_builder.get_root ();
+        inner_generator.set_root (root);
+
+        return inner_generator.to_data (null);
     }
 }

src/FileFormat/JsonLoader.vala

@@ -33,47 +33,51 @@ public class Akira.FileFormat.JsonLoader : Object {
     construct {
         load_content ();
     }
-
     public void load_content () {
+        inner_load_content(window.main_window.main_canvas.canvas, obj);
+
+    }
+
+    public static void inner_load_content (Akira.Lib.Canvas canvas, Json.Object json_object) {
         // Se the canvas to simulate a click + holding state to avoid triggering
         // redrawing methods connected to that state.
-        window.main_window.main_canvas.canvas.holding = true;
+        canvas.holding = true;
 
         // Load saved Artboards.
-        if (obj.get_member ("artboards") != null) {
-            Json.Array artboards = obj.get_member ("artboards").get_array ();
+        if (json_object.get_member ("artboards") != null) {
+            Json.Array artboards = json_object.get_member ("artboards").get_array ();
             var artboards_list = artboards.get_elements ();
             artboards_list.reverse ();
 
             foreach (unowned Json.Node node in artboards_list) {
-                load_item (node.get_object (), "artboard");
+                load_item (canvas, node.get_object (),  "artboard");
             }
         }
 
         // Load saved Items.
-        if (obj.get_member ("items") != null) {
-            Json.Array items = obj.get_member ("items").get_array ();
+        if (json_object.get_member ("items") != null) {
+            Json.Array items = json_object.get_member ("items").get_array ();
             var items_list = items.get_elements ();
             items_list.reverse ();
 
             foreach (unowned Json.Node node in items_list) {
-                load_item (node.get_object (), "item");
+                load_item (canvas, node.get_object (), "item");
             }
         }
 
-        window.event_bus.set_scale (obj.get_double_member ("scale"));
-        window.main_window.main_canvas.main_scroll.hadjustment.value = obj.get_double_member ("hadjustment");
-        window.main_window.main_canvas.main_scroll.vadjustment.value = obj.get_double_member ("vadjustment");
+        //window.event_bus.set_scale (obj.get_double_member ("scale"));
+        //window.main_window.main_canvas.main_scroll.hadjustment.value = obj.get_double_member ("hadjustment");
+        //window.main_window.main_canvas.main_scroll.vadjustment.value = obj.get_double_member ("vadjustment");
 
         // Reset the holding state at the end of it.
-        window.main_window.main_canvas.canvas.holding = false;
+        canvas.holding = false;
     }
 
-    private void load_item (Json.Object obj, string type) {
-        var item = obj.get_member (type).get_object ();
+    private static void load_item (Akira.Lib.Canvas canvas, Json.Object json_object, string type) {
+        var item = json_object.get_member (type).get_object ();
         if (item != null) {
             //  debug ("loading %s", type);
-            window.items_manager.load_item (item);
+            canvas.window.items_manager.load_item (item);
         }
     }
 }

src/Lib/Canvas.vala

@@ -53,6 +53,7 @@ public class Akira.Lib.Canvas : Goo.Canvas {
         MODE_PANNING,
     }
 
+    public Managers.UndoManager undo_manager;
     public Managers.ExportManager export_manager;
     public Managers.SelectedBoundManager selected_bound_manager;
     private Managers.NobManager nob_manager;
@@ -85,6 +86,7 @@ public class Akira.Lib.Canvas : Goo.Canvas {
         events |= Gdk.EventMask.TOUCHPAD_GESTURE_MASK;
         events |= Gdk.EventMask.TOUCH_MASK;
 
+        undo_manager = new Managers.UndoManager ();
         export_manager = new Managers.ExportManager (this);
         selected_bound_manager = new Managers.SelectedBoundManager (this);
         nob_manager = new Managers.NobManager (this);
@@ -258,6 +260,7 @@ public class Akira.Lib.Canvas : Goo.Canvas {
 
         switch (edit_mode) {
             case EditMode.MODE_INSERT:
+                undo_manager.add_undo(this);
                 selected_bound_manager.reset_selection ();
 
                 var new_item = window.items_manager.insert_item (event.x, event.y);
@@ -375,6 +378,7 @@ public class Akira.Lib.Canvas : Goo.Canvas {
                 break;
 
             case EditMode.MODE_SELECTION:
+                undo_manager.add_undo(this);
                 window.event_bus.detect_artboard_change ();
                 window.event_bus.detect_image_size_change ();
                 break;
@@ -424,6 +428,8 @@ public class Akira.Lib.Canvas : Goo.Canvas {
 
     public void on_insert_item () {
         edit_mode = EditMode.MODE_INSERT;
+
+        debug("add item");
     }
 
     public void on_set_focus_on_canvas () {

src/Lib/Managers/UndoManager.vala

@@ -0,0 +1,107 @@
+
+
+
+
+
+
+
+public class Akira.Lib.Managers.UndoManager : Object {
+
+    private GLib.Queue<string> undos;
+    private GLib.Queue<string> redos;
+
+    public UndoManager () {
+        undos = new GLib.Queue<string>();
+        redos = new GLib.Queue<string>();
+    }
+
+
+    public void add_undo(Akira.Lib.Canvas canvas) {
+        redos.clear ();
+        inner_add_undo(Akira.FileFormat.JsonContent.serialize_canvas(canvas));
+        debug("%d %d", (int)undos.get_length(), (int)redos.get_length());
+    }
+
+    public void apply_undo(Akira.Lib.Canvas canvas) {
+        if (undos.get_length () == 0)  {
+            debug("undo empty");
+            return;
+        }
+
+        var old_undo = undos.pop_head();
+        inner_add_redo(old_undo);
+
+        try {
+            var parser = new Json.Parser ();
+            parser.load_from_data (old_undo);
+            var obj = parser.get_root ().get_object ();
+
+            clear_canvas(canvas);
+            Akira.FileFormat.JsonLoader.inner_load_content(canvas, obj);
+
+        } catch (Error e) {
+            debug("failed to read undo");
+            return;
+        }
+
+        debug("%d %d", (int)undos.get_length(), (int)redos.get_length());
+    }
+
+    private void inner_add_undo(string undo_to_add) {
+      undos.push_head(undo_to_add);
+    }
+
+    private void inner_add_redo(string redo_to_add) {
+      redos.push_head(redo_to_add);
+    }
+
+    public void apply_redo(Akira.Lib.Canvas canvas) {
+        if (redos.get_length () == 0)  {
+            debug("redo empty");
+            return;
+        }
+
+        var old_redo = redos.pop_head();
+        inner_add_undo(old_redo);
+
+
+        try {
+            var parser = new Json.Parser ();
+            parser.load_from_data (old_redo);
+            var obj = parser.get_root ().get_object ();
+
+            clear_canvas(canvas);
+            Akira.FileFormat.JsonLoader.inner_load_content(canvas, obj);
+
+        } catch (Error e) {
+            debug("failed to read redo");
+            return;
+        }
+
+        debug("%d %d", (int)undos.get_length(), (int)redos.get_length());
+
+    }
+
+    private void clear_canvas(Akira.Lib.Canvas canvas) {
+        var item_manager = canvas.window.items_manager;
+
+        var to_delete = new GLib.Queue<Akira.Lib.Items.CanvasItem>();
+
+        foreach (var item in item_manager.free_items) {
+            to_delete.push_head(item);
+        }
+
+        foreach (var item in item_manager.artboards) {
+            to_delete.push_head(item);
+        }
+
+        foreach (var item in item_manager.images) {
+            to_delete.push_head(item);
+        }
+
+        while (to_delete.get_length () != 0) {
+            canvas.window.event_bus.request_delete_item (to_delete.pop_head());
+        }
+    }
+
+}

src/Services/ActionManager.vala

@@ -66,6 +66,8 @@ public class Akira.Services.ActionManager : Object {
     public const string ACTION_ESCAPE = "action_escape";
     public const string ACTION_SHORTCUTS = "action_shortcuts";
     public const string ACTION_PICK_COLOR = "action_pick_color";
+    public const string ACTION_UNDO = "action_undo";
+    public const string ACTION_REDO = "action_redo";
 
     public static Gee.MultiMap<string, string> action_accelerators = new Gee.HashMultiMap<string, string> ();
     public static Gee.MultiMap<string, string> typing_accelerators = new Gee.HashMultiMap<string, string> ();
@@ -104,6 +106,8 @@ public class Akira.Services.ActionManager : Object {
         { ACTION_ESCAPE, action_escape },
         { ACTION_SHORTCUTS, action_shortcuts },
         { ACTION_PICK_COLOR, action_pick_color },
+        { ACTION_UNDO, do_undo },
+        { ACTION_REDO, do_redo },
     };
 
     public ActionManager (Akira.Application akira_app, Akira.Window window) {
@@ -149,6 +153,9 @@ public class Akira.Services.ActionManager : Object {
         typing_accelerators.set (ACTION_DELETE, "Delete");
         typing_accelerators.set (ACTION_DELETE, "BackSpace");
         typing_accelerators.set (ACTION_TOGGLE_PIXEL_GRID, "<Shift>Tab");
+
+        typing_accelerators.set (ACTION_UNDO, "<Control>z");
+        typing_accelerators.set (ACTION_REDO, "<Control><Shift>z");
     }
 
     construct {
@@ -509,6 +516,16 @@ public class Akira.Services.ActionManager : Object {
         });
     }
 
+    private void do_undo () {
+        weak Akira.Lib.Canvas canvas = window.main_window.main_canvas.canvas;
+        canvas.undo_manager.apply_undo(canvas);
+    }
+
+    private void do_redo () {
+        weak Akira.Lib.Canvas canvas = window.main_window.main_canvas.canvas;
+        canvas.undo_manager.apply_redo(canvas);
+    }
+
     public static void action_from_group (string action_name, ActionGroup? action_group) {
         action_group.activate_action (action_name, null);
     }

src/meson.build

@@ -108,6 +108,7 @@ sources = files(
     'Lib/Managers/NobManager.vala',
     'Lib/Managers/SelectedBoundManager.vala',
     'Lib/Managers/SnapManager.vala',
+    'Lib/Managers/UndoManager.vala',
 
     'Lib/Selection/Nob.vala',